Code coverage tests

This page documents the degree to which the PARI/GP source code is tested by our public test suite, distributed with the source distribution in directory src/test/. This is measured by the gcov utility; we then process gcov output using the lcov frond-end.

We test a few variants depending on Configure flags on the pari.math.u-bordeaux.fr machine (x86_64 architecture), and agregate them in the final report:

The target is to exceed 90% coverage for all mathematical modules (given that branches depending on DEBUGLEVEL or DEBUGMEM are not covered). This script is run to produce the results below.

LCOV - code coverage report
Current view: top level - basemath - pclgp.c (source / functions) Coverage Total Hit
Test: PARI/GP v2.18.1 lcov report (development 31042-0fbe168e69) Lines: 77.2 % 2381 1838
Test Date: 2026-07-23 17:04:59 Functions: 85.0 % 180 153
Legend: Lines:     hit not hit

            Line data    Source code
       1              : /* Copyright (C) 2000, 2012  The PARI group.
       2              : 
       3              : This file is part of the PARI/GP package.
       4              : 
       5              : PARI/GP is free software; you can redistribute it and/or modify it under the
       6              : terms of the GNU General Public License as published by the Free Software
       7              : Foundation. It is distributed in the hope that it will be useful, but WITHOUT
       8              : ANY WARRANTY WHATSOEVER.
       9              : 
      10              : Check the License for details. You should have received a copy of it, along
      11              : with the package; see the file 'COPYING'. If not, write to the Free Software
      12              : Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */
      13              : 
      14              : #include "pari.h"
      15              : #include "paripriv.h"
      16              : 
      17              : #define DEBUGLEVEL DEBUGLEVEL_subcyclo
      18              : 
      19              : /* written by Takashi Fukuda */
      20              : 
      21              : #define onevec(x) const_vec(x,gen_1)
      22              : #define nullvec() cgetg(1, t_VEC)
      23              : #define order_f_x(f, x) Fl_order(x%f, eulerphiu(f), f)
      24              : 
      25              : #define USE_MLL         (1L<<0)
      26              : #define NO_PLUS_PART    (1L<<1)
      27              : #define NO_MINUS_PART   (1L<<2)
      28              : #define SKIP_PROPER     (1L<<3)
      29              : #define SAVE_MEMORY     (1L<<4)
      30              : #define USE_FULL_EL     (1L<<5)
      31              : #define USE_BASIS       (1L<<6)
      32              : #define USE_FACTOR      (1L<<7)
      33              : #define USE_GALOIS_POL  (1L<<8)
      34              : #define USE_F           (1L<<9)
      35              : 
      36              : static ulong
      37       178002 : _get_d(GEN H) { return umael(H, 2, 1);}
      38              : static ulong
      39       119820 : _get_f(GEN H) { return umael(H, 2, 2);}
      40              : static ulong
      41        30843 : _get_h(GEN H) { return umael(H, 2, 3);}
      42              : static long
      43        28392 : _get_s(GEN H) { return umael(H, 2, 4);}
      44              : static long
      45        53957 : _get_g(GEN H) { return umael(H, 2, 5);}
      46              : static GEN
      47        30787 : _get_H(GEN H) { return gel(H, 3);}
      48              : static ulong
      49       112755 : K_get_d(GEN K) { return _get_d(gel(K,1)); }
      50              : static ulong
      51        82965 : K_get_f(GEN K) { return _get_f(gel(K,1)); }
      52              : static ulong
      53        17424 : K_get_h(GEN K) { return _get_h(gel(K,1)); }
      54              : static long
      55            0 : K_get_s(GEN K) { return _get_s(gel(K,1)); }
      56              : static ulong
      57        17102 : K_get_g(GEN K) { return _get_g(gel(K,1)); }
      58              : static GEN
      59        17368 : K_get_H(GEN K) { return _get_H(gel(K,1)); }
      60              : static ulong
      61        59314 : K_get_dchi(GEN K) { return gel(K,6)[1]; }
      62              : static ulong
      63        23660 : K_get_nconj(GEN K) { return gel(K,6)[2]; }
      64              : 
      65              : /* G=<s> is a cyclic group of order n and t=s^(-1).
      66              :  *  convert sum_i a_i*s^i to sum_i b_i*t^i */
      67              : static GEN
      68           14 : Flx_recip1_inplace(GEN x, long pn)
      69              : {
      70           14 :   long i, lx = lg(x);
      71           14 :   if(lx-2 != pn) /* This case scarcely occurs */
      72              :   {
      73            0 :     long ly = pn+2;
      74            0 :     GEN y = const_vecsmall(ly, 0);
      75            0 :     y[1] = x[1];y[2] = x[2];
      76            0 :     for(i=3;i<lx;i++) y[ly+2-i] = x[i];
      77            0 :     return Flx_renormalize(y, ly);
      78              :   }
      79              :   else /* almost all cases */
      80              :   {
      81           14 :     long t, mid = (lx+1)>>1;
      82         7168 :     for(i=3;i<=mid;i++)
      83              :     {
      84         7154 :       t = x[i];x[i] = x[lx+2-i];x[lx+2-i] = t;
      85              :     }
      86           14 :     return Flx_renormalize(x, lx);
      87              :   }
      88              : }
      89              : 
      90              : /* Return h^degpol(P) P(x / h) */
      91              : static GEN
      92           14 : Flx_rescale_inplace(GEN P, ulong h, ulong p)
      93              : {
      94           14 :   long i, l = lg(P);
      95           14 :   ulong hi = h;
      96        14322 :   for (i=l-2; i>=2; i--)
      97              :   {
      98        14322 :     P[i] = Fl_mul(P[i], hi, p);
      99        14322 :     if (i == 2) break;
     100        14308 :     hi = Fl_mul(hi,h, p);
     101              :   }
     102           14 :   return P;
     103              : }
     104              : 
     105              : static GEN
     106           14 : zx_to_Flx_inplace(GEN x, ulong p)
     107              : {
     108           14 :   long i, lx = lg(x);
     109        14350 :   for (i=2; i<lx; i++) uel(x,i) = umodsu(x[i], p);
     110           14 :   return Flx_renormalize(x, lx);
     111              : }
     112              : 
     113              : /* zero pol of n components (i.e. deg=n-1). need to pass to ZX_renormalize */
     114              : INLINE GEN
     115        53263 : pol_zero(long n)
     116              : {
     117              :   long i;
     118        53263 :   GEN p = cgetg(n+2, t_POL);
     119        53263 :   p[1] = evalsigne(1) | evalvarn(0);
     120      1799812 :   for (i = 2; i < n+2; i++) gel(p, i) = gen_0;
     121        53263 :   return p;
     122              : }
     123              : 
     124              : /* e[i+1] = L*i + K for i >= n; determine K,L and reduce n if possible */
     125              : static GEN
     126           28 : vecsmall2vec2(GEN e, long n)
     127              : {
     128           28 :   long L = e[n+1] - e[n], K = e[n+1] - L*n;
     129           56 :   n--; while (n >= 0 && e[n+1] - L*n == K) n--;
     130           28 :   if (n < 0) e = nullvec(); else { setlg(e, n+2); e = zv_to_ZV(e); }
     131           28 :   return mkvec3(utoi(L), stoi(K), e); /* L >= 0 */
     132              : }
     133              : 
     134              : /* z=zeta_{p^n}; return k s.t. (z-1)^k || f(z) assuming deg(f)<phi(p^n) */
     135              : static long
     136           49 : zx_p_val(GEN f, ulong p, ulong n)
     137              : {
     138           49 :   pari_sp av = avma;
     139           49 :   ulong x = zx_lval(f, p);
     140           49 :   if (x) { f = zx_z_divexact(f, upowuu(p, x)); x *= (p-1)*upowuu(p, n-1); }
     141           49 :   x += Flx_val(Flx_translate1(zx_to_Flx(f, p), p));
     142           49 :   return gc_long(av, x);
     143              : }
     144              : 
     145              : static long
     146          315 : ZX_p_val(GEN f, ulong p, ulong n)
     147              : {
     148          315 :   pari_sp av = avma;
     149          315 :   ulong x = ZX_lval(f, p);
     150          315 :   if (x) { f = ZX_Z_divexact(f, powuu(p, x)); x *= (p-1)*upowuu(p, n-1); }
     151          315 :   x += Flx_val(Flx_translate1(ZX_to_Flx(f, p), p));
     152          315 :   return gc_long(av, x);
     153              : }
     154              : 
     155              : static GEN
     156           35 : set_A(GEN B, int *chi)
     157              : {
     158           35 :   long a, i, j, B1 = B[1], l = lg(B);
     159           35 :   GEN A = cgetg(l, t_VECSMALL);
     160      1687014 :   for (a = 0, j = 1; j < B1; j++) a += chi[j];
     161           35 :   A[1] = a;
     162          714 :   for (i = 2; i < l; i++)
     163              :   {
     164          679 :     long Bi = B[i];
     165     28159243 :     for (a = A[i-1], j = B[i-1]; j < Bi; j++) a += chi[j];
     166          679 :     A[i] = a;
     167              :   }
     168           35 :   return A;
     169              : }
     170              : 
     171              : /* g_n(a)=g_n(b) <==> a^2=b^2 mod 2^(n+2) <==> a=b,-b mod 2^(n+2)
     172              :  * g_n(a)=g_n(1+q0)^k <==> a=x(1+q0)^k x=1,-1
     173              :  * gam[1+a]=k, k<0  ==> g_n(a)=0
     174              :  *             k>=0 ==> g_n(a)^(-1)=gamma^k, gamma=g_n(1+q0) */
     175              : static GEN
     176           14 : set_gam2(long q01, long n)
     177              : {
     178              :   long i, x, x1, pn, pn2;
     179              :   GEN gam;
     180           14 :   pn = (1L<<n);
     181           14 :   pn2 = (pn<<2);
     182           14 :   gam = const_vecsmall(pn2, -1);
     183           14 :   x=Fl_inv(q01, pn2); x1=1;
     184        14350 :   for (i=0; i<pn; i++)
     185              :   {
     186        14336 :     gam[1+x1] = gam[1+Fl_neg(x1, pn2)] = i;
     187        14336 :     x1 = Fl_mul(x1, x, pn2);
     188              :   }
     189           14 :   return gam;
     190              : }
     191              : 
     192              : /* g_n(a)=g_n(b) <==> a^(p-1)=b^(p-1) mod p^(n+1) <==> a=xb x=<g^(p^n)>
     193              :  * g_n(a)=g_n(1+q0)^k <==> a=x(1+q0)^k x=<g^(p^n)>
     194              :  * gam[1+a]=k, k<0  ==> g_n(a)=0
     195              :  *             k>=0 ==> g_n(a)^(-1)=gamma^k, gamma=g_n(1+q0) */
     196              : static GEN
     197          476 : set_gam(long q01, long p, long n)
     198              : {
     199              :   long i, j, g, g1, x, x1, p1, pn, pn1;
     200              :   GEN A, gam;
     201          476 :   p1 = p-1; pn = upowuu(p, n); pn1 = p*pn;
     202          476 :   gam = const_vecsmall(pn1, -1);
     203          476 :   g = pgener_Zl(p); g1 = Fl_powu(g, pn, pn1);
     204          476 :   A = Fl_powers(g1, p1-1, pn1);  /* A[1+i]=g^(i*p^n) mod p^(n+1), 0<=i<=p-2 */
     205          476 :   x = Fl_inv(q01, pn1); x1 = 1;
     206       568694 :   for (i=0; i<pn; i++)
     207              :   {
     208      2086126 :     for (j=1; j<=p1; j++) gam[1+Fl_mul(x1, A[j], pn1)] = i;
     209       568218 :     x1 = Fl_mul(x1, x, pn1);
     210              :   }
     211          476 :   return gam;
     212              : }
     213              : 
     214              : /* k=Q(sqrt(m)), A_n=p-class gr. of k_n, |A_n|=p^(e_n)
     215              :  * return e_n-e_(n-1)
     216              :  * essential assumption : m is not divisible by p
     217              :  * Gold, Acta Arith. XXVI (1974), p.22 formula (3) */
     218              : static long
     219           35 : ediff(ulong p, long m, ulong n, int *chi)
     220              : {
     221           35 :   pari_sp av = avma;
     222              :   long j, lx, *px;
     223              :   ulong i, d, s, y, g, p1, pn, pn1, pn_1, phipn, phipn1;
     224              :   GEN A, B, x, gs, cs;
     225              : 
     226           35 :   d=((m-1)%4==0)?labs(m):4*labs(m);
     227           35 :   p1=p-1; pn_1=upowuu(p, n-1); pn=p*pn_1; pn1=p*pn; phipn=p1*pn_1; phipn1=p1*pn;
     228           35 :   lx=2*p1*phipn;
     229           35 :   y=Fl_inv(pn1%d, d); g=pgener_Zl(p);  /* pn1 may > d */
     230           35 :   cs = cgetg(2+phipn, t_VECSMALL); cs[1] = evalvarn(0);
     231           35 :   x = cgetg(1+lx, t_VECSMALL);
     232           35 :   gs = Fl_powers(g, phipn1-1, pn1); /* gs[1+i]=g^i(mod p^(n+1)), 0<=i<p^(n+1) */
     233              : 
     234          105 :   for (px=x,i=0; i<p1; i++)
     235              :   {
     236           70 :     long ipn=i*pn+1,ipnpn=ipn+phipn;
     237          546 :     for (s=0; s<phipn; s++)
     238              :     {
     239          476 :       *++px = (y*gs[s+ipn])%d;  /* gs[s+ipn] may > d */
     240          476 :       *++px = (y*gs[(s%pn_1)+ipnpn])%d;
     241              :     }
     242              :   }
     243           35 :   B = vecsmall_uniq(x);
     244           35 :   A = set_A(B, chi);
     245          273 :   for (s=0; s<phipn; s++)
     246              :   {
     247          238 :     long a=0, ipn=1, spn1=s%pn_1;
     248          714 :     for (i=0; i<p1; i++)
     249              :     {
     250          476 :       if ((j=zv_search(B, (y*gs[s+ipn])%d))<=0)
     251            0 :         pari_err_BUG("zv_search failed\n");
     252          476 :       a+=A[j];
     253          476 :       if ((j=zv_search(B, (y*gs[spn1+ipn+phipn])%d))<=0)
     254            0 :         pari_err_BUG("zv_search failed\n");
     255          476 :       a-=A[j];
     256          476 :       ipn+=pn;
     257              :     }
     258          238 :     cs[2+s] = a;
     259              :   }
     260           35 :   cs = zx_renormalize(cs, lg(cs));
     261           35 :   y = (lg(cs)==3) ? phipn*z_lval(cs[2], p) : zx_p_val(cs, p, n);
     262           35 :   return gc_long(av, y);
     263              : }
     264              : 
     265              : static GEN
     266            0 : quadteichstk(GEN Chi, int *chi, GEN Gam, long p, long m, long n)
     267              : {
     268            0 :   GEN Gam1 = Gam+1, xi;
     269              :   long i, j, j0, d, f0, pn, pn1, deg, pn1d;
     270              : 
     271            0 :   d = ((m&3)==1)?m:m<<2;
     272            0 :   f0 = ulcm(p, d)/p;
     273            0 :   pn = upowuu(p, n); pn1 = p*pn; pn1d = pn1%d;
     274            0 :   xi = cgetg(pn+2, t_POL); xi[1] = evalsigne(1) | evalvarn(0);
     275            0 :   for (i=0; i<pn; i++) gel(xi, 2+i) = const_vecsmall(p, 0);
     276            0 :   for (j=1; j<pn1; j++)
     277              :   {
     278              :     long jp, ipn1d, *xij0;
     279            0 :     if ((j0 = Gam1[j])<0) continue;
     280            0 :     jp = j%p; ipn1d = j%d; xij0 = gel(xi, 2+j0)+2;
     281            0 :     for (i=1; i<f0; i++)
     282              :     {
     283              :       int sgn;
     284            0 :       if ((ipn1d += pn1d) >= d) ipn1d -= d;
     285            0 :       if ((sgn = chi[ipn1d])==0) continue;
     286            0 :       deg = Chi[jp];  /* jp!=0 because j0>=0 */
     287            0 :       if (sgn>0) xij0[deg] += i;
     288            0 :       else xij0[deg] -= i;
     289              :     }
     290              :   }
     291            0 :   for (i=0; i<pn; i++) gel(xi, 2+i) = zx_renormalize(gel(xi, 2+i), p+1);
     292            0 :   return FlxX_renormalize(xi, pn+2);  /* zxX_renormalize does not exist */
     293              : }
     294              : 
     295              : #ifdef DEBUG_QUADSTK
     296              : /* return f0*xi_n */
     297              : static GEN
     298              : quadstkp_by_def(int *chi, GEN gam, long n, long p, long f, long f0)
     299              : {
     300              :   long i, a, a1, pn, pn1, qn;
     301              :   GEN x, x2, gam1 = gam+1;
     302              :   pn = upowuu(p, n); pn1 = p*pn; qn = f0*pn1;
     303              :   x = const_vecsmall(pn+1, 0); x2 = x+2;
     304              :   for (a=1; a<qn; a++)
     305              :   {
     306              :     int sgn;
     307              :     if ((a1=gam1[a%pn1])<0 || (sgn=chi[a%f])==0) continue;
     308              :     if (sgn>0) x2[a1]+=a;
     309              :     else x2[a1]-=a;
     310              :   }
     311              :   for (i=0; i<pn; i++)
     312              :   {
     313              :     if (x2[i]%pn1) pari_err_BUG("stickel. ele. is not integral.\n");
     314              :     else x2[i]/=pn1;
     315              :   }
     316              :   return zx_renormalize(x, pn+2);
     317              : }
     318              : #endif
     319              : 
     320              : /* f!=p
     321              :  * xi_n = f0^(-1)*
     322              :  *   sum_{0<=j<pn1,(j,p)=1}(Q_n/Q,j)^(-1)*(sum_{0<=i<f0}i*chi^(-1)(pn1*i+j)) */
     323              : static GEN
     324           14 : quadstkp1(int *chi, GEN gam, long n, long p, long f, long f0)
     325              : {
     326              :   long i, j, j0, pn, pn1, pn1f, den;
     327              :   GEN x, x2;
     328           14 :   pn = upowuu(p, n); pn1 = p*pn; pn1f = pn1%f;
     329           14 :   x = const_vecsmall(pn+1, 0); x2 = x+2;
     330           14 :   if (f==3) den = (chi[p%f]>0)?f0<<1:2;
     331           14 :   else if (f==4) den = (chi[p%f]>0)?f0<<1:f0;
     332           14 :   else den = f0<<1;
     333      1653372 :   for (j=1; j<pn1; j++)
     334              :   {
     335              :     long ipn1;
     336      1653358 :     if (j%p==0) continue;
     337      1102248 :     j0 = gam[1+j]; ipn1 = j%f;
     338    263437272 :     for (i=1; i<f0; i++)
     339              :     {
     340              :       int sgn;
     341    262335024 :       if ((ipn1+=pn1f)>=f) ipn1-=f;
     342    262335024 :       if ((sgn = chi[ipn1])>0) x2[j0]+=i;
     343    131716319 :       else if (sgn<0) x2[j0]-=i;
     344              :     }
     345              :   }
     346       551138 :   for (i=0; i<pn; i++)
     347              :   {
     348       551124 :     if (x2[i]%den) pari_err_BUG("stickel. ele. is not integral.\n");
     349       551124 :     else x2[i]/=den;
     350              :   }
     351           14 :   return zx_renormalize(x, pn+2);
     352              : }
     353              : 
     354              : /* f==p */
     355              : static GEN
     356            0 : quadstkp2(int *chi, GEN gam, long n, long p)
     357              : {
     358              :   long a, a1, i, pn, pn1, amodp;
     359            0 :   GEN x, x2, gam1 = gam+1;
     360            0 :   pn = upowuu(p, n); pn1 = p*pn;
     361            0 :   x = const_vecsmall(pn+1, 0); x2 = x+2;
     362            0 :   for (a=1,amodp=0; a<pn1; a++)
     363              :   {
     364              :     int sgn;
     365            0 :     if (++amodp==p) {amodp = 0; continue; }
     366            0 :     if ((sgn = chi[amodp])==0) continue;
     367            0 :     a1=gam1[a];
     368            0 :     if (sgn>0) x2[a1]+=a;
     369            0 :     else x2[a1]-=a;
     370              :   }
     371            0 :   for (i=0; i<pn; i++)
     372              :   {
     373            0 :     if (x2[i]%pn1) pari_err_BUG("stickel. ele. is not integral.\n");
     374            0 :     else x2[i]/=pn1;
     375              :   }
     376            0 :   return zx_renormalize(x, pn+2);
     377              : }
     378              : 
     379              : /*  p>=3
     380              :  *  f = conductor of Q(sqrt(m))
     381              :  *  q0 = lcm(f,p) = f0*p
     382              :  *  qn = q0*p^n = f0*p^(n+1)
     383              :  *  xi_n = qn^(-1)*sum_{1<=a<=qn,(a,qn)=1} a*chi(a)^(-1)*(Q_n/Q,a)^(-1) */
     384              : static GEN
     385           14 : quadstkp(long p, long m, long n, int *chi)
     386              : {
     387              :   long f, f0, pn, pn1, q0;
     388              :   GEN gam;
     389           14 :   f = ((m-1)%4==0)?labs(m):4*labs(m);
     390           14 :   pn = upowuu(p, n); pn1 = p*pn;
     391           14 :   if (f % p) { q0 = f * p; f0 = f; } else { q0 = f; f0 = f / p; }
     392           14 :   gam = set_gam((1+q0)%pn1, p, n);
     393              : #ifdef DEBUG_QUADSTK
     394              :   return quadstkp_by_def(chi, gam, n, p, f, f0);
     395              : #else
     396           14 :   return (f0!=1)?quadstkp1(chi, gam, n, p, f, f0):quadstkp2(chi, gam, n, p);
     397              : #endif
     398              : }
     399              : 
     400              : /* p=2 */
     401              : static GEN
     402           14 : quadstk2(long m, long n, int *chi)
     403              : {
     404              :   long i, j, j0, f, f0, pn, pn1, pn2, pn2f, q0;
     405              :   GEN x, x2, gam;
     406           14 :   f = ((m-1)%4==0)?labs(m):4*labs(m);
     407           14 :   pn = 1L<<n; pn1 = pn<<1; pn2 = pn1<<1; pn2f = pn2%f;
     408           14 :   q0 = (f&1)?f*4:f;
     409           14 :   f0 = (f&1)?f:f/4;
     410           14 :   x = const_vecsmall(pn+1, 0); x2 = x+2;
     411           14 :   gam = set_gam2((1+q0)%pn2, n);
     412        57344 :   for (j=1; j<pn2; j++)
     413              :   {
     414              :     long ipn2;
     415        57330 :     if (!(j&1)) continue;
     416        28672 :     j0 = gam[1+j];
     417        28672 :     ipn2 = j%f;
     418              :     /* for (i=1; i<f0; i++) x2[j0]+=i*chi[(i*pn2+j)%f]; */
     419      1691648 :     for (i=1; i<f0; i++)
     420              :     {
     421              :       int sgn;
     422      1662976 :       if ((ipn2+=pn2f)>=f) ipn2-=f;
     423      1662976 :       if ((sgn=chi[ipn2])>0) x2[j0]+=i;
     424       845390 :       else if (sgn<0) x2[j0]-=i;
     425              :     }
     426              :   }
     427        14350 :   for (f0<<=1, i=0; i<pn; i++)
     428              :   {
     429        14336 :     if (x2[i]%f0) pari_err_BUG("stickel. ele. is not integral.\n");
     430        14336 :     else x2[i]/=f0;
     431              :   }
     432           14 :   return zx_renormalize(x, pn+2);
     433              : }
     434              : 
     435              : /* Chin is a generator of the group of the characters of G(Q_n/Q).
     436              :  * chin[1+a]=k, k<0  ==> Chin(a)=0
     437              :  *              k>=0 ==> Chin(a)=zeta_{p^n}^k */
     438              : static GEN
     439           28 : set_chin(long p, long n)
     440              : {
     441           28 :   long i, j, x = 1, g, gpn, pn, pn1;
     442              :   GEN chin, chin1;
     443           28 :   pn = upowuu(p, n); pn1 = p*pn;
     444           28 :   chin = const_vecsmall(pn1, -1); chin1 = chin+1;
     445           28 :   g = pgener_Zl(p); gpn = Fl_powu(g, pn, pn1);
     446          322 :   for (i=0; i<pn; i++)
     447              :   {
     448          294 :     long y = x;
     449          882 :     for (j=1; j<p; j++)
     450              :     {
     451          588 :       chin1[y] = i;
     452          588 :       y = Fl_mul(y, gpn, pn1);
     453              :     }
     454          294 :     x = Fl_mul(x, g, pn1);
     455              :   }
     456           28 :   return chin;
     457              : }
     458              : 
     459              : /* k=Q(sqrt(m)), A_n=p-class gr. of k_n, |A_n|=p^(e_n), p|m
     460              :  * return e_n-e_(n-1).
     461              :  * There is an another method using the Stickelberger element based on
     462              :  * Coates-Lichtenbaum, Ann. Math. vol.98 No.3 (1973), 498-550, Lemma 2.15.
     463              :  * If kro(m,p)!=1, then orders of two groups coincide.
     464              :  * ediff_ber is faster than the Stickelberger element. */
     465              : static long
     466           28 : ediff_ber(ulong p, long m, ulong n, int *chi)
     467              : {
     468           28 :   pari_sp av = avma;
     469              :   long a, d, e, x, y, pn, pn1, qn1;
     470           28 :   GEN B, B2, chin = set_chin(p, n)+1;
     471              : 
     472           28 :   d = ((m-1)%4==0)?labs(m):4*labs(m);
     473           28 :   pn = upowuu(p, n); pn1 = p*pn; qn1 = (d*pn)>>1;
     474           28 :   B = const_vecsmall(pn+1, 0); B2 = B+2;
     475    522106886 :   for (a=x=y=1; a <= qn1; a++) /* x=a%d, y=a%pn1 */
     476              :   {
     477    522106858 :     int sgn = chi[x];
     478    522106858 :     if (sgn)
     479              :     {
     480    172938444 :       long k = chin[y];
     481    172938444 :       if (k >= 0) { if (sgn > 0) B2[k]++; else B2[k]--; }
     482              :     }
     483    522106858 :     if (++x == d) x = 0;
     484    522106858 :     if (++y == pn1) y = 0;
     485              :   }
     486           28 :   B = zx_renormalize(B, pn+2);
     487           14 :   e = (n==1)? zx_p_val(B, p, n)
     488           28 :             : ZX_p_val(ZX_rem(zx_to_ZX(B), polcyclo(pn, 0)), p, n);
     489           28 :   if (p==3 && chi[2] < 0) e--;  /* 2 is a primitive root of 3^n (n>=1) */
     490           28 :   return gc_long(av, e);
     491              : }
     492              : 
     493              : #ifdef DEBUG
     494              : static int*
     495              : set_quad_chi_slow(long m)
     496              : {
     497              :   long a, d = (m-1) % 4? 4*m: m, f = labs(d);
     498              :   int *chi = (int*)stack_calloc(sizeof(int)*f);
     499              :   for (a=1; a<f; a++) chi[a]=kross(d, a);
     500              :   return chi;
     501              : }
     502              : #endif
     503              : 
     504              : /* chi[a] = kross(d, a), 0 <= a < f, d = disc Q(sqrt(m)), f = abs(d)
     505              :  * Algorithm: m=-p1*p2*...*pr ==> kross(d,gi)=-1 (1<=i<=r), gi=proot(pi) */
     506              : static int*
     507           56 : set_quad_chi(long m)
     508              : {
     509           56 :   long d = (m-1) % 4? 4*m: m, f = labs(d);
     510           56 :   GEN fa = factoru(f), P = gel(fa, 1), E = gel(fa,2), u, v;
     511           56 :   long i, j, np, nm, l = lg(P);
     512           56 :   int *chi = (int*)stack_calloc(sizeof(int)*f);
     513           56 :   pari_sp av = avma;
     514           56 :   int *plus = (int*)stack_calloc(sizeof(int)*f), *p0 = plus;
     515           56 :   int *minus = (int*)stack_calloc(sizeof(int)*f), *p1 = minus;
     516              : 
     517           56 :   u = cgetg(32, t_VECSMALL);
     518           56 :   v = cgetg(32, t_VECSMALL);
     519          168 :   for (i = 1; i < l; i++)
     520              :   {
     521          112 :     ulong q = upowuu(P[i], E[i]), fq = f / q;
     522          112 :     u[i] = q * Fl_inv(q % fq, fq); /* 1 mod f/q, 0 mod q */
     523          112 :     v[i] = Fl_sub(1, u[i], f); /* => gv + u is 1 mod f/q and g mod q */
     524              :   }
     525           56 :   if (E[1]==2) /* f=4*(-m) */
     526              :   {
     527           14 :     *p0++ = Fl_add(v[1], u[1], f);
     528           14 :     *p1++ = Fl_add(Fl_mul(3, v[1], f), u[1], f);
     529           14 :     i = 2;
     530              :   }
     531           42 :   else if (E[1]==3) /* f=8*(-m) */
     532              :   {
     533              :     ulong a;
     534            7 :     *p0++ = Fl_add(v[1], u[1], f);
     535            7 :     a = Fl_add(Fl_mul(3, v[1], f), u[1], f);
     536            7 :     if (kross(d, a) > 0) *p0++ = a; else *p1++ = a;
     537            7 :     a = Fl_add(Fl_mul(5, v[1], f), u[1], f);
     538            7 :     if (kross(d, a) > 0) *p0++ = a; else *p1++ = a;
     539            7 :     a = Fl_add(Fl_mul(7, v[1], f), u[1], f);
     540            7 :     if (kross(d, a) > 0) *p0++ = a; else *p1++ = a;
     541            7 :     i = 2;
     542              :   }
     543              :   else /* f=-m */
     544           35 :   {*p0++ = 1; i = 1; }
     545          147 :   for (; i < l; i++)
     546              :   {
     547           91 :     ulong gn, g = pgener_Fl(P[i]);
     548           91 :     gn = g = Fl_add(Fl_mul(g, v[i], f), u[i], f);
     549           91 :     np = p0-plus;
     550           91 :     nm = p1-minus;
     551              :     for (;;)
     552              :     {
     553      4802616 :       for (j = 0; j < np; j++) *p1++ = Fl_mul(plus[j], gn, f);
     554      4799858 :       for (j = 0; j < nm; j++) *p0++ = Fl_mul(minus[j], gn, f);
     555         7784 :       gn = Fl_mul(gn, g, f); if (gn == 1) break;
     556      4763927 :       for (j= 0; j < np; j++) *p0++ = Fl_mul(plus[j], gn, f);
     557      4761204 :       for (j = 0; j < nm; j++) *p1++ = Fl_mul(minus[j], gn, f);
     558         7693 :       gn = Fl_mul(gn, g, f); if (gn == 1) break;
     559              :     }
     560              :   }
     561           56 :   np = p0-plus;
     562           56 :   nm = p1-minus;
     563      9548427 :   for (i = 0; i < np; i++) chi[plus[i]] = 1;
     564      9548427 :   for (i = 0; i < nm; i++) chi[minus[i]] = -1;
     565           56 :   set_avma(av); return chi;
     566              : }
     567              : 
     568              : static long
     569         8995 : srh_x(GEN T, long n, long x)
     570              : {
     571        30086 :   for (; x<n; x++) if (!T[x]) return x;
     572          623 :   return -1;
     573              : }
     574              : 
     575              : /* G is a cyclic group of order d. hat(G)=<chi>.
     576              :  * chi, chi^p, ... , chi^(p^(d_chi-1)) are conjugate.
     577              :  * {chi^j | j in C} are repre. of Q_p-congacy classes of inj. chars.
     578              :  *
     579              :  * C is a set of representatives of H/<p>, where H=(Z/dZ)^* */
     580              : static GEN
     581         1134 : set_C(long p, long d, long d_chi, long n_conj)
     582              : {
     583         1134 :   long i, j, x, y, pmodd = p%d;
     584         1134 :   GEN T = const_vecsmall(d, 0)+1;
     585         1134 :   GEN C = cgetg(1+n_conj, t_VECSMALL);
     586         1134 :   if (n_conj==1) { C[1] = 1; return C; }
     587         9618 :   for (i=0, x=1; x >= 0; x = srh_x(T, d, x))
     588              :   {
     589         8995 :     if (cgcd(x, d)==1) C[++i] = x;
     590        40929 :     for (j=0, y=x; j<d_chi; j++) T[y = Fl_mul(y, pmodd, d)] = 1;
     591              :   }
     592          623 :   return C;
     593              : }
     594              : 
     595              : static GEN
     596          343 : FpX_one_cyclo(long n, GEN p)
     597              : {
     598          343 :   if (lgefint(p)==3)
     599          301 :     return Flx_to_ZX(Flx_factcyclo(n, p[2], 1));
     600              :   else
     601           42 :     return FpX_factcyclo(n, p, 1);
     602              : }
     603              : 
     604              : static void
     605        17094 : Flx_red_inplace(GEN x, ulong p)
     606              : {
     607        17094 :   long i, l = lg(x);
     608       274540 :   for (i=2; i<l; i++) x[i] = uel(x, i)%p;
     609        17094 :   Flx_renormalize(x, l);
     610        17094 : }
     611              : 
     612              : /* x[i], T[i] < pn */
     613              : static GEN
     614        39046 : Flxq_xi_conj(GEN x, GEN T, long j, long d, long pn)
     615              : {
     616        39046 :   long i, deg = degpol(x);
     617        39046 :   GEN z = const_vecsmall(d+1, 0);
     618      1032304 :   for (i=0; i<=deg; i++) z[2+Fl_mul(i, j, d)] = x[2+i];
     619        39046 :   return Flx_rem(Flx_renormalize(z, d+2), T, pn);
     620              : }
     621              : 
     622              : static GEN
     623          966 : FlxqX_xi_conj(GEN x, GEN T, long j, long d, long pn)
     624              : {
     625          966 :   long i, l = lg(x);
     626              :   GEN z;
     627          966 :   z = cgetg(l, t_POL); z[1] = evalsigne(1) | evalvarn(0);
     628        40012 :   for (i=2; i<l; i++) gel(z, i) = Flxq_xi_conj(gel(x, i), T, j, d, pn);
     629          966 :   return z;
     630              : }
     631              : 
     632              : static GEN
     633            0 : FlxqX_xi_norm(GEN x, GEN T, long p, long d, long pn)
     634              : {
     635            0 :   long i, d_chi = degpol(T);
     636            0 :   GEN z = x, z1 = x;
     637            0 :   for (i=1; i<d_chi; i++)
     638              :   {
     639            0 :     z1 = FlxqX_xi_conj(z1, T, p, d, pn);
     640            0 :     z = FlxqX_mul(z, z1, T, pn);
     641              :   }
     642            0 :   return z;
     643              : }
     644              : 
     645              : /* assume 0 <= x[i], y[j] <= m-1 */
     646              : static GEN
     647           15 : FpV_shift_add(GEN x, GEN y, GEN m, long start, long end)
     648              : {
     649              :   long i, j;
     650       222300 :   for (i=start, j=1; i<=end; i++, j++)
     651              :   {
     652       222285 :     pari_sp av = avma;
     653       222285 :     GEN z = addii(gel(x, i), gel(y, j));
     654       222285 :     gel(x, i) = (cmpii(z, m) >= 0)? gc_INT(av, subii(z, m)): z;
     655              :   }
     656           15 :   return x;
     657              : }
     658              : 
     659              : /* assume 0 <= x[i], y[j] <= m-1 */
     660              : static GEN
     661           10 : FpV_shift_sub(GEN x, GEN y, GEN m, long start, long end)
     662              : {
     663              :   long i, j;
     664       112430 :   for (i=start, j=1; i<=end; i++, j++)
     665              :   {
     666       112420 :     pari_sp av = avma;
     667       112420 :     GEN z = subii(gel(x, i), gel(y, j));
     668       112420 :     gel(x, i) = (signe(z) < 0)? gc_INT(av, addii(z, m)): z;
     669              :   }
     670           10 :   return x;
     671              : }
     672              : 
     673              : /* assume 0 <= x[i], y[j] <= m-1 */
     674              : static GEN
     675          173 : Flv_shift_add(GEN x, GEN y, ulong m, long start, long end)
     676              : {
     677              :   long i, j;
     678      2320113 :   for (i=start, j=1; i<=end; i++, j++)
     679              :   {
     680      2319940 :     ulong xi = x[i], yj = y[j];
     681      2319940 :     x[i] = Fl_add(xi, yj, m);
     682              :   }
     683          173 :   return x;
     684              : }
     685              : 
     686              : /* assume 0 <= x[i], y[j] <= m-1 */
     687              : static GEN
     688          102 : Flv_shift_sub(GEN x, GEN y, ulong m, long start, long end)
     689              : {
     690              :   long i, j;
     691      1165182 :   for (i=start, j=1; i<=end; i++, j++)
     692              :   {
     693      1165080 :     ulong xi = x[i], yj = y[j];
     694      1165080 :     x[i] = Fl_sub(xi, yj, m);
     695              :   }
     696          102 :   return x;
     697              : }
     698              : 
     699              : /* return 0 if p|x. else return 1 */
     700              : INLINE long
     701          896 : Flx_divcheck(GEN x, ulong p)
     702              : {
     703          896 :   long i, l = lg(x);
     704          910 :   for (i=2; i<l; i++) if (uel(x, i)%p) return 1;
     705          448 :   return 0;
     706              : }
     707              : 
     708              : static long
     709          448 : FlxX_weier_deg(GEN pol, long p)
     710              : {
     711          448 :   long i, l = lg(pol);
     712          896 :   for (i=2; i<l && Flx_divcheck(gel(pol, i), p)==0; i++);
     713          448 :   return (i<l)?i-2:-1;
     714              : }
     715              : 
     716              : static long
     717         1582 : Flx_weier_deg(GEN pol, long p)
     718              : {
     719         1582 :   long i, l = lg(pol);
     720         3997 :   for (i=2; i<l && pol[i]%p==0; i++);
     721         1582 :   return (i<l)?i-2:-1;
     722              : }
     723              : 
     724              : static GEN
     725          308 : Flxn_shift_mul(GEN g, long n, GEN p, long d, long m)
     726              : {
     727          308 :   return Flx_shift(Flxn_mul(g, p, d, m), n);
     728              : }
     729              : 
     730              : INLINE long
     731         1057 : deg_trunc(long lam, long p, long n, long pn)
     732              : {
     733              :   long r, x, d;
     734         1260 :   for (r=1,x=p; x<lam; r++) x *= p;  /* r is min int s.t. lam<=p^r */
     735         1057 :   if ((d = (n-r+2)*lam+1)>=pn) d = pn;
     736         1057 :   return d;
     737              : }
     738              : 
     739              : /*  Flx_translate1_basecase(g, pn) becomes slow when degpol(g)>1000.
     740              :  *  So I wrote Flxn_translate1().
     741              :  *  I need lambda to truncate pol.
     742              :  *  But I need to translate T --> 1+T to know lambda.
     743              :  *  Though the code has a little overhead, it is still fast. */
     744              : static GEN
     745          756 : Flxn_translate1(GEN g, long p, long n)
     746              : {
     747              :   long i, j, d, lam, pn, start;
     748          756 :   if (n==1) start = 3;
     749           70 :   else if (n==2) start = 9;
     750           70 :   else start = 10;
     751          756 :   pn = upowuu(p, n);
     752          756 :   for (lam=start; lam; lam<<=1)  /* least upper bound is 3 */
     753              :   {
     754              :     GEN z;
     755          756 :     d = deg_trunc(lam, p, n, pn);
     756          756 :     z = const_vecsmall(d+1, 0);  /* z[2],...,z[d+1] <--> a_0,...,a_{d-1} */
     757        44954 :     for (i=degpol(g); i>=0; i--)
     758              :     {
     759      1683486 :       for (j=d+1; j>2; j--) z[j] = Fl_add(z[j], z[j-1], pn);  /* z = z*(1+T) */
     760        44198 :       z[2] = Fl_add(z[2], g[2+i], pn);
     761              :     }
     762          756 :     z = Flx_renormalize(z, d+2);
     763          756 :     if (Flx_weier_deg(z, p) <= lam) return z;
     764              :   }
     765              :   return NULL; /*LCOV_EXCL_LINE*/
     766              : }
     767              : 
     768              : static GEN
     769          224 : FlxXn_translate1(GEN g, long p, long n)
     770              : {
     771              :   long i, j, d, lam, pn, start;
     772              :   GEN z;
     773          224 :   if (n==1) start = 3;
     774            0 :   else if (n==2) start = 9;
     775            0 :   else start = 10;
     776          224 :   pn = upowuu(p, n);
     777          224 :   for (lam=start; lam; lam<<=1)  /* least upper bound is 3 */
     778              :   {
     779          224 :     d = deg_trunc(lam, p, n, pn);
     780          224 :     z = const_vec(d+1, pol0_Flx(0));  /* z[2],...,z[d+1] <--> a_0,...,a_{d-1} */
     781          224 :     settyp(z, t_POL); z[1] = evalsigne(1) | evalvarn(0);
     782         9408 :     for (i=degpol(g); i>=0; i--)
     783              :     {
     784        64288 :       for (j=d+1; j>2; j--) gel(z, j) = Flx_add(gel(z, j), gel(z, j-1), pn);
     785         9184 :       gel(z, 2) = Flx_add(gel(z, 2), gel(g, 2+i), pn);
     786              :     }
     787          224 :     z = FlxX_renormalize(z, d+2);
     788          224 :     if (FlxX_weier_deg(z, p) <= lam) return z;
     789              :   }
     790              :   return NULL; /*LCOV_EXCL_LINE*/
     791              : }
     792              : 
     793              : /* lam < 0 => error (lambda can't be determined)
     794              :  * lam = 0 => return 1
     795              :  * lam > 0 => return dist. poly. of degree lam. */
     796              : static GEN
     797           84 : Flxn_Weierstrass_prep(GEN g, long p, long n, long d_chi)
     798              : {
     799           84 :   long i, r0, d, dg = degpol(g), lam, pn, t;
     800              :   ulong lam0;
     801              :   GEN U, UINV, P, PU, g0, g1, gp, gU;
     802           84 :   if ((lam = Flx_weier_deg(g, p))==0) return(pol1_Flx(0));
     803           77 :   else if (lam<0)
     804            0 :     pari_err(e_MISC,"Flxn_Weierstrass_prep: precision too low. Increase n!");
     805           77 :   lam0 = lam/d_chi;
     806           77 :   pn = upowuu(p, n);
     807           77 :   d = deg_trunc(lam, p, n, pn);
     808           77 :   if (d>dg) d = dg;
     809           77 :   if (d<=lam) d=1+lam;
     810          140 :   for (r0=1; upowuu(p, r0)<lam0; r0++);
     811           77 :   g = Flxn_red(g, d);
     812           77 :   t = Fl_inv(g[2+lam], pn);
     813           77 :   g = Flx_Fl_mul(g, t, pn);  /* normalized so as g[2+lam]=1 */
     814           77 :   U = Flx_shift(g, -lam);
     815           77 :   UINV = Flxn_inv(U, d, pn);
     816           77 :   P = zx_z_divexact(Flxn_red(g, lam), p);  /* assume g[i] <= LONG_MAX */
     817           77 :   PU = Flxn_mul(P, UINV, d, pn);
     818           77 :   gU = Flxn_mul(g, UINV, d, pn);
     819           77 :   g0 = pol1_Flx(0);
     820           77 :   g1 = pol1_Flx(0);
     821          385 :   for (i=1; i<n; i++)
     822              :   {
     823          308 :     g1 = Flxn_shift_mul(g1, -lam, PU, d, pn);
     824          308 :     gp = Flx_Fl_mul(g1, upowuu(p, i), pn);
     825          308 :     g0 = (i&1)?Flx_sub(g0, gp, pn):Flx_add(g0, gp, pn);
     826              :   }
     827           77 :   g0 = Flxn_mul(g0, gU, lam+1, pn);
     828           77 :   g0 = Flx_red(g0, upowuu(p, (p==2)?n-r0:n+1-r0));
     829           77 :   return g0;
     830              : }
     831              : 
     832              : /* xi_n and Iwasawa pol. for Q(sqrt(m)) and p
     833              :  *
     834              :  * (flag&1)!=0 ==> output xi_n
     835              :  * (flag&2)!=0 ==> output power series
     836              :  * (flag&4)!=0 ==> output Iwasawa polynomial */
     837              : static GEN
     838           14 : imagquadstkpol(long p, long m, long n)
     839              : {
     840           14 :   long pn = upowuu(p, n);
     841              :   GEN pol, stk, stk2;
     842              :   int *chi;
     843           14 :   if (p==2 && (m==-1 || m==-2 || m==-3 || m==-6)) return nullvec();
     844           14 :   if (p==3 && m==-3) return nullvec();
     845           14 :   if (p==2 && m%2==0) m /= 2;
     846           14 :   chi = set_quad_chi(m);
     847           14 :   stk = (p==2)? quadstk2(m, n, chi): quadstkp(p, m, n, chi);
     848           14 :   stk2 = zx_to_Flx(stk, pn);
     849           14 :   pol = Flxn_Weierstrass_prep(zlx_translate1(stk2, p, n), p, n, 1);
     850           14 :   return degpol(pol)? mkvec(Flx_to_ZX(pol)): nullvec();
     851              : }
     852              : 
     853              : /* a mod p == g^i mod p ==> omega(a)=zeta_(p-1)^(-i)
     854              :  *  Chi[g^i mod p]=i (0 <= i <= p-2) */
     855              : static GEN
     856            0 : get_teich(long p, long g)
     857              : {
     858            0 :   long i, gi = 1, p1 = p-1;
     859            0 :   GEN Chi = cgetg(p, t_VECSMALL);
     860            0 :   for (i=0; i<p1; i++) { Chi[gi] = i; gi = Fl_mul(gi, g, p); }
     861            0 :   return Chi;
     862              : }
     863              : 
     864              : /* Ichimura-Sumida criterion for Greenberg conjecture for real quadratic field.
     865              :  * chi: character of Q(sqrt(m)), omega: Teichmuller character mod p or 4.
     866              :  * Get Stickelberger element from chi^* = omega*chi^(-1) and convert it to
     867              :  * power series by the correspondence (Q_n/Q,1+q0)^(-1) <-> (1+T)(1+q0)^(-1) */
     868              : static GEN
     869           14 : realquadstkpol(long p, long m, long n)
     870              : {
     871              :   int *chi;
     872           14 :   long pnm1 = upowuu(p, n-1),pn = p*pnm1, pn1 = p*pn, d, q0;
     873              :   GEN stk, ser, pol;
     874           14 :   if (m==1) pari_err_DOMAIN("quadstkpol", "m", "=", gen_1, gen_1);
     875           14 :   if (p==2 && (m&1)==0) m>>=1;
     876           14 :   d = ((m&3)==1)?m:m<<2;
     877           14 :   q0 = ulcm((p==2)?4:p, d);
     878           14 :   if (p==2)
     879              :   {
     880           14 :     chi = set_quad_chi(-m);
     881           14 :     stk = quadstk2(-m, n, chi);
     882           14 :     stk = zx_to_Flx_inplace(stk, pn);
     883              :   }
     884            0 :   else if (p==3 && m%3==0 && kross(-m/3,3)==1)
     885            0 :   {
     886            0 :     long m3 = m/3;
     887            0 :     chi = set_quad_chi(-m3);
     888            0 :     stk = quadstkp(3, -m3, n, chi);
     889            0 :     stk = zx_to_Flx_inplace(stk, pn);
     890              :   }
     891              :   else
     892              :   {
     893            0 :     long g = pgener_Zl(p);
     894            0 :     long x = Fl_powu(Fl_inv(g, p), pnm1, pn);
     895            0 :     GEN Chi = get_teich(p, g);
     896            0 :     GEN Gam = set_gam((1+q0)%pn1, p, n);
     897            0 :     chi = set_quad_chi(m);
     898            0 :     stk = quadteichstk(Chi, chi, Gam, p, m, n);  /* exact */
     899            0 :     stk = zxX_to_FlxX(stk, pn);  /* approx. */
     900            0 :     stk = FlxY_evalx(stk, x, pn);
     901              :   }
     902           14 :   stk = Flx_rescale_inplace(Flx_recip1_inplace(stk, pn), (1+q0)%pn, pn);
     903           14 :   ser = Flxn_translate1(stk, p, n);
     904           14 :   pol = Flxn_Weierstrass_prep(ser, p, n, 1);
     905           14 :   return degpol(pol)? mkvec(Flx_to_ZX(pol)): nullvec();
     906              : }
     907              : 
     908              : /* m > 0 square-free. lambda_2(Q(sqrt(-m)))
     909              :  * Kida, Tohoku Math. J. vol.31 (1979), 91-96, Theorem 1. */
     910              : static GEN
     911            0 : quadlambda2(long m)
     912              : {
     913              :   long i, l, L;
     914              :   GEN P;
     915            0 :   if ((m&1)==0) m >>= 1;  /* lam_2(Q(sqrt(-m)))=lam_2(Q(sqrt(-2*m))) */
     916            0 :   if (m <= 3) return mkvecs(0);
     917            0 :   P = gel(factoru(m), 1); l = lg(P);
     918            0 :   for (L = -1,i = 1; i < l; i++) L += 1L << (-3 + vals(P[i]-1) + vals(P[i]+1));
     919            0 :   return mkvecs(L);
     920              : }
     921              : 
     922              : /* Iwasawa lambda invariant of Q(sqrt(m)) (m<0) for p
     923              :  * |A_n|=p^(e[n])
     924              :  * kross(m,p)!=1 : e[n]-e[n-1]<eulerphi(p^n)  ==> lambda=e[n]-e[n-1]
     925              :  * kross(m,p)==1 : e[n]-e[n-1]<=eulerphi(p^n) ==> lambda=e[n]-e[n-1]
     926              :  * Gold, Acta Arith. XXVI (1974), p.25, Cor. 3
     927              :  * Gold, Acta Arith. XXVI (1975), p.237, Cor. */
     928              : static GEN
     929           28 : quadlambda(long p, long m)
     930              : {
     931              :   long flag, n, phipn;
     932           28 :   GEN e = cgetg(31, t_VECSMALL);
     933              :   int *chi;
     934           28 :   if (m>0) pari_err_IMPL("plus part of lambda invariant in quadlambda()");
     935           28 :   if (p==2) return quadlambda2(-m);
     936           28 :   if (p==3 && m==-3) return mkvec3(gen_0, gen_0, nullvec());
     937           28 :   flag = kross(m, p);
     938           28 :   e[1] = Z_lval(quadclassno(quaddisc(stoi(m))), p);
     939           28 :   if (flag!=1 && e[1]==0) return mkvec3(gen_0, gen_0, nullvec());
     940           28 :   chi = set_quad_chi(m);
     941           28 :   phipn = p-1;  /* phipn=phi(p^n) */
     942           63 :   for (n=1; n; n++, phipn *= p)
     943              :   {
     944           63 :     long L = flag? ediff(p, m, n, chi): ediff_ber(p, m, n, chi);
     945           63 :     e[n+1] = e[n] + L;
     946           63 :     if ((flag!=1 && (L < phipn))|| (flag==1 && (L <= phipn))) break;
     947              :   }
     948           28 :   return vecsmall2vec2(e, n);
     949              : }
     950              : 
     951              : /* factor n-th cyclotomic polynomial mod p^r and return a minimal
     952              :  *  polynomial of zeta_n over Q_p.
     953              :  *  phi(n)=deg*n_conj, n_conj == 1 <=> polcyclo(n) is irred mod p. */
     954              : static GEN
     955          945 : set_minpol(ulong n, GEN p, ulong r, long n_conj)
     956              : {
     957              :   GEN z, v, pol, pr;
     958              :   pari_timer ti;
     959          945 :   if (umodiu(p, n)==1) /* zeta_n in Z_p, faster than polcyclo() */
     960              :   {
     961          420 :     GEN prm1 = powiu(p, r-1), pr = mulii(prm1, p); /* pr=p^r */
     962          420 :     GEN prn = diviuexact(subii(pr, prm1), n);      /* prn=phi(p^r)/n */
     963          420 :     z = Fp_pow(pgener_Fp(p), prn, pr);
     964          420 :     return deg1pol_shallow(gen_1, Fp_neg(z, pr), 0);
     965              :   }
     966          525 :   pr = powiu(p, r);
     967          525 :   pol = polcyclo(n, 0);
     968          525 :   if (n_conj==1) return FpX_red(pol, pr);
     969          343 :   if (DEBUGLEVEL>3) timer_start(&ti);
     970          343 :   z = FpX_one_cyclo(n, p);
     971          343 :   if (DEBUGLEVEL>3) timer_printf(&ti, "FpX_one_cyclo:n=%ld  ", n);
     972          343 :   v = ZpX_liftfact(pol, mkvec2(z, FpX_div(pol, z, p)), pr, p, r);
     973          343 :   return gel(v, 1);
     974              : }
     975              : 
     976              : static GEN
     977           91 : set_minpol_teich(ulong g_K, GEN p, ulong r)
     978              : {
     979           91 :   GEN prm1 = powiu(p, r-1), pr = mulii(prm1, p), z;
     980           91 :   z = Fp_pow(Fp_inv(utoi(g_K), p), prm1, pr);
     981           91 :   return deg1pol_shallow(gen_1, Fp_neg(z, pr), 0);
     982              : }
     983              : 
     984              : static long
     985        18963 : srh_1(GEN H)
     986              : {
     987        18963 :   GEN bits = gel(H, 3);
     988        18963 :   ulong f = bits[1];
     989        18963 :   return F2v_coeff(bits, f-1);
     990              : }
     991              : 
     992              : /* (1/f)sum_{1<=a<=f}a*chi^{-1}(a) = -(1/(2-chi(a)))sum_{1<=a<=f/2} chi^{-1}(a)
     993              :  *  does not overflow */
     994              : static GEN
     995        13146 : zx_ber_num(GEN Chi, long f, long d)
     996              : {
     997        13146 :   long i, f2 = f>>1;
     998        13146 :   GEN x = const_vecsmall(d+1, 0), x2 = x+2;
     999     51965081 :   for (i = 1; i <= f2; i++)
    1000     51951935 :     if (Chi[i] >= 0) x2[Chi[i]] ++;
    1001        13146 :   return zx_renormalize(x, d+2);
    1002              : }
    1003              : 
    1004              : /* x a zx
    1005              :  * zx_ber_num is O(f). ZX[FpX,Flx]_ber_conj is O(d). Sometimes d<<f. */
    1006              : static GEN
    1007        26257 : ZX_ber_conj(GEN x, long j, long d)
    1008              : {
    1009        26257 :   long i, deg = degpol(x);
    1010        26257 :   GEN y = pol_zero(d), x2 = x+2, y2 = y+2;
    1011       818202 :   for (i=0; i<=deg; i++) gel(y2, Fl_mul(i, j, d)) = stoi(x2[i]);
    1012        26257 :   return ZX_renormalize(y, d+2);
    1013              : }
    1014              : 
    1015              : /* x a zx */
    1016              : static GEN
    1017          252 : FpX_ber_conj(GEN x, long j, long d, GEN p)
    1018              : {
    1019          252 :   long i, deg = degpol(x);
    1020          252 :   GEN y = pol_zero(d), x2 = x+2, y2 = y+2;
    1021          756 :   for (i=0; i<=deg; i++) gel(y2, Fl_mul(i, j, d)) = modsi(x2[i], p);
    1022          252 :   return FpX_renormalize(y, d+2);
    1023              : }
    1024              : 
    1025              : /* x a zx */
    1026              : static GEN
    1027        21756 : Flx_ber_conj(GEN x, long j, long d, ulong p)
    1028              : {
    1029        21756 :   long i, deg = degpol(x);
    1030        21756 :   GEN y = const_vecsmall(d+1, 0), x2 = x+2, y2 = y+2;
    1031      1076565 :   for (i=0; i<=deg; i++) y2[Fl_mul(i, j, d)] = umodsu(x2[i], p);
    1032        21756 :   return Flx_renormalize(y, d+2);
    1033              : }
    1034              : 
    1035              : static GEN
    1036        26257 : ZX_ber_den(GEN Chi, long j, long d)
    1037              : {
    1038        26257 :   GEN x = pol_zero(d), x2 = x+2;
    1039        26257 :   if (Chi[2]>=0) gel(x2, Fl_neg(Fl_mul(Chi[2], j, d), d)) = gen_1;
    1040        26257 :   gel(x2, 0) = subiu(gel(x2, 0), 2);
    1041        26257 :   return ZX_renormalize(x, d+2);
    1042              : }
    1043              : 
    1044              : static GEN
    1045        14490 : Flx_ber_den(GEN Chi, long j, long d, ulong p)
    1046              : {
    1047        14490 :   GEN x = const_vecsmall(d+1, 0), x2 = x+2;
    1048        14490 :   if (Chi[2]>=0) x2[Fl_neg(Fl_mul(Chi[2], j, d), d)] = 1;
    1049        14490 :   x2[0] = Fl_sub(x2[0], 2, p);
    1050        14490 :   return Flx_renormalize(x, d+2);
    1051              : }
    1052              : 
    1053              : /* x is ZX of deg <= d-1 */
    1054              : static GEN
    1055          196 : ber_conj(GEN x, long k, long d)
    1056              : {
    1057          196 :   long i, deg = degpol(x);
    1058          196 :   GEN z = pol_zero(d);
    1059          196 :   if (k==1)
    1060            0 :     for (i=0; i<=deg; i++) gel(z, 2+i) = gel(x, 2+i);
    1061              :   else
    1062       122206 :     for (i=0; i<=deg; i++) gel(z, 2+Fl_mul(i, k, d)) = gel(x, 2+i);
    1063          196 :   return ZX_renormalize(z, d+2);
    1064              : }
    1065              : 
    1066              : /* The computation is fast when p^n and el=1+k*f*p^n are less than 2^64
    1067              :  *  for m <= n <= M
    1068              :  *  We believe M>=3 is enough when f%p=0 and M>=2 is enough for other case
    1069              :  *  because we expect that p^2 does not divide |A_{K,psi}| for a large p.
    1070              :  *  FIXME: M should be set according to p and f. */
    1071              : static void
    1072          196 : set_p_f(GEN pp, ulong f, long *pm, long *pM)
    1073              : {
    1074          196 :   ulong p = itou_or_0(pp);
    1075          196 :   if (!p || p >= 2000000) { *pm=2; *pM = dvdui(f, pp)? 3: 2; }
    1076          189 :   else if (p == 3)      { *pm=5; *pM=20; }
    1077          119 :   else if (p == 5)      { *pm=5; *pM=13; }
    1078           56 :   else if (p == 7)      { *pm=5; *pM=11; }
    1079           42 :   else if (p == 11)     { *pm=5; *pM=9; }
    1080           35 :   else if (p == 13)     { *pm=5; *pM=8; }
    1081           28 :   else if (p < 400)     { *pm=5; *pM=7; }
    1082            0 :   else if (p < 5000)    { *pm=3; *pM=5; }
    1083            0 :   else if (p < 50000)   { *pm=2; *pM=4; }
    1084            0 :   else                  { *pm=2; *pM=3; }
    1085          196 : }
    1086              : 
    1087              : static GEN
    1088        18795 : subgp2ary(GEN H, long n)
    1089              : {
    1090        18795 :   GEN v = gel(H, 3), w = cgetg(n+1, t_VECSMALL);
    1091        18795 :   long i, j, f = v[1];
    1092    399982464 :   for (i = 1, j = 0; i <= f; i++)
    1093    399963669 :     if (F2v_coeff(v,i)) w[++j] = i;
    1094        18795 :   return w;
    1095              : }
    1096              : 
    1097              : static GEN
    1098        19124 : Flv_FlvV_factorback(GEN g, GEN x, ulong q)
    1099        90216 : { pari_APPLY_ulong(Flv_factorback(g, gel(x,i), q)) }
    1100              : 
    1101              : /* lift chi character on G/H to character on G */
    1102              : static GEN
    1103        18795 : zncharlift(GEN chi, GEN ncycGH, GEN U, GEN cycG)
    1104              : {
    1105        18795 :   GEN nchi = char_normalize(chi, ncycGH);
    1106        18795 :   GEN c = ZV_ZM_mul(gel(nchi, 2), U), d = gel(nchi, 1);
    1107        18795 :   return char_denormalize(cycG, d, c);
    1108              : }
    1109              : 
    1110              : /* 0 <= c[i] < d, i=1..r; (c[1],...,c[r], d) = 1; find e[i] such that
    1111              :  * sum e[i]*c[i] = 1 mod d */
    1112              : static GEN
    1113        18795 : Flv_extgcd(GEN c, ulong d)
    1114              : {
    1115        18795 :   long i, j, u, f, l = lg(c);
    1116        18795 :   GEN e = zero_zv(l-1);
    1117        18795 :   if (l == 1) return e;
    1118        46053 :   for (f = d, i = 1; f != 1 && i < l; i++)
    1119              :   {
    1120        27258 :     f = cbezout(f, itou(gel(c,i)), &u, &e[i]);
    1121        27258 :     if (!e[i]) continue;
    1122        25004 :     e[i] = umodsu(e[i], d);
    1123        25004 :     u = umodsu(u, d);
    1124        32998 :     if (u != 1) for (j = 1; j < i; j++) e[j] = Fl_mul(e[j], u, d);
    1125              :   }
    1126        18795 :   return e;
    1127              : }
    1128              : 
    1129              : /* f!=p; return exact xi. */
    1130              : static GEN
    1131          462 : get_xi_1(GEN Chi, GEN Gam, long p, long f, long n, long d, ulong pm)
    1132              : {
    1133          462 :   GEN Gam1 = Gam+1, xi;
    1134              :   long i, j, j0, f0, pn, pn1, deg, pn1f;
    1135              : 
    1136          462 :   f0 = (f%p)?f:f/p;
    1137          462 :   pn = upowuu(p, n); pn1 = p*pn; pn1f = pn1%f;
    1138          462 :   xi = cgetg(pn+2, t_POL); xi[1] = evalsigne(1) | evalvarn(0);
    1139        17556 :   for (i=0; i<pn; i++) gel(xi, 2+i) = const_vecsmall(d+1, 0);
    1140       432754 :   for (j=1; j<pn1; j++)
    1141              :   {
    1142              :     long ipn1,*xij0;
    1143       432292 :     if ((j0 = Gam1[j])<0) continue;
    1144       415660 :     ipn1 = j%f; xij0 = gel(xi, 2+j0)+2;
    1145   4027401588 :     for (i=1; i<f0; i++)
    1146              :     {
    1147   4026985928 :       if ((ipn1 += pn1f) >= f) ipn1 -= f;
    1148   4026985928 :       if (ipn1==0 || (deg = Chi[ipn1])<0) continue;
    1149   2203029612 :       xij0[deg] += i;
    1150              :     }
    1151              :   }
    1152        17556 :   for (i=0; i<pn; i++) Flx_red_inplace(gel(xi, 2+i), pm);
    1153          462 :   return FlxX_renormalize(xi, pn+2);
    1154              : }
    1155              : 
    1156              : /* f=p; return p^(n+1)*xi mod pm. */
    1157              : static GEN
    1158            0 : get_xi_2(GEN Chi, GEN Gam, long p, long f, long n, long d, ulong pm)
    1159              : {
    1160              :   long a, amodf, i, j0, pn, pn1, deg;
    1161            0 :   GEN Gam1 = Gam+1, xi;
    1162              : 
    1163            0 :   pn = upowuu(p, n); pn1 = p*pn;
    1164            0 :   xi = cgetg(pn+2, t_POL); xi[1] = evalsigne(1) | evalvarn(0);
    1165            0 :   for (i=0; i<pn; i++) gel(xi, 2+i) = const_vecsmall(d+1, 0);
    1166            0 :   for (a=1,amodf=0; a<pn1; a++)  /* xi is exact */
    1167              :   {
    1168            0 :     if (++amodf==f) amodf = 0;
    1169            0 :     if ((j0=Gam1[a])<0 || amodf==0 || (deg=Chi[amodf])<0) continue;
    1170            0 :     mael(xi, 2+j0, 2+deg) += a;
    1171              :   }
    1172            0 :   for (i=0; i<pn; i++) Flx_red_inplace(gel(xi, 2+i), pm);
    1173            0 :   return FlxX_renormalize(xi, pn+2);
    1174              : }
    1175              : 
    1176              : static GEN
    1177           56 : pol_chi_xi(GEN K, long p, long j, long n)
    1178              : {
    1179           56 :   pari_sp av = avma;
    1180           56 :   GEN MinPol2 = gel(K, 7), xi = gel(K, 8);
    1181           56 :   long d = K_get_d(K), f = K_get_f(K), d_chi = K_get_dchi(K);
    1182           56 :   long wd, minpolpow = (f==p)?2*n+1:n, pm = upowuu(p, minpolpow);
    1183              :   GEN ser, pol, xi_conj;
    1184              :   pari_timer ti;
    1185              : 
    1186              :   /* xi is FlxX mod p^m, MinPol2 is Flx mod p^m, xi_conj is FlxqX. */
    1187           56 :   xi_conj = FlxqX_xi_conj(xi, MinPol2, j, d, pm);
    1188           56 :   if (d_chi==1)  /* d_chi==1 if f==p */
    1189              :   {
    1190           56 :     xi_conj = FlxX_to_Flx(xi_conj);
    1191           56 :     if (f==p) xi_conj = zx_z_divexact(xi_conj, upowuu(p, n+1));
    1192              :   }
    1193              :   /* Now xi_conj is mod p^n */
    1194           56 :   if (DEBUGLEVEL>1) timer_start(&ti);
    1195           56 :   ser = (d_chi==1) ? Flxn_translate1(xi_conj, p, n)
    1196           56 :     : FlxXn_translate1(xi_conj, p, n);
    1197           56 :   if (DEBUGLEVEL>1) timer_printf(&ti, "Flx%sn_translate1",(d_chi==1)?"":"X");
    1198           56 :   wd = (d_chi==1)?Flx_weier_deg(ser, p):FlxX_weier_deg(ser, p);
    1199           56 :   if (wd<0) pari_err(e_MISC,"pol_chi_xi: precision too low. Increase n!\n");
    1200           56 :   else if (wd==0) return pol_1(0);
    1201              :   /* wd>0, convert to dist. poly. */
    1202           56 :   if (d_chi>1)  /* f!=p. minpolpow==n */
    1203              :   {
    1204            0 :     ser = FlxqX_xi_norm(ser, MinPol2, p, d, upowuu(p, n));
    1205            0 :     ser = FlxX_to_Flx(ser);
    1206              :   }
    1207           56 :   pol = Flx_to_ZX(Flxn_Weierstrass_prep(ser, p, n, d_chi));
    1208           56 :   setvarn(pol, fetch_user_var("T"));
    1209              : #ifdef DEBUG
    1210              :   if (wd>0 && d_chi>1)
    1211              :     err_printf("(wd,d_chi,p,f,d,j,H)=(%ld,%ld,%ld,%ld,%ld,%ld,%Ps)\n",
    1212              :         wd,d_chi,p,f,d,j,gmael3(K, 1, 1, 1));
    1213              : #endif
    1214           56 :   return gc_GEN(av, pol);
    1215              : }
    1216              : 
    1217              : /* return 0 if lam_psi (psi=chi^j) is determined to be zero.
    1218              :  * else return -1.
    1219              :  * If psi(p)!=1, then N_{Q(zeta_d)/Q}(1-psi(p))!=0 (mod p) */
    1220              : static long
    1221        14504 : lam_chi_ber(GEN K, long p, long j)
    1222              : {
    1223        14504 :   pari_sp av = avma;
    1224        14504 :   GEN B1, B2, Chi = gel(K, 2), MinPol2 = gel(K, 7), B_num = gel(K, 8);
    1225        14504 :   long x, p2 = p*p, d = K_get_d(K), f = K_get_f(K);
    1226              : 
    1227        14504 :   if (f == d+1 && p == f && j == 1) return 0;  /* Teichmuller */
    1228              : 
    1229        14490 :   B1 = Flx_rem(Flx_ber_conj(B_num, j, d, p2), MinPol2, p2);
    1230        14490 :   B2 = Flx_rem(Flx_ber_den(Chi, j, d, p2), MinPol2, p2);
    1231        14490 :   if (degpol(B1)<0 || degpol(B2)<0)
    1232           49 :     return gc_long(av, -1); /* 0 mod p^2 */
    1233        14441 :   x = zx_lval(B1, p) - zx_lval(B2, p);
    1234        14441 :   if (x<0) pari_err_BUG("subcycloiwasawa [Bernoulli number]");
    1235        14441 :   return gc_long(av, x==0 ? 0: -1);
    1236              : }
    1237              : 
    1238              : static long
    1239          910 : lam_chi_xi(GEN K, long p, long j, long n)
    1240              : {
    1241          910 :   pari_sp av = avma;
    1242          910 :   GEN xi_conj, z, MinPol2 = gel(K, 7), xi = gel(K, 8);
    1243          910 :   long d = K_get_d(K), f = K_get_f(K), d_chi = K_get_dchi(K);
    1244          910 :   long wd, minpolpow = (f==p)?n+2:1, pm = upowuu(p, minpolpow);
    1245              : 
    1246              :   /* xi is FlxX mod p^m, MinPol2 is Flx mod p^m, xi_conj is FlxqX. */
    1247          910 :   xi_conj = FlxqX_xi_conj(xi, MinPol2, j, d, pm);
    1248          910 :   if (d_chi==1)  /* d_chi==1 if f==p */
    1249              :   {
    1250          686 :     xi_conj = FlxX_to_Flx(xi_conj);
    1251          686 :     if (f==p) xi_conj = zx_z_divexact(xi_conj, upowuu(p, n+1));
    1252              :   }
    1253              :   /* Now xi_conj is mod p^n */
    1254          686 :   z = (d_chi==1) ? Flxn_translate1(xi_conj, p, n)
    1255          910 :     : FlxXn_translate1(xi_conj, p, n);
    1256          910 :   wd = (d_chi==1)?Flx_weier_deg(z, p):FlxX_weier_deg(z, p);
    1257              : #ifdef DEBUG
    1258              :   if (wd>0 && d_chi>1)
    1259              :     err_printf("(wd,d_chi,p,f,d,j,H)=(%ld,%ld,%ld,%ld,%ld,%ld,%Ps)\n",
    1260              :         wd,d_chi,p,f,d,j,gmael3(K, 1, 1, 1));
    1261              : #endif
    1262          910 :   return gc_long(av, wd<0 ? -1 : wd*d_chi);
    1263              : }
    1264              : 
    1265              : /* K = [H1, Chi, Minpol, C, [d_chi, n_conj]] */
    1266              : static GEN
    1267           56 : imag_cyc_pol(GEN K, long p, long n)
    1268              : {
    1269           56 :   pari_sp av = avma;
    1270           56 :   GEN Chi = gel(K, 2), MinPol = gel(K, 3), C = gel(K, 4), MinPol2;
    1271           56 :   long d_K = K_get_d(K), f = K_get_f(K), n_conj = K_get_nconj(K);
    1272           56 :   long i, q0, pn1, pM, pmodf = p%f, n_done = 0;
    1273           56 :   GEN z = nullvec(), Gam, xi, Lam, K2;
    1274              : 
    1275           56 :   Lam = const_vecsmall(n_conj, -1);
    1276           56 :   if (pmodf==0 || Chi[pmodf]) /* mark trivial chi-part using Bernoulli number */
    1277              :   {
    1278           14 :     MinPol2 = ZX_to_Flx(MinPol, p*p);  /* p^2 for B_{1,chi} */
    1279           14 :     K2 = shallowconcat(K, mkvec2(MinPol2, zx_ber_num(Chi, f, d_K)));
    1280           42 :     for (i=1; i<=n_conj; i++)
    1281           28 :       if ((Lam[i] = lam_chi_ber(K2, p, C[i])) == 0) n_done++;
    1282           14 :     if (n_conj==n_done) return gc_GEN(av, z); /* all chi-parts trivial */
    1283              :   }
    1284           49 :   q0 = (f%p)? f*p: f;
    1285           49 :   pn1 = upowuu(p, n+1);
    1286           49 :   Gam = set_gam((1+q0)%pn1, p, n);
    1287           49 :   pM = upowuu(p, (f==p)? 2*n+1: n);
    1288           49 :   MinPol2 = ZX_to_Flx(MinPol, pM);
    1289            0 :   xi = (f==p)? get_xi_2(Chi, Gam, p, f, n, d_K, pM)
    1290           49 :              : get_xi_1(Chi, Gam, p, f, n, d_K, pM);
    1291           49 :   K2 = shallowconcat(K, mkvec2(MinPol2, xi));
    1292          105 :   for (i=1; i<=n_conj; i++)
    1293              :   {
    1294              :     GEN z1;
    1295           56 :     if (Lam[i]>=0) continue;
    1296           56 :     z1 = pol_chi_xi(K2, p, C[i], n);
    1297           56 :     if (degpol(z1)) z = vec_append(z, z1);  /* degpol(z1) may be zero */
    1298              :   }
    1299           49 :   return gc_GEN(av, z);
    1300              : }
    1301              : 
    1302              : /* K is an imaginary cyclic extension of degree d contained in Q(zeta_f)
    1303              :  * H is the subgr of G=(Z/fZ)^* corresponding to K
    1304              :  * h=|H|, d*h=phi(f)
    1305              :  * G/H=<g> i.e. g^d \in H
    1306              :  * d_chi=[Q_p(zeta_d):Q_p], i.e. p^d_chi=1 (mod d)
    1307              :  * An inj. char. of G(K/Q) is automatically imaginary.
    1308              :  *
    1309              :  * G(K/Q)=G/H=<g>, chi:G(K/Q) -> overline{Q_p} s.t. chi(g)=zeta_d^(-1)
    1310              :  * Chi[a]=k, k<0  => chi(a)=0
    1311              :  *           k>=0 => chi(a)=zeta_d^(-k)
    1312              :  * psi=chi^j, j in C : repre. of inj. odd char.
    1313              :  * psi(p)==1 <=> chi(p)^j==0 <=> j*Chi[p]=0 (mod d) <=> Chi[p]==0
    1314              :  *
    1315              :  * K = [H1, Chi, Minpol, C, [d_chi, n_conj]] */
    1316              : static long
    1317         3262 : imag_cyc_lam(GEN K, long p)
    1318              : {
    1319         3262 :   pari_sp av = avma;
    1320         3262 :   GEN Chi = gel(K, 2), MinPol = gel(K, 3), C = gel(K, 4), MinPol2;
    1321         3262 :   long d_K = K_get_d(K), f = K_get_f(K), n_conj = K_get_nconj(K);
    1322         3262 :   long i, q0, n, pmodf = p%f, n_done = 0;
    1323              :   ulong pn1, pM;
    1324         3262 :   GEN p0 = utoi(p), Gam, Lam, xi, K2;
    1325              : 
    1326         3262 :   q0 = (f%p)? f*p: f;
    1327         3262 :   Lam = const_vecsmall(n_conj, -1);
    1328         3262 :   if (pmodf==0 || Chi[pmodf])  /* 1st trial is Bernoulli number */
    1329              :   {
    1330         3052 :     MinPol2 = ZX_to_Flx(MinPol, p*p);  /* p^2 for B_{1,chi} */
    1331         3052 :     K2 = shallowconcat(K, mkvec2(MinPol2, zx_ber_num(Chi, f, d_K)));
    1332        17528 :     for (i=1; i<=n_conj; i++)
    1333        14476 :       if ((Lam[i] = lam_chi_ber(K2, p, C[i])) == 0) n_done++;
    1334         3052 :     if (n_conj==n_done) return gc_long(av, 0);  /* all chi-parts trivial */
    1335              :   }
    1336          413 :   pM = pn1 = p;
    1337          413 :   for (n=1; n>=0; n++)  /* 2nd trial is Stickelberger element */
    1338              :   {
    1339          413 :     pn1 *= p; /* p^(n+1) */
    1340          413 :     if (f == p)
    1341              :     { /* do not use set_minpol: it returns a new pol for each call */
    1342            0 :       GEN fac, cofac, v, pol = polcyclo(d_K, 0);
    1343            0 :       pM = pn1 * p; /* p^(n+2) */
    1344            0 :       fac = FpX_red(MinPol, p0); cofac = FpX_div(pol, fac, p0);
    1345            0 :       v = ZpX_liftfact(pol, mkvec2(fac, cofac), utoipos(pM), p0, n+2);
    1346            0 :       MinPol2 = gel(v, 1);
    1347              :     }
    1348          413 :     Gam = set_gam((1+q0)%pn1, p, n);
    1349          413 :     MinPol2 = ZX_to_Flx(MinPol, pM);
    1350            0 :     xi = (f==p)? get_xi_2(Chi, Gam, p, f, n, d_K, pM)
    1351          413 :                : get_xi_1(Chi, Gam, p, f, n, d_K, pM);
    1352          413 :     K2 = shallowconcat(K, mkvec2(MinPol2, xi));
    1353         2205 :     for (i=1; i<=n_conj; i++)
    1354         1792 :       if (Lam[i]<0 && (Lam[i] = lam_chi_xi(K2, p, C[i], n)) >= 0) n_done++;
    1355          413 :     if (n_conj==n_done) break;
    1356              :   }
    1357          413 :   return gc_long(av, zv_sum(Lam));
    1358              : }
    1359              : static GEN
    1360          329 : GHinit(long f, GEN HH, GEN *pcycGH)
    1361              : {
    1362          329 :   GEN G = znstar0(utoipos(f), 1);
    1363          329 :   GEN U, Ui, cycG, cycGH, ncycGH, gG, gGH, vChar, vH1, P, gH = gel(HH, 1);
    1364          329 :   long i, expG, n_f, lgH = lg(gH); /* gens. of H */
    1365          329 :   P = cgetg(lgH, t_MAT);
    1366          805 :   for (i = 1; i < lgH; i++) gel(P,i) = Zideallog(G, utoi(gH[i]));
    1367              : 
    1368              :   /* group structure of G/H */
    1369          329 :   cycG = znstar_get_cyc(G);
    1370          329 :   expG = itou(gel(cycG, 1));
    1371              :   /* gG generators of G, gGH generators of G/H: gGH = g.Ui, g = gGH.U */
    1372          329 :   cycGH = ZM_snf_group(hnfmodid(P, cycG), &U, &Ui);
    1373          329 :   ncycGH = cyc_normalize(cycGH);
    1374          329 :   gG = ZV_to_Flv(znstar_get_gen(G), f); /* gens. of G */
    1375              :   /* generators of G/H */
    1376          329 :   gGH = Flv_FlvV_factorback(gG, ZM_to_Flm(Ui, expG), f);
    1377          329 :   vChar = chargalois(cycGH, NULL); n_f = lg(vChar)-2;
    1378          329 :   vH1 = cgetg(n_f+1, t_VEC);
    1379        19124 :   for (i = 1; i <= n_f; i++)
    1380              :   { /* skip trivial character */
    1381        18795 :     GEN chi = gel(vChar,i+1), nchi = char_normalize(chi, ncycGH);
    1382        18795 :     GEN chiG, E, H1, C = gel(nchi, 2);
    1383        18795 :     long e, he, gen, d = itou(gel(nchi, 1));
    1384              :     /* chi(prod g[i]^e[i]) = e(sum e[i]*C[i] / d), chi has order d = #(G/H1)*/
    1385        18795 :     E = Flv_extgcd(C, d); /* \sum C[i]*E[i] = 1 in Z/dZ */
    1386              : 
    1387        18795 :     chiG = zncharlift(chi, ncycGH, U, cycG);
    1388        18795 :     H1 =  charker(cycG, chiG); /* H1 < G with G/H1 cyclic */
    1389        18795 :     e = itou( zncharconductor(G, chiG) ); /* cond H1 = cond chi */
    1390        18795 :     H1 = Flv_FlvV_factorback(zv_to_Flv(gG, e), ZM_to_Flm(H1, expG), e);
    1391        18795 :     gen = Flv_factorback(zv_to_Flv(gGH, e), E, e);
    1392        18795 :     H1 = znstar_generate(e, H1); /* G/H1 = <gen>, chi(gen) = e(1/d) */
    1393        18795 :     he = eulerphiu(e) / d;
    1394              :     /* G/H1 = <gen> cyclic of index d, e = cond(H1) */
    1395        18795 :     gel(vH1,i) = mkvec3(H1, mkvecsmall5(d,e,he,srh_1(H1), gen),
    1396              :                         subgp2ary(H1, he));
    1397              :   }
    1398          329 :   if (pcycGH) *pcycGH = cycGH;
    1399          329 :   return vH1;
    1400              : }
    1401              : 
    1402              : /* aH=g^iH ==> chi(a)=zeta_n^(-i); Chi[g^iH]=i; Chi[0] is never accessed */
    1403              : static GEN
    1404        13419 : get_chi(GEN H1)
    1405              : {
    1406        13419 :   GEN H = _get_H(H1);
    1407        13419 :   long i, j, gi, d = _get_d(H1), f = _get_f(H1), h = _get_h(H1), g = _get_g(H1);
    1408        13419 :   GEN Chi = const_vecsmall(f-1, -1);
    1409              : 
    1410      5584159 :   for (j=1; j<=h; j++) Chi[H[j]] = 0; /* i = 0 */
    1411       396592 :   for (i = 1, gi = g; i < d; i++)
    1412              :   {
    1413     40492081 :     for (j=1; j<=h; j++) Chi[Fl_mul(gi, H[j], f)] = i;
    1414       383173 :     gi = Fl_mul(gi, g, f);
    1415              :   }
    1416        13419 :   return Chi;
    1417              : }
    1418              : 
    1419              : static void
    1420           14 : errpdiv(const char *f, GEN p, long d)
    1421              : {
    1422           14 :   pari_err_DOMAIN(f, "p", "divides",
    1423           14 :                   strtoGENstr(stack_sprintf("[F:Q] = %ld", d)), p);
    1424            0 : }
    1425              : /* p odd doesn't divide degF; return lambda invariant if n==0 and
    1426              :  * iwasawa polynomials if n>=1 */
    1427              : static GEN
    1428           49 : abeliwasawa(long p, long f, GEN HH, long degF, long n)
    1429              : {
    1430           49 :   long lam = 0, i, n_f;
    1431           49 :   GEN vH1, vData, z = nullvec(), p0 = utoi(p) ;
    1432              : 
    1433           49 :   vH1 = GHinit(f, HH, NULL); n_f = lg(vH1)-1;
    1434           49 :   vData = const_vec(degF, NULL);
    1435         6608 :   for (i=1; i<=n_f; i++) /* prescan. set Teichmuller */
    1436              :   {
    1437         6573 :     GEN H1 = gel(vH1,i);
    1438         6573 :     long d_K = _get_d(H1), f_K = _get_f(H1), g_K = _get_g(H1);
    1439              : 
    1440         6573 :     if (f_K == d_K+1 && p == f_K)  /* found K=Q(zeta_p) */
    1441              :     {
    1442           14 :       long d_chi = 1, n_conj = eulerphiu(d_K);
    1443           14 :       GEN C = set_C(p, d_K, d_chi, n_conj);
    1444           14 :       long minpow = n? 2*n+1: 2;
    1445           14 :       GEN MinPol = set_minpol_teich(g_K, p0, minpow);
    1446           14 :       gel(vData, d_K) = mkvec4(MinPol, C, NULL, mkvecsmall2(d_chi, n_conj));
    1447           14 :       break;
    1448              :     }
    1449              :   }
    1450              : 
    1451         6664 :   for (i=1; i<=n_f; i++)
    1452              :   {
    1453         6615 :     GEN H1 = gel(vH1,i), z1, Chi, K;
    1454         6615 :     long d_K = _get_d(H1), s = _get_s(H1);
    1455              : 
    1456         6615 :     if (s) continue;  /* F is real */
    1457              : #ifdef DEBUG
    1458              :     err_printf("  handling %s cyclic subfield K, deg(K)=%ld, cond(K)=%ld\n",
    1459              :         s? "a real": "an imaginary", d_K, _get_f(H1));
    1460              : #endif
    1461         3318 :     if (!gel(vData, d_K))
    1462              :     {
    1463          126 :       long d_chi = order_f_x(d_K, p), n_conj = eulerphiu(d_K)/d_chi;
    1464          126 :       GEN C = set_C(p, d_K, d_chi, n_conj);
    1465          126 :       long minpow = n? n+1: 2;
    1466          126 :       GEN MinPol = set_minpol(d_K, p0, minpow, n_conj);
    1467          126 :       gel(vData, d_K) = mkvec4(MinPol, C, NULL, mkvecsmall2(d_chi, n_conj));
    1468              :     }
    1469         3318 :     Chi = get_chi(H1);
    1470         3318 :     K = shallowconcat(mkvec2(H1, Chi), gel(vData, d_K));
    1471         3318 :     if (n==0) lam += imag_cyc_lam(K, p);
    1472           56 :     else if (lg(z1 = imag_cyc_pol(K, p, n)) > 1) z = shallowconcat(z, z1);
    1473              :   }
    1474           49 :   return n? z: mkvecs(lam);
    1475              : }
    1476              : 
    1477              : static GEN
    1478           77 : ary2mat(GEN x, long n)
    1479              : {
    1480              :   long i, j;
    1481           77 :   GEN z = cgetg(n+1,t_MAT);
    1482          182 :   for (i=1; i<=n; i++)
    1483              :   {
    1484          105 :     gel(z,i) = cgetg(n+1,t_COL);
    1485          280 :     for (j=1; j<=n; j++) gmael(z, i, j) = utoi(x[(i-1)*n+j-1]);
    1486              :   }
    1487           77 :   return z;
    1488              : }
    1489              : 
    1490              : static long
    1491            0 : is_cyclic(GEN x)
    1492              : {
    1493            0 :   GEN y = gel(x, 2);
    1494            0 :   long i, l = lg(y), n = 0;
    1495            0 :   for (i = 1; i < l; i++) if (signe(gel(y,i))) n++;
    1496            0 :   return n <= 1;
    1497              : }
    1498              : 
    1499              : static GEN
    1500           77 : make_p_part(GEN y, ulong p, long d_pow)
    1501              : {
    1502           77 :   long i, l = lg(y);
    1503           77 :   GEN z = cgetg(l, t_VECSMALL);
    1504          182 :   for (i = 1; i < l; i++) z[i] = signe(gel(y,i))? Z_lval(gel(y,i), p): d_pow;
    1505           77 :   return z;
    1506              : }
    1507              : 
    1508              : static GEN
    1509           77 : structure_MLL(GEN y, long d_pow)
    1510              : {
    1511           77 :   long y0, i, l = lg(y);
    1512           77 :   GEN x = gen_0, E = cgetg(l, t_VEC);
    1513          182 :   for (i = 1; i < l; i++)
    1514              :   {
    1515          105 :     if ((y0 = d_pow-y[i]) < 0) y0 = 0;
    1516          105 :     x = addiu(x, y0);
    1517          105 :     gel(E, l-i) = utoi(y0);
    1518              :   }
    1519           77 :   return mkvec2(x, E);
    1520              : }
    1521              : 
    1522              : static long
    1523           14 : find_del_el(GEN *oldgr, GEN newgr, long n, long n_el, long d_chi)
    1524              : {
    1525           14 :   if (n_el==1) return 1;
    1526           14 :   if (equalis(gmael(newgr, 2, 1), n_el)) return n;
    1527           14 :   if (cmpii(gel(*oldgr, 1), gel(newgr, 1)) >= 0) return n;
    1528           14 :   if (n > 1 && is_cyclic(newgr)) { *oldgr = newgr; return n-1; }
    1529           14 :   if (n == n_el) return n;
    1530           14 :   if (cmpis(gel(newgr, 1), n*d_chi) < 0) return n;
    1531           14 :   return 0;
    1532              : }
    1533              : 
    1534              : static GEN
    1535            7 : subgr2vecsmall(GEN H, long h, long f)
    1536              : {
    1537              :   long i;
    1538            7 :   GEN z = const_vecsmall(f-1, 0); /* f=lg(z) */
    1539         2023 :   for (i=1; i<=h; i++) z[H[i]] = 1; /* H[i]!=0 */
    1540            7 :   return z;
    1541              : }
    1542              : 
    1543              : /* K is the subfield of Q(zeta_f) with degree d corresponding to the subgroup
    1544              :  * H in (Z/fZ)^*; for a divisor e of f, zeta_e \in K <=> H \subset He. */
    1545              : static long
    1546          119 : root_of_1(long f, GEN H)
    1547              : {
    1548          119 :   GEN g = gel(H, 1); /* generators */
    1549          119 :   long e = f, i, l = lg(g);
    1550          119 :   for (i = 1; i < l; i++)
    1551              :   {
    1552           98 :     e = cgcd(e, g[i] - 1);
    1553           98 :     if (e <= 2) return 2;
    1554              :   }
    1555           21 :   return odd(e)? (e<<1): e;
    1556              : }
    1557              : 
    1558              : static long
    1559          259 : find_ele(GEN H)
    1560              : {
    1561          259 :   long i, f=lg(H);
    1562       369852 :   for (i=1; i<f; i++) if (H[i]) return i;
    1563            7 :   return 0;
    1564              : }
    1565              : 
    1566              : static void
    1567          252 : delete_ele(GEN H, long j, long el)
    1568              : {
    1569          252 :   long f = lg(H), x = 1;
    1570         2016 :   do H[Fl_mul(j,x,f)] = 0;
    1571         2016 :   while ((x=Fl_mul(x,el,f))!=1);
    1572          252 : }
    1573              : 
    1574              : static GEN
    1575            7 : get_coset(GEN H, long h, long f, long el)
    1576              : {
    1577            7 :   long i, j, k = h/order_f_x(f, el);
    1578            7 :   GEN H2, coset = const_vecsmall(k, 0);
    1579            7 :   H2 = subgr2vecsmall(H, h, f);
    1580          259 :   for (i=0; (j=find_ele(H2))>0; i++)
    1581              :   {
    1582          252 :     coset[1+i] = j;
    1583          252 :     delete_ele(H2, j, el);
    1584              :   }
    1585            7 :   if (i != k) pari_err_BUG("failed to find coset\n");
    1586            7 :   return coset;
    1587              : }
    1588              : 
    1589              : static long
    1590         3024 : srh_pol(GEN xpows, GEN vn, GEN pols, long el, long k, long f)
    1591              : {
    1592         3024 :   pari_sp av = avma;
    1593         3024 :   long i, j, l = lg(pols), d = degpol(gel(pols, 1));
    1594         3024 :   GEN pol = gel(pols, 1);
    1595              : 
    1596       654696 :   for (i=1; i<l; i++)
    1597              :   {
    1598              :     GEN x, y, z;
    1599       654696 :     if (vn[i]==0) continue;
    1600       331170 :     y = gel(pols, vn[i]);
    1601       331170 :     z = pol0_Flx(0);
    1602      3311700 :     for (j=0; j<=d; j++)
    1603      2980530 :       z = Flx_add(z, Flx_Fl_mul(gel(xpows, 1+Fl_mul(j, k, f)), y[2+j], el), el);
    1604       331170 :     x = Flx_rem(z, pol, el);
    1605       331170 :     if (lg(x)==2)
    1606         3024 :     {vn[i] = 0; return gc_long(av, i); }  /* pols[i] is min pol of zeta_f^k */
    1607              :   }
    1608            0 :   pari_err_BUG("subcyclopclgp [minimal polinomial]");
    1609            0 :   return 0;  /* to suppress warning */
    1610              : }
    1611              : 
    1612              : /* e_chi[i mod dK] = chi(i*j), i = 0..dK-1; beware: e_chi is translated ! */
    1613              : static GEN
    1614        35857 : get_e_chi(GEN K, ulong j, ulong d, ulong *pdK)
    1615              : {
    1616        35857 :   ulong i, dK = K_get_d(K);
    1617        35857 :   GEN TR = gel(K,4) + 2, e_chi = cgetg(dK+1, t_VECSMALL) + 1;
    1618        35857 :   if (j == 1)
    1619       286902 :     for (i = 0; i < dK; i++) e_chi[i] = umodiu(gel(TR, i), d);
    1620              :   else
    1621       983345 :     for (i = 0; i < dK; i++) e_chi[i] = umodiu(gel(TR, Fl_mul(i, j, dK)), d);
    1622        35857 :   *pdK = dK; return e_chi;
    1623              : }
    1624              : static GEN
    1625         5145 : get_e_chi_ll(GEN K, ulong j, GEN d)
    1626              : {
    1627         5145 :   ulong i, dK = umael3(K, 1, 2, 1);
    1628         5145 :   GEN TR = gel(K,4) + 2, e_chi = cgetg(dK+1, t_VEC) + 1;
    1629       246785 :   for (i = 0; i < dK; i++) gel(e_chi,i) = modii(gel(TR, Fl_mul(i, j, dK)), d);
    1630         5145 :   return e_chi;
    1631              : }
    1632              : 
    1633              : /* el=1 (mod f) */
    1634              : static long
    1635            0 : chk_el_real_f(GEN K, ulong p, ulong d_pow, ulong el, ulong j0)
    1636              : {
    1637            0 :   pari_sp av = avma;
    1638            0 :   GEN H = K_get_H(K);
    1639            0 :   ulong d_K, f = K_get_f(K), h = K_get_h(K), g_K = K_get_g(K);
    1640            0 :   ulong  i, j, gi, d = upowuu(p, d_pow), dp = d*p;
    1641            0 :   ulong g_el, z_f, flag = 0, el1f = (el-1)/f, el1dp = (el-1)/dp;
    1642            0 :   GEN e_chi = get_e_chi(K, j0, dp, &d_K);
    1643            0 :   GEN vz_f, xi_el = cgetg(d_K+1, t_VECSMALL)+1;
    1644              : 
    1645            0 :   g_el = pgener_Fl(el);
    1646            0 :   z_f = Fl_powu(g_el, el1f, el);
    1647            0 :   vz_f = Fl_powers(z_f, f-1, el)+1;
    1648              : 
    1649            0 :   for (gi = 1, i = 0; i < d_K; i++)
    1650              :   {
    1651            0 :     ulong x = 1;
    1652            0 :     for (j = 1; j <= h; j++)
    1653              :     {
    1654            0 :       ulong y = Fl_mul(H[j], gi, f);
    1655            0 :       x = Fl_mul(x, vz_f[y]-1, el); /* vz_f[y] = z_f^y  */
    1656              :     }
    1657            0 :     gi = Fl_mul(gi, g_K, f);
    1658            0 :     xi_el[i] = x;  /* xi_el[i] = xi^{g_K^i} mod el */
    1659              :   }
    1660            0 :   for (i=0; i<d_K; i++)
    1661              :   {
    1662            0 :     ulong x = 1;
    1663            0 :     for (j=0; j<d_K; j++)
    1664            0 :       x = Fl_mul(x, Fl_powu(xi_el[j], e_chi[(i+j)%d_K], el), el);
    1665            0 :     if ((x = Fl_powu(x, el1dp, el))!=1) flag = 1;
    1666            0 :     if (Fl_powu(x, p, el)!=1) return gc_long(av,0);
    1667              :   }
    1668            0 :   return gc_long(av, flag?1:0);
    1669              : }
    1670              : 
    1671              : /* For a cyclic field K contained in Q(zeta_f),
    1672              :  * computes minimal polynomial T of theta=Tr_{Q(zeta_f)/K}(zeta_f) over Q
    1673              :  * and conjugates of theta */
    1674              : static GEN
    1675           14 : minpol_theta(GEN K)
    1676              : {
    1677           14 :   GEN HH = gmael3(K,1,1,1);
    1678           14 :   return galoissubcyclo(utoi(K_get_f(K)), HH, 0, 0);
    1679              : }
    1680              : 
    1681              : /*  xi[1+i] = i-th conj of xi = Tr_{Q(zeta_f)/K}(1-zeta_f).
    1682              :  * |1-(cos(x)+i*sin(x))|^2 = 2(1-cos(x)) */
    1683              : static GEN
    1684            0 : xi_approx(GEN K, long prec)
    1685              : {
    1686            0 :   pari_sp av = avma;
    1687            0 :   GEN H = K_get_H(K);
    1688            0 :   long d_K = K_get_d(K), f = K_get_f(K), h = K_get_h(K), g_K = K_get_g(K);
    1689            0 :   GEN xi = cgetg(d_K+1, t_COL), vz_f = grootsof1(f, prec);
    1690            0 :   long i, j, g = 1, h2 = h>>1;
    1691            0 :   for (i=1; i<=d_K; i++)
    1692              :   {
    1693            0 :     GEN y = real_1(prec);
    1694            0 :     for (j=1; j<=h2; j++)
    1695              :     {
    1696            0 :       GEN z = gmael(vz_f, 1+Fl_mul(H[j], g, f), 1);
    1697            0 :       y = mulrr(y, shiftr(subsr(1, z), 1));
    1698              :     }
    1699            0 :     gel(xi, i) = y;
    1700            0 :     g = Fl_mul(g, g_K, f);
    1701              :   }
    1702            0 :   return gc_GEN(av, xi);
    1703              : }
    1704              : 
    1705              : static GEN
    1706           47 : theta_xi_el(GEN K, ulong el)
    1707              : {
    1708           47 :   pari_sp av = avma;
    1709           47 :   GEN H = K_get_H(K);
    1710           47 :   ulong d_K = K_get_d(K), f = K_get_f(K), h = K_get_h(K), g_K = K_get_g(K);
    1711           47 :   GEN theta = cgetg(d_K+1, t_VECSMALL), xi = cgetg(d_K+1, t_VECSMALL), vz_f;
    1712           47 :   ulong i, j, g = 1, x, y, g_el, z_f;
    1713              : 
    1714           47 :   g_el = pgener_Fl(el);
    1715           47 :   z_f = Fl_powu(g_el, (el-1)/f, el);
    1716           47 :   vz_f = Fl_powers(z_f, f-1, el);
    1717         1109 :   for (i=1; i<=d_K; i++)
    1718              :   {
    1719         1062 :     x = 0; y = 1;
    1720        28254 :     for (j=1; j<=h; j++)
    1721              :     {
    1722        27192 :       ulong z = vz_f[1+Fl_mul(H[j], g, f)];
    1723        27192 :       x = Fl_add(x, z, el);
    1724        27192 :       y = Fl_mul(y, z-1, el);
    1725              :     }
    1726         1062 :     theta[i] = x;
    1727         1062 :     xi[i] = y;
    1728         1062 :     g = Fl_mul(g, g_K, f);
    1729              :   }
    1730           47 :   return gc_GEN(av, mkvec2(theta, xi));
    1731              : }
    1732              : 
    1733              : static GEN
    1734           47 : make_Xi(GEN xi, long d)
    1735              : {
    1736              :   long i, j;
    1737           47 :   GEN Xi = cgetg(d+1, t_MAT);
    1738         1109 :   for (j=0; j<d; j++)
    1739              :   {
    1740         1062 :     GEN x = cgetg(d+1, t_VECSMALL);
    1741         1062 :     gel(Xi, 1+j) = x;
    1742        27714 :     for (i=0; i<d; i++) x[1+i] = xi[1+(i+j)%d];
    1743              :   }
    1744           47 :   return Xi;
    1745              : }
    1746              : 
    1747              : static GEN
    1748           47 : make_Theta(GEN theta, ulong d, ulong el)
    1749              : {
    1750              :   ulong i;
    1751           47 :   GEN Theta = cgetg(d+1, t_MAT);
    1752         1109 :   for (i=1; i<=d; i++) gel(Theta, i) = Fl_powers(theta[i], d-1, el);
    1753           47 :   return Flm_inv(Theta, el);
    1754              : }
    1755              : 
    1756              : static GEN
    1757           47 : Xi_el(GEN K, GEN tInvA, ulong el)
    1758              : {
    1759           47 :   pari_sp av = avma;
    1760           47 :   ulong d_K = K_get_d(K);
    1761           47 :   GEN tx = theta_xi_el(K, el), Theta, Xi, X;
    1762              : 
    1763           47 :   if ((Theta = make_Theta(gel(tx, 1), d_K, el))==NULL) return NULL;
    1764           47 :   Xi = make_Xi(gel(tx, 2), d_K);
    1765           47 :   X = Flm_mul(Flm_mul(Xi, Theta, el), ZM_to_Flm(tInvA, el), el);
    1766           47 :   return gc_GEN(av, X);
    1767              : }
    1768              : 
    1769              : static GEN
    1770            0 : pol_xi_el(GEN K, ulong el)
    1771              : {
    1772            0 :   pari_sp av = avma;
    1773            0 :   ulong d_K = K_get_d(K), f = K_get_f(K), h = K_get_h(K), g_K = K_get_g(K);
    1774            0 :   GEN H = K_get_H(K), xi = cgetg(d_K+1, t_VECSMALL), vz_f;
    1775            0 :   ulong i, j, g = 1, y, g_el, z_f;
    1776              : 
    1777            0 :   g_el = pgener_Fl(el);
    1778            0 :   z_f = Fl_powu(g_el, (el-1)/f, el);
    1779            0 :   vz_f = Fl_powers(z_f, f-1, el);
    1780            0 :   for (i=1; i<=d_K; i++)
    1781              :   {
    1782            0 :     y = 1;
    1783            0 :     for (j=1; j<=h; j++)
    1784              :     {
    1785            0 :       ulong z = vz_f[1+Fl_mul(H[j], g, f)];
    1786            0 :       y = Fl_mul(y, z-1, el);
    1787              :     }
    1788            0 :     xi[i] = y;
    1789            0 :     g = Fl_mul(g, g_K, f);
    1790              :   }
    1791            0 :   return gc_GEN(av, Flv_roots_to_pol(xi, el, 0));
    1792              : }
    1793              : 
    1794              : /* theta[1+i] = i-th conj of theta; xi[1+i] = i-th conj of xi. */
    1795              : static GEN
    1796           14 : theta_xi_approx(GEN K, long prec)
    1797              : {
    1798           14 :   pari_sp av = avma;
    1799           14 :   GEN H = K_get_H(K);
    1800           14 :   long d_K = K_get_d(K), f = K_get_f(K), h = K_get_h(K), g_K = K_get_g(K);
    1801           14 :   GEN theta = cgetg(d_K+1, t_VEC), xi = cgetg(d_K+1, t_VEC);
    1802           14 :   GEN vz_f = grootsof1(f, prec);
    1803           14 :   long i, j, g = 1, h2 = h>>1;
    1804              : 
    1805          238 :   for (i=1; i<=d_K; i++)
    1806              :   {
    1807          224 :     GEN x = real_0(prec), y = real_1(prec);
    1808         5068 :     for (j=1; j<=h2; j++)
    1809              :     {
    1810         4844 :       GEN z = gmael(vz_f, 1+Fl_mul(H[j], g, f), 1);
    1811         4844 :       x = addrr(x, z);
    1812         4844 :       y = mulrr(y, shiftr(subsr(1, z), 1));
    1813              :     }
    1814          224 :     gel(theta, i) = shiftr(x, 1);
    1815          224 :     gel(xi, i) = y;
    1816          224 :     g = Fl_mul(g, g_K, f);
    1817              :   }
    1818           14 :   return gc_GEN(av, mkvec2(theta, xi));
    1819              : }
    1820              : 
    1821              : static GEN
    1822           14 : bound_coeff_xi(GEN K, GEN tInvA)
    1823              : {
    1824           14 :   pari_sp av = avma;
    1825           14 :   long d_K = K_get_d(K), prec = MEDDEFAULTPREC, i;
    1826           14 :   GEN tInvV, R = cgetg(d_K+1, t_MAT), theta_xi = theta_xi_approx(K, prec);
    1827           14 :   GEN theta = gel(theta_xi, 1), xi = gel(theta_xi, 2), x1, x2, bound;
    1828              : 
    1829          238 :   for (i=1; i<=d_K; i++)
    1830              :   {
    1831          224 :     GEN z = gpowers(gel(theta, i), d_K-1);
    1832          224 :     settyp(z, t_COL);
    1833          224 :     gel(R, i) = z;
    1834              :   }
    1835           14 :   tInvV = RgM_mul(RgM_inv(R), tInvA);
    1836           14 :   x1 = gsupnorm(tInvV, prec); x2 = gsupnorm(xi, prec);
    1837           14 :   bound = mulrs(mulrr(x1, x2), 3*d_K);
    1838           14 :   return gc_GEN(av, bound);
    1839              : }
    1840              : 
    1841              : static GEN
    1842           14 : get_Xi(GEN K, GEN tInvA)
    1843              : {
    1844           14 :   pari_sp av = avma;
    1845              :   GEN M0, XI, EL, Xi;
    1846           14 :   ulong f = K_get_f(K), el, e, n, i;
    1847              :   forprime_t T0;
    1848              : 
    1849           14 :   M0 = bound_coeff_xi(K, tInvA);
    1850           14 :   e = expo(M0)+1; n = e/(BITS_IN_LONG-1); n++;
    1851           14 :   EL = cgetg(1+n, t_VECSMALL);
    1852           14 :   XI = cgetg(1+n, t_VEC);
    1853           14 :   u_forprime_arith_init(&T0, LONG_MAX, ULONG_MAX, 1, f);
    1854              : 
    1855           61 :   for (i=1; i<=n; i++)
    1856              :   {
    1857           47 :     el = u_forprime_next(&T0);
    1858           47 :     while ((Xi=Xi_el(K, tInvA, el))==NULL) el = u_forprime_next(&T0);
    1859           47 :     gel(XI, i) = Xi;
    1860           47 :     EL[i] = el;
    1861              :   }
    1862           14 :   return gc_upto(av, nmV_chinese_center(XI, EL, NULL));
    1863              : }
    1864              : 
    1865              : /* K is a cyclic field of conductor f with degree d=d_K
    1866              :  * xi = Norm_{Q(zeta_f)/K}(1-zeta_f)
    1867              :  * 1: T, min poly of a=Tr_{Q(zeta_f)/K}(zeta_f) over Q
    1868              :  * 2: B, power basis of K with respect to a
    1869              :  * 3: A, rational matrix s.t. t(v_1,...v_d) = A*t(1,a,...,a^{d-1})
    1870              :  * 4: Xi, integer matrix s.t. t(xi^(1),...,xi^(d)) = Xi*t(v_1,...,v_d) */
    1871              : static GEN
    1872           14 : xi_data_basis(GEN K)
    1873              : {
    1874           14 :   pari_sp av = avma;
    1875           14 :   GEN T = minpol_theta(K);
    1876              :   GEN InvA, A, M, Xi, A_den;
    1877           14 :   GEN D, B = nfbasis(T, &D);
    1878              :   pari_timer ti;
    1879           14 :   if (DEBUGLEVEL>1) timer_start(&ti);
    1880           14 :   A = RgXV_to_RgM(B, lg(B)-1);
    1881           14 :   M = gmael(A, 1, 1);
    1882           14 :   if (!equali1(M)) A = RgM_Rg_div(A, M);
    1883           14 :   InvA = QM_inv(A);
    1884           14 :   A = Q_remove_denom(A, &A_den);
    1885           14 :   if (A_den==NULL) A_den = gen_1;
    1886           14 :   Xi = get_Xi(K, shallowtrans(InvA));
    1887           14 :   if (DEBUGLEVEL>1) timer_printf(&ti, "xi_data_basis");
    1888           14 :   return gc_GEN(av, mkvec5(T, B, shallowtrans(A), Xi, A_den));
    1889              : }
    1890              : 
    1891              : /* When factorization of polcyclo mod el is difficult, one can try to
    1892              :  * check the condition of el using an integral basis of K.
    1893              :  * This is useful when d_K is small. */
    1894              : static long
    1895           14 : chk_el_real_basis(GEN K, long p, long d_pow, long el, long j0)
    1896              : {
    1897           14 :   pari_sp av = avma;
    1898           14 :   GEN xi = gel(K, 7), T = gel(xi, 1), A = gel(xi, 3), Xi = gel(xi, 4);
    1899           14 :   GEN A_den = gel(xi, 5);
    1900           14 :   ulong i, j, x, found = 0;
    1901              :   GEN v_el, xi_el;
    1902              :   GEN e_chi, xi_e_chi;
    1903              :   ulong d_K, d, dp, el1dp;
    1904              : 
    1905           14 :   if (dvdiu(A_den, el)) return 0;
    1906              : 
    1907           14 :   d = upowuu(p, d_pow); dp = d*p; el1dp = (el-1)/dp;
    1908           14 :   e_chi = get_e_chi(K, j0, dp, &d_K);
    1909           14 :   xi_e_chi = cgetg(d_K+1, t_VECSMALL)+1;
    1910              : 
    1911           14 :   if (DEBUGLEVEL>1) err_printf("chk_el_real_basis: d_K=%ld el=%ld\n",d_K,el);
    1912           14 :   A = ZM_to_Flm(A, el);
    1913           14 :   A = Flm_Fl_mul(A, Fl_inv(umodiu(A_den, el), el), el);
    1914           14 :   x = Flx_oneroot_split(ZX_to_Flx(T, el), el);
    1915           14 :   v_el = Flm_Flc_mul(A, Fl_powers(x, d_K-1, el), el);
    1916           14 :   xi_el = Flm_Flc_mul(ZM_to_Flm(Xi, el), v_el, el);
    1917           14 :   if (DEBUGLEVEL>2) err_printf("el=%ld xi_el=%Ps\n", el, xi_el);
    1918          238 :   for (i=0; i<d_K; i++)
    1919              :   {
    1920          224 :     long z = 1;
    1921         5208 :     for (j=0; j<d_K; j++)
    1922         4984 :       z = Fl_mul(z, Fl_powu(xi_el[1+j], e_chi[(i+j)%d_K], el), el);
    1923          224 :     xi_e_chi[i] = z;
    1924              :   }
    1925           14 :   if (DEBUGLEVEL>2) err_printf("xi_e_chi=%Ps\n", xi_e_chi-1);
    1926          238 :   for (i=0; i<d_K; i++)
    1927              :   {
    1928          224 :     long x = Fl_powu(xi_e_chi[i], el1dp, el);
    1929          224 :     if (x!=1) found = 1;
    1930          224 :     if (Fl_powu(x, p, el)!=1) return gc_long(av, 0);
    1931              :   }
    1932           14 :   return gc_long(av, found);
    1933              : }
    1934              : 
    1935              : static GEN
    1936            0 : bound_pol_xi(GEN K)
    1937              : {
    1938            0 :   pari_sp av = avma;
    1939            0 :   GEN xi = xi_approx(K, MEDDEFAULTPREC);
    1940            0 :   GEN M = real_1(MEDDEFAULTPREC), one = rtor(dbltor(1.0001), MEDDEFAULTPREC);
    1941            0 :   long i, n = lg(xi);
    1942              : 
    1943            0 :   for (i=1; i<n; i++) M = mulrr(M, addrr(one, gel(xi, i)));
    1944            0 :   M = mulrs(M, 3);
    1945            0 :   return gc_GEN(av, M);
    1946              : }
    1947              : 
    1948              : static GEN
    1949            0 : minpol_xi(GEN K)
    1950              : {
    1951            0 :   pari_sp av = avma;
    1952              :   GEN M0, POL, EL;
    1953            0 :   ulong f = K_get_f(K), el, e, n, i;
    1954              :   forprime_t T0;
    1955              : 
    1956            0 :   M0 = bound_pol_xi(K);
    1957            0 :   e = expo(M0)+1; n = e/(BITS_IN_LONG-1); n++;
    1958            0 :   EL = cgetg(1+n, t_VECSMALL);
    1959            0 :   POL = cgetg(1+n, t_VEC);
    1960            0 :   u_forprime_arith_init(&T0, LONG_MAX, ULONG_MAX, 1, f);
    1961            0 :   for (i=1; i<=n; i++)
    1962              :   {
    1963            0 :     el = u_forprime_next(&T0);
    1964            0 :     gel(POL, i) = pol_xi_el(K, el);
    1965            0 :     EL[i] = el;
    1966              :   }
    1967            0 :   return gc_upto(av, nxV_chinese_center(POL, EL, NULL));
    1968              : }
    1969              : 
    1970              : static long
    1971            0 : find_conj_el(GEN K, GEN pol, GEN Den)
    1972              : {
    1973            0 :   pari_sp av = avma;
    1974            0 :   GEN H = K_get_H(K);
    1975            0 :   ulong d_K = K_get_d(K), f = K_get_f(K), h = K_get_h(K), g = K_get_g(K);
    1976            0 :   ulong j, k, el, g_el, z_f, xi = 1, xi_g = 1;
    1977            0 :   GEN T = NULL, vz_f;
    1978              : 
    1979            0 :   for (el=f+1; el; el+=f)
    1980            0 :     if (uisprime(el) && dvdiu(Den, el)==0)
    1981              :     {
    1982            0 :       T = ZX_to_Flx(pol, el);
    1983            0 :       T = Flx_Fl_mul(T, Fl_inv(umodiu(Den, el), el), el);
    1984            0 :       break;
    1985              :     }
    1986            0 :   g_el = pgener_Fl(el);
    1987            0 :   z_f = Fl_powu(g_el, (el-1)/f, el);
    1988            0 :   vz_f = Fl_powers(z_f, f-1, el);
    1989            0 :   for (j=1; j<=h; j++)
    1990            0 :     xi = Fl_mul(xi, vz_f[1+H[j]]-1, el);
    1991            0 :   for (j=1; j<=h; j++)
    1992            0 :     xi_g = Fl_mul(xi_g, vz_f[1+Fl_mul(H[j], g, f)]-1, el);
    1993            0 :   for (k=1; k<=d_K; k++)
    1994              :   {
    1995            0 :     xi = Flx_eval(T, xi, el);
    1996            0 :     if (xi == xi_g) break;
    1997              :   }
    1998            0 :   if (xi != xi_g) pari_err_BUG("find_conj_el");
    1999            0 :   return gc_long(av, k);
    2000              : }
    2001              : 
    2002              : /* G = H_1*H_2*...*H_m is cyclic of order n, H_i=<perms[i]>
    2003              :  * G is not necessarily a direct product.
    2004              :  * If p^e || n, then p^e || |H_i| for some i.
    2005              :  * return a generator of G. */
    2006              : static GEN
    2007            0 : find_gen(GEN perms, long n)
    2008              : {
    2009            0 :   GEN fa = factoru(n), P = gel(fa, 1), E = gel(fa, 2);
    2010            0 :   long i, j, l = lg(perms), r = lg(P);
    2011            0 :   GEN gen = cgetg(r, t_VEC), orders = cgetg(l, t_VECSMALL), perm;
    2012              : 
    2013            0 :   for (i=1; i<l; i++) orders[i] = perm_orderu(gel(perms, i));
    2014            0 :   for (i=1; i<r; i++)
    2015              :   {
    2016            0 :     long pe = upowuu(P[i], E[i]);
    2017            0 :     for (j=1; j<l; j++) if (orders[j]%pe==0) break;
    2018            0 :     gel(gen, i) = perm_powu(gel(perms, j), orders[j]/pe);
    2019              :   }
    2020            0 :   perm = gel(gen, 1);
    2021            0 :   for (i=2; i<l; i++) perm = perm_mul(perm, gel(gen, i));
    2022            0 :   return perm;
    2023              : }
    2024              : 
    2025              : /* R is the roots of T. R[1+i] = R[1]^(g_K^i), 0 <= i <= d_K-1
    2026              :  * 1: min poly T of xi over Q
    2027              :  * 2: F(x)\in Q[x] s.t. xi^(g_K)=F(xi) */
    2028              : static GEN
    2029            0 : xi_data_galois(GEN K)
    2030              : {
    2031            0 :   pari_sp av = avma;
    2032              :   GEN T, G, perms, perm, pol, pol2, Den;
    2033            0 :   ulong k, d_K = K_get_d(K);
    2034              :   pari_timer ti;
    2035              : 
    2036            0 :   if (DEBUGLEVEL>1) timer_start(&ti);
    2037            0 :   T = minpol_xi(K);
    2038            0 :   if (DEBUGLEVEL>1) timer_printf(&ti, "minpol_xi");
    2039            0 :   G = galoisinit(T, NULL);
    2040            0 :   if (DEBUGLEVEL>1) timer_printf(&ti, "galoisinit");
    2041            0 :   perms = gal_get_gen(G);
    2042            0 :   perm = (lg(perms)==2)?gel(perms, 1):find_gen(perms, d_K);
    2043            0 :   if (DEBUGLEVEL>1) timer_start(&ti);
    2044            0 :   pol = galoispermtopol(G, perm);
    2045            0 :   if (DEBUGLEVEL>1) timer_printf(&ti, "galoispermtopol");
    2046            0 :   pol = Q_remove_denom(pol, &Den);
    2047            0 :   if (Den==NULL) Den = gen_1;
    2048            0 :   k = find_conj_el(K, pol, Den);
    2049            0 :   if (DEBUGLEVEL>1) timer_printf(&ti,"find_conj");
    2050            0 :   pol2 = galoispermtopol(G, perm_powu(perm, k));
    2051            0 :   pol2 = Q_remove_denom(pol2, &Den);
    2052            0 :   if (Den==NULL) Den = gen_1;
    2053            0 :   return gc_GEN(av, mkvec3(T, pol2, Den));
    2054              : }
    2055              : 
    2056              : /* If g(X)\in Q[X] s.t. g(xi)=xi^{g_K} was found,
    2057              :  * then we fix an integer x_0 s.t. xi=x_0 (mod el) and construct x_i
    2058              :  * s.t. xi^{g_K^i}=x_i (mod el) using g(X). */
    2059              : static long
    2060            0 : chk_el_real_galois(GEN K, long p, long d_pow, long el, long j0)
    2061              : {
    2062            0 :   pari_sp av = avma;
    2063            0 :   GEN xi = gel(K, 7), T = gel(xi, 1), F = gel(xi, 2), Den = gel(xi, 3);
    2064              :   GEN Fel, xi_el, xi_e_chi, e_chi;
    2065            0 :   ulong i, j, x, found = 0;
    2066              :   ulong d_K, d, dp, el1dp;
    2067              : 
    2068            0 :   if (dvdiu(Den, el)) return 0;
    2069              : 
    2070            0 :   d = upowuu(p, d_pow); dp = d*p; el1dp = (el-1)/dp;
    2071            0 :   e_chi = get_e_chi(K, j0, dp, &d_K);
    2072            0 :   xi_el = cgetg(d_K+1, t_VECSMALL)+1;
    2073            0 :   xi_e_chi = cgetg(d_K+1, t_VECSMALL)+1;
    2074              : 
    2075            0 :   if (DEBUGLEVEL>1) err_printf("chk_el_real_galois: d_K=%ld el=%ld\n",d_K,el);
    2076            0 :   Fel = ZX_to_Flx(F, el);
    2077            0 :   Fel = Flx_Fl_mul(Fel, Fl_inv(umodiu(Den, el), el), el);
    2078            0 :   x = Flx_oneroot_split(ZX_to_Flx(T, el), el);
    2079            0 :   for (i=0; i<d_K; i++) { xi_el[i] = x; x = Flx_eval(Fel, x, el); }
    2080            0 :   if (DEBUGLEVEL>2) err_printf("el=%ld xi_el=%Ps\n", el, xi_el-1);
    2081            0 :   for (i=0; i<d_K; i++)
    2082              :   {
    2083            0 :     long z = 1;
    2084            0 :     for (j=0; j<d_K; j++)
    2085            0 :       z = Fl_mul(z, Fl_powu(xi_el[j], e_chi[(i+j)%d_K], el), el);
    2086            0 :     xi_e_chi[i] = z;
    2087              :   }
    2088            0 :   if (DEBUGLEVEL>2) err_printf("xi_e_chi=%Ps\n", xi_e_chi-1);
    2089            0 :   for (i=0; i<d_K; i++)
    2090              :   {
    2091            0 :     long x = Fl_powu(xi_e_chi[i], el1dp, el);
    2092            0 :     if (x!=1) found = 1;
    2093            0 :     if (Fl_powu(x, p, el)!=1) return gc_long(av, 0);
    2094              :   }
    2095            0 :   return gc_long(av, found);
    2096              : }
    2097              : 
    2098              : /* checks the condition of el using the irreducible polynomial G_K(X) of zeta_f
    2099              :  * over K. G_K(X) mod el is enough for our purpose and it is obtained by
    2100              :  * factoring polcyclo(f) mod el */
    2101              : static long
    2102            7 : chk_el_real_factor(GEN K, long p, long d_pow, long el, long j0)
    2103              : {
    2104            7 :   pari_sp av = avma;
    2105            7 :   GEN H = K_get_H(K);
    2106            7 :   ulong f = K_get_f(K), h = K_get_h(K), g_K = K_get_g(K);
    2107            7 :   ulong i, j, k, d_K, d = upowuu(p, d_pow), dp = d*p, found = 0;
    2108              :   GEN pols, coset, vn_g, polnum, xpows, G_K;
    2109            7 :   ulong el1dp = (el-1)/dp, n_coset, n_g, gi;
    2110            7 :   GEN e_chi = get_e_chi(K, j0, dp, &d_K);
    2111              :   pari_timer ti;
    2112              : 
    2113            7 :   if (DEBUGLEVEL>1) err_printf("chk_el_real_factor: f=%ld el=%ld\n",f,el);
    2114            7 :   coset = get_coset(H, h, f, el);
    2115            7 :   if (DEBUGLEVEL>1)
    2116              :   {
    2117            0 :     timer_start(&ti);
    2118            0 :     err_printf("factoring polyclo(d) (mod %ld)\n",f, el);
    2119              :   }
    2120            7 :   pols = Flx_factcyclo(f, el, 0);
    2121            7 :   if (DEBUGLEVEL>1) timer_printf(&ti,"Flx_factcyclo(%lu,%lu)",f,el);
    2122            7 :   n_coset = lg(coset)-1;
    2123            7 :   n_g = lg(pols)-1;
    2124            7 :   vn_g = identity_perm(n_g);
    2125              : 
    2126            7 :   polnum = const_vec(d_K, NULL);
    2127           91 :   for (i=1; i<=d_K; i++) gel(polnum, i) = const_vecsmall(n_coset, 0);
    2128            7 :   xpows = Flxq_powers(polx_Flx(0), f-1, gel(pols, 1), el);
    2129           91 :   for (gi=1,i=1; i<=d_K; i++)
    2130              :   {
    2131         3108 :     for (j=1; j<=n_coset; j++)
    2132              :     {
    2133         3024 :       long x, conj = Fl_mul(gi, coset[j], f);
    2134         3024 :       x = srh_pol(xpows, vn_g, pols, el, conj, f);
    2135         3024 :       gel(polnum, i)[j] = x;
    2136              :     }
    2137           84 :     gi = Fl_mul(gi, g_K, f);
    2138              :   }
    2139            7 :   G_K = const_vec(d_K, NULL);
    2140           91 :   for (i=1; i<=d_K; i++)
    2141              :   {
    2142           84 :     GEN z = pol1_Flx(0);
    2143         3108 :     for (j=1; j<=n_coset; j++) z = Flx_mul(z, gel(pols, gel(polnum,i)[j]), el);
    2144           84 :     gel(G_K, i) = z;
    2145              :   }
    2146            7 :   if (DEBUGLEVEL>2) err_printf("G_K(x)=%Ps\n",Flx_to_ZX(gel(G_K, 1)));
    2147           91 :   for (k=0; k<d_K; k++)
    2148              :   {
    2149           84 :     long x = 1;
    2150         1092 :     for (i = 0; i < d_K; i++)
    2151              :     {
    2152              :       long x0, t;
    2153         1008 :       x0 = Flx_eval(gel(G_K, 1+i), 1, el);
    2154         1008 :       t = Fl_powu(x0, e_chi[(i+k)%d_K], el);
    2155         1008 :       x = Fl_mul(x, t, el);
    2156              :     }
    2157           84 :     x = Fl_powu(x, el1dp, el);
    2158           84 :     if (x!=1) found = 1;
    2159           84 :     if (Fl_powu(x, p, el)!=1) return gc_long(av, 0);
    2160              :   }
    2161            7 :   return gc_long(av, found);
    2162              : }
    2163              : 
    2164              : static long
    2165           21 : chk_el_real_chi(GEN K, ulong p, ulong d_pow, ulong el, ulong j0, long flag)
    2166              : {
    2167           21 :   ulong f = K_get_f(K);
    2168              : 
    2169           21 :   if (el%f == 1)
    2170            0 :     return chk_el_real_f(K, p, d_pow, el, j0); /* must be faster */
    2171           21 :   if (flag&USE_BASIS)
    2172           14 :     return chk_el_real_basis(K, p, d_pow, el, j0);
    2173            7 :   if (flag&USE_GALOIS_POL)
    2174            0 :     return chk_el_real_galois(K, p, d_pow, el, j0);
    2175            7 :   return chk_el_real_factor(K, p, d_pow, el, j0);
    2176              : }
    2177              : 
    2178              : static long
    2179          616 : chk_ell_real(GEN K, long d2, GEN ell, long j0)
    2180              : {
    2181          616 :   pari_sp av = avma;
    2182          616 :   GEN H = K_get_H(K);
    2183          616 :   ulong f = K_get_f(K), h = K_get_h(K), g_K = K_get_g(K);
    2184              :   ulong d_K, i, j, gi;
    2185          616 :   GEN e_chi = get_e_chi(K, j0, d2, &d_K);
    2186          616 :   GEN g_ell, z_f, vz_f, xi_el = cgetg(d_K+1, t_VEC)+1;
    2187          616 :   GEN ell_1 = subiu(ell,1), ell1d2 = diviuexact(ell_1, d2);
    2188              : 
    2189          616 :   g_ell = pgener_Fp(ell);
    2190          616 :   z_f = Fp_pow(g_ell, diviuexact(subiu(ell, 1), f), ell);
    2191          616 :   vz_f = Fp_powers(z_f, f-1, ell)+1;
    2192        12964 :   for (gi=1, i=0; i<d_K; i++)
    2193              :   {
    2194        12348 :     GEN x = gen_1;
    2195      1074948 :     for (j = 1; j <= h; j++)
    2196              :     {
    2197      1062600 :       ulong y = Fl_mul(H[j], gi, f);
    2198      1062600 :       x = Fp_mul(x, subiu(gel(vz_f, y), 1), ell); /* vz_f[y] = z_f^y  */
    2199              :     }
    2200        12348 :     gi = Fl_mul(gi, g_K, f);
    2201        12348 :     gel(xi_el, i) = x;  /* xi_el[i]=xi^{g_K^i} */
    2202              :   }
    2203         1421 :   for (i=0; i<d_K; i++)
    2204              :   {
    2205         1386 :     GEN x = gen_1;
    2206        31976 :     for (j=0; j<d_K; j++)
    2207        30590 :       x = Fp_mul(x, Fp_powu(gel(xi_el, j), e_chi[(i+j)%d_K], ell), ell);
    2208         1386 :     x = Fp_pow(x, ell1d2, ell);
    2209         1386 :     if (!equali1(x)) return gc_long(av, 0);
    2210              :   }
    2211           35 :   return gc_long(av, 1);
    2212              : }
    2213              : 
    2214              : static GEN
    2215           21 : next_el_real(GEN K, long p, long d_pow, GEN elg, long j0, long flag)
    2216              : {
    2217           21 :   GEN Chi = gel(K, 2);
    2218           21 :   ulong f = K_get_f(K), h = K_get_h(K), d = upowuu(p, d_pow), d2 = d*d;
    2219           21 :   ulong D = (flag & USE_F)? d2*f: d2<<1, el = elg[1] + D;
    2220              : 
    2221              :   /* O(el*h) -> O(el*log(el)) by FFT */
    2222           21 :   if (1000 < h && el < h) { el = (h/D)*D+1; if (el < h) el += D; }
    2223           21 :   if (flag&USE_F)  /* el=1 (mod f) */
    2224              :   {
    2225            0 :     for (;; el += D)
    2226            0 :       if (uisprime(el) && chk_el_real_f(K, p, d_pow, el, j0)) break;
    2227              :   }
    2228              :   else
    2229              :   {
    2230          413 :     for (;; el += D)
    2231          455 :       if (Chi[el%f]==0 && uisprime(el) &&
    2232           42 :           chk_el_real_chi(K, p, d_pow, el, j0, flag)) break;
    2233              :   }
    2234           21 :   return mkvecsmall2(el, pgener_Fl(el));
    2235              : }
    2236              : 
    2237              : static GEN
    2238           35 : next_ell_real(GEN K, GEN ellg, long d2, GEN df0l, long j0)
    2239              : {
    2240           35 :   GEN ell = gel(ellg, 1);
    2241         7602 :   for (ell = addii(ell, df0l);; ell = addii(ell, df0l))
    2242         7602 :     if (BPSW_psp(ell) && chk_ell_real(K, d2, ell, j0))
    2243           35 :       return mkvec2(ell, pgener_Fp(ell));
    2244              : }
    2245              : 
    2246              : /* #velg >= n */
    2247              : static long
    2248            0 : delete_el(GEN velg, long n)
    2249              : {
    2250              :   long i, l;
    2251            0 :   if (DEBUGLEVEL>1) err_printf("deleting %ld ...\n", gmael(velg, n, 1));
    2252            0 :   for (l = lg(velg)-1; l >= 1; l--) if (gel(velg, l)) break;
    2253            0 :   for (i = n; i < l; i++) gel(velg, i) = gel(velg, i+1);
    2254            0 :   return l;
    2255              : }
    2256              : 
    2257              : /* velg has n components */
    2258              : static GEN
    2259           21 : set_ell_real(GEN K, GEN velg, long n, long d_chi, long d2, long f0, long j0)
    2260              : {
    2261           21 :   long i, n_ell = n*d_chi;
    2262           21 :   GEN z = cgetg(n_ell + 1, t_VEC);
    2263           21 :   GEN df0l = muluu(d2, f0), ellg = mkvec2(gen_1, gen_1);
    2264           42 :   for (i=1; i<=n; i++) df0l = muliu(df0l, gel(velg, i)[1]);
    2265           56 :   for (i=1; i<=n_ell; i++) ellg = gel(z, i)= next_ell_real(K, ellg, d2, df0l, j0);
    2266           21 :   return z;
    2267              : }
    2268              : 
    2269              : static GEN
    2270          182 : G_K_vell(GEN K, GEN vellg, ulong gk)
    2271              : {
    2272          182 :   pari_sp av = avma;
    2273          182 :   GEN H = K_get_H(K);
    2274          182 :   ulong f = K_get_f(K), h = K_get_h(K);
    2275          182 :   GEN z_f, vz_f, A, P, M, z =  cgetg(h+1, t_VEC);
    2276          182 :   ulong i, lv = lg(vellg);
    2277              : 
    2278          182 :   A=cgetg(lv, t_VEC);
    2279          182 :   P=cgetg(lv, t_VEC);
    2280          728 :   for (i=1; i<lv; i++)
    2281              :   {
    2282          546 :     GEN ell = gmael(vellg, i, 1), g_ell = gmael(vellg, i, 2);
    2283          546 :     gel(A, i) = Fp_pow(g_ell, diviuexact(subiu(ell, 1), f), ell);
    2284          546 :     gel(P, i) = ell;
    2285              :   }
    2286          182 :   z_f = ZV_chinese(A, P, &M);
    2287          182 :   vz_f = Fp_powers(z_f, f-1, M)+1;
    2288         3822 :   for (i=1; i<=h; i++) gel(z, i) = gel(vz_f, Fl_mul(H[i], gk, f));
    2289          182 :   return gc_GEN(av, FpV_roots_to_pol(z, M, 0));
    2290              : }
    2291              : 
    2292              : /* f=cond(K), M=product of ell in vell, G(K/Q)=<g_K>
    2293              :  * G_K[1+i]=minimal polynomial of zeta_f^{g_k^i} over K mod M, 0 <= i < d_K */
    2294              : static GEN
    2295            7 : make_G_K(GEN K, GEN vellg)
    2296              : {
    2297            7 :   ulong d_K = K_get_d(K), f = K_get_f(K), g_K = K_get_g(K);
    2298            7 :   GEN G_K = cgetg(d_K+1, t_VEC);
    2299            7 :   ulong i, g = 1;
    2300              : 
    2301          189 :   for (i=0; i<d_K; i++)
    2302              :   {
    2303          182 :     gel(G_K, 1+i) = G_K_vell(K, vellg, g);
    2304          182 :     g = Fl_mul(g, g_K, f);
    2305              :   }
    2306            7 :   return G_K;
    2307              : }
    2308              : 
    2309              : static GEN
    2310           12 : G_K_p(GEN K, GEN ellg, ulong gk)
    2311              : {
    2312           12 :   pari_sp av = avma;
    2313           12 :   ulong i, f = K_get_f(K), h = K_get_h(K);
    2314           12 :   GEN ell = gel(ellg, 1), g_ell = gel(ellg, 2);
    2315           12 :   GEN H = K_get_H(K), z_f, vz_f, z = cgetg(h+1, t_VEC);
    2316              : 
    2317           12 :   z_f = Fp_pow(g_ell, diviuexact(subiu(ell, 1), f), ell);
    2318           12 :   vz_f = Fp_powers(z_f, f-1, ell)+1;
    2319         3468 :   for (i=1; i<=h; i++) gel(z, i) = gel(vz_f, Fl_mul(H[i], gk, f));
    2320           12 :   return gc_GEN(av, FpV_roots_to_pol(z, ell, 0));
    2321              : }
    2322              : 
    2323              : static GEN
    2324          114 : G_K_l(GEN K, GEN ellg, ulong gk)
    2325              : {
    2326          114 :   pari_sp av = avma;
    2327          114 :   ulong ell = itou(gel(ellg, 1)), g_ell = itou(gel(ellg, 2));
    2328          114 :   ulong f = K_get_f(K), h = K_get_h(K), i, z_f;
    2329          114 :   GEN H = K_get_H(K), vz_f, z = cgetg(h+1, t_VEC);
    2330              : 
    2331          114 :   z_f = Fl_powu(g_ell, (ell-1) / f, ell);
    2332          114 :   vz_f = Fl_powers(z_f, f-1, ell)+1;
    2333        26898 :   for (i=1; i<=h; i++) z[i] = vz_f[Fl_mul(H[i], gk, f)];
    2334          114 :   return gc_GEN(av, Flv_roots_to_pol(z, ell, 0));
    2335              : }
    2336              : 
    2337              : static GEN
    2338            6 : vz_vell(long d, GEN vellg, GEN *pM)
    2339              : {
    2340            6 :   long i, l = lg(vellg);
    2341            6 :   GEN A = cgetg(l, t_VEC), P = cgetg(l, t_VEC), z;
    2342              : 
    2343           18 :   for (i = 1; i < l; i++)
    2344              :   {
    2345           12 :     GEN ell = gmael(vellg, i, 1), g_ell = gmael(vellg, i, 2);
    2346           12 :     gel(A, i) = Fp_pow(g_ell, diviuexact(subiu(ell, 1), d), ell);
    2347           12 :     gel(P, i) = ell;
    2348              :   }
    2349            6 :   z = ZV_chinese(A, P, pM); return Fp_powers(z, d-1, *pM);
    2350              : }
    2351              : 
    2352              : static GEN
    2353            0 : D_xi_el_vell_FFT(GEN K, GEN elg, GEN vellg, ulong d, ulong j0, GEN vG_K)
    2354              : {
    2355            0 :   pari_sp av = avma;
    2356            0 :   ulong d_K, h = K_get_h(K), d_chi = K_get_dchi(K);
    2357            0 :   ulong el = elg[1], g_el = elg[2], el_1 = el-1;
    2358              :   ulong i, j, i2, k, dwel;
    2359            0 :   GEN u = cgetg(el+2, t_POL), v = cgetg(h+3, t_POL);
    2360            0 :   GEN w = cgetg(el+1, t_VEC), ww;
    2361            0 :   GEN M, vz_el, G_K, z = const_vec(d_chi, gen_1);
    2362            0 :   GEN e_chi = get_e_chi(K, j0, d, &d_K);
    2363              : 
    2364            0 :   vz_el = vz_vell(el, vellg, &M);
    2365            0 :   u[1] = evalsigne(1) | evalvarn(0);
    2366            0 :   v[1] = evalsigne(1) | evalvarn(0);
    2367              : 
    2368            0 :   for (i=i2=0; i<el; i++)
    2369              :   {
    2370            0 :     ulong j2 = i2?el-i2:i2; /* i2=(i*i)%el */
    2371            0 :     gel(u, 2+i) = gel(vz_el, 1+j2);
    2372            0 :     if ((i2+=i+i+1)>=el) i2%=el;
    2373              :   }
    2374            0 :   for (k=0; k<d_K; k++)
    2375              :   {
    2376            0 :     pari_sp av = avma;
    2377              :     pari_timer ti;
    2378              :     long gd, gi;
    2379            0 :     GEN x1 = gen_1;
    2380            0 :     G_K = gel(vG_K, 1+k);
    2381            0 :     for (i=i2=0; i<=h; i++)
    2382              :     {
    2383            0 :       gel(v, 2+i) = Fp_mul(gel(G_K, 2+i), gel(vz_el, 1+i2), M);
    2384            0 :       if ((i2+=i+i+1)>=el) i2%=el;
    2385              :     }
    2386            0 :     if (DEBUGLEVEL>2) timer_start(&ti);
    2387            0 :     ww = ZX_mul(u, v);
    2388            0 :     if (DEBUGLEVEL>2)
    2389            0 :       timer_printf(&ti, "ZX_mul:%ld/%ld h*el=%ld*%ld", k, d_K, h, el);
    2390            0 :     dwel = degpol(ww)-el;
    2391            0 :     for (i=0; i<=dwel; i++) gel(w, 1+i) = addii(gel(ww, 2+i), gel(ww, 2+i+el));
    2392            0 :     for (; i<el; i++) gel(w, 1+i) = gel(ww, 2+i);
    2393            0 :     for (i=i2=1; i<el; i++)  /* w[i]=G_K(z_el^(2*i)) */
    2394              :     {
    2395            0 :       gel(w, i) = Fp_mul(gel(w, 1+i), gel(vz_el, 1+i2), M);
    2396            0 :       if ((i2+=i+i+1)>=el) i2%=el;
    2397              :     }
    2398            0 :     gd = Fl_powu(g_el, d, el);  /* a bit faster */
    2399            0 :     gi = g_el;
    2400            0 :     for (i=1; i<d; i++)
    2401              :     {
    2402            0 :       GEN xi = gen_1;
    2403            0 :       long gdi = gi;
    2404            0 :       for (j=0; i+j<el_1; j+=d)
    2405              :       {
    2406            0 :         xi = Fp_mul(xi, gel(w, (gdi+gdi)%el), M);
    2407            0 :         gdi = Fl_mul(gdi, gd, el);
    2408              :       }
    2409            0 :       gi = Fl_mul(gi, g_el, el);
    2410            0 :       xi = Fp_powu(xi, i, M);
    2411            0 :       x1 = Fp_mul(x1, xi, M);
    2412              :     }
    2413            0 :     for (i=1; i<=d_chi; i++)
    2414              :     {
    2415            0 :       GEN x2 = Fp_powu(x1, e_chi[(k+i-1)%d_K], M);
    2416            0 :       gel(z, i) = Fp_mul(gel(z, i), x2, M);
    2417              :     }
    2418            0 :     z = gc_GEN(av, z);
    2419              :   }
    2420            0 :   return gc_GEN(av, z);
    2421              : }
    2422              : 
    2423              : static GEN
    2424            0 : D_xi_el_vell(GEN K, GEN elg, GEN vellg, ulong d, ulong j0)
    2425              : {
    2426            0 :   pari_sp av = avma;
    2427            0 :   GEN H = K_get_H(K);
    2428            0 :   ulong f = K_get_f(K), h = K_get_h(K), g_K = K_get_g(K);
    2429              :   GEN z_f, z_el, vz_f, vz_el;
    2430            0 :   ulong el = elg[1], g_el = elg[2], el_1 = el-1;
    2431            0 :   ulong i, j, k, d_K, lv = lg(vellg), d_chi = K_get_dchi(K);
    2432            0 :   GEN A, B, P, M, z = const_vec(d_chi, gen_1);
    2433            0 :   GEN e_chi = get_e_chi(K, j0, d, &d_K);
    2434              : 
    2435            0 :   A=cgetg(lv, t_VEC);
    2436            0 :   B=cgetg(lv, t_VEC);
    2437            0 :   P=cgetg(lv, t_VEC);
    2438            0 :   for (i = 1; i < lv; i++)
    2439              :   {
    2440            0 :     GEN ell = gmael(vellg, i, 1), g_ell = gmael(vellg, i, 2);
    2441            0 :     GEN ell_1 = subiu(ell, 1);
    2442            0 :     gel(A, i) = Fp_pow(g_ell, diviuexact(ell_1, f), ell);
    2443            0 :     gel(B, i) = Fp_pow(g_ell, diviuexact(ell_1, el), ell);
    2444            0 :     gel(P, i) = ell;
    2445              :   }
    2446            0 :   z_f = ZV_chinese(A, P, &M);
    2447            0 :   z_el = ZV_chinese(B, P, NULL);
    2448            0 :   vz_f = Fp_powers(z_f, f-1, M);
    2449            0 :   vz_el = Fp_powers(z_el, el-1, M);
    2450            0 :   for (k = 0; k < d_K; k++)
    2451              :   {
    2452            0 :     pari_sp av = avma;
    2453            0 :     GEN x0 = gen_1;
    2454            0 :     long gk = Fl_powu(g_K, k, f);
    2455            0 :     for (i=1; i<el_1; i++)
    2456              :     {
    2457            0 :       long gi = Fl_powu(g_el, i, el);
    2458            0 :       GEN x1 = gen_1;
    2459            0 :       GEN x2 = gel(vz_el, 1+gi);
    2460            0 :       for (j=1; j<=h; j++)
    2461              :       {
    2462            0 :         long y = Fl_mul(H[j], gk, f);
    2463            0 :         x1 = Fp_mul(x1, Fp_sub(x2, gel(vz_f, 1+y), M), M);
    2464              :       }
    2465            0 :       x1 = Fp_powu(x1, i%d, M);
    2466            0 :       x0 = Fp_mul(x0, x1, M);
    2467              :     }
    2468            0 :     for (i=1; i<=d_chi; i++)
    2469              :     {
    2470            0 :       GEN x2 = Fp_powu(x0, e_chi[(k+i-1)%d_K], M);
    2471            0 :       gel(z, i) = Fp_mul(gel(z, i), x2, M);
    2472              :     }
    2473            0 :     z = gc_GEN(av, z);
    2474              :   }
    2475            0 :   return gc_GEN(av, z);
    2476              : }
    2477              : 
    2478              : static GEN
    2479           34 : D_xi_el_Flx_mul(GEN K, GEN elg, GEN ellg, GEN vG_K, ulong d, ulong j0)
    2480              : {
    2481           34 :   pari_sp av = avma;
    2482           34 :   ulong d_K, f = K_get_f(K), h = K_get_h(K), g_K = K_get_g(K);
    2483           34 :   ulong el = elg[1], g_el = elg[2], el_1 = el-1, d_chi = K_get_dchi(K);
    2484           34 :   ulong ell = itou(gel(ellg, 1)), g_ell = itou(gel(ellg, 2)), z_el;
    2485           34 :   GEN u = cgetg(el+2, t_VECSMALL), v = cgetg(h+3, t_VECSMALL);
    2486           34 :   GEN w = cgetg(el+1, t_VECSMALL), ww;
    2487           34 :   GEN vz_el, G_K, z = const_vecsmall(d_chi, 1);
    2488           34 :   GEN e_chi = get_e_chi(K, j0, d, &d_K);
    2489              :   ulong i, j, i2, k, dwel;
    2490              : 
    2491           34 :   u[1] = evalvarn(0);
    2492           34 :   v[1] = evalvarn(0);
    2493           34 :   z_el = Fl_powu(g_ell, (ell - 1) / el, ell);
    2494           34 :   vz_el = Fl_powers(z_el, el_1, ell)+1;
    2495              : 
    2496       700376 :   for (i=i2=0; i<el; i++)
    2497              :   {
    2498       700342 :     ulong j2 = i2?el-i2:i2;
    2499       700342 :     u[2+i] = vz_el[j2];
    2500       700342 :     if ((i2+=i+i+1)>=el) i2%=el;  /* i2=(i*i)%el */
    2501              :   }
    2502          694 :   for (k=0; k<d_K; k++)
    2503              :   {
    2504          660 :     pari_sp av = avma;
    2505              :     pari_timer ti;
    2506          660 :     ulong gk = Fl_powu(g_K, k, f);
    2507          660 :     long gd, gi, x1 = 1;
    2508          660 :     if (DEBUGLEVEL>2) timer_start(&ti);
    2509          660 :     G_K = (vG_K==NULL)?G_K_l(K, ellg, gk):ZX_to_Flx(gel(vG_K, 1+k), ell);
    2510          660 :     if (DEBUGLEVEL>2) timer_printf(&ti, "G_K_l");
    2511        39024 :     for (i=i2=0; i<=h; i++)
    2512              :     {
    2513        38364 :       v[2+i] = Fl_mul(G_K[2+i], vz_el[i2], ell);
    2514        38364 :       if ((i2+=i+i+1)>=el) i2%=el;  /* i2=(i*i)%el */
    2515              :     }
    2516          660 :     if (DEBUGLEVEL>2) timer_start(&ti);
    2517          660 :     ww = Flx_mul(u, v, ell);
    2518          660 :     if (DEBUGLEVEL>2)
    2519            0 :       timer_printf(&ti, "Flx_mul:%ld/%ld h*el=%ld*%ld", k, d_K, h, el);
    2520          660 :     dwel=degpol(ww)-el; /* dwel=h-1 */
    2521        38364 :     for (i=0; i<=dwel; i++) w[1+i] = Fl_add(ww[2+i], ww[2+i+el], ell);
    2522      8388480 :     for (; i<el; i++) w[1+i] = ww[2+i];
    2523      8425524 :     for (i=i2=1; i<el; i++)  /* w[i]=G_K(z_el^(2*i)) */
    2524              :     {
    2525      8424864 :       w[i] = Fl_mul(w[1+i], vz_el[i2], ell);
    2526      8424864 :       if ((i2+=i+i+1)>=el) i2%=el;  /* i2=(i*i)%el */
    2527              :     }
    2528          660 :     gd = Fl_powu(g_el, d, el);  /* a bit faster */
    2529          660 :     gi = g_el;
    2530         4596 :     for (i=1; i<d; i++)
    2531              :     {
    2532         3936 :       long xi = 1, gdi = gi;
    2533      8163696 :       for (j=0; i+j<el_1; j+=d)
    2534              :       {
    2535      8159760 :         xi = Fl_mul(xi, w[(gdi+gdi)%el], ell);
    2536      8159760 :         gdi = Fl_mul(gdi, gd, el);
    2537              :       }
    2538         3936 :       gi = Fl_mul(gi, g_el, el);
    2539         3936 :       xi = Fl_powu(xi, i, ell);
    2540         3936 :       x1 = Fl_mul(x1, xi, ell);
    2541              :     }
    2542         2412 :     for (i=1; i<=d_chi; i++)
    2543              :     {
    2544         1752 :       long x2 = Fl_powu(x1, e_chi[(k+i-1)%d_K], ell);
    2545         1752 :       z[i] = Fl_mul(z[i], x2, ell);
    2546              :     }
    2547          660 :     set_avma(av);
    2548              :   }
    2549           34 :   return gc_GEN(av, Flv_to_ZV(z));
    2550              : }
    2551              : 
    2552              : static GEN
    2553           35 : D_xi_el_ZX_mul(GEN K, GEN elg, GEN ellg, GEN vG_K, ulong d, ulong j0)
    2554              : {
    2555           35 :   pari_sp av = avma;
    2556           35 :   GEN ell = gel(ellg,1), g_ell, u, v, w, ww, z_el, vz_el, G_K, z, e_chi;
    2557              :   ulong d_K, f, h, g_K, el, g_el, el_1, d_chi, i, j, i2, k, dwel;
    2558              : 
    2559           35 :   if (lgefint(ell) == 3) return D_xi_el_Flx_mul(K, elg, ellg, vG_K, d, j0);
    2560            1 :   f = K_get_f(K); h = K_get_h(K); g_K = K_get_g(K);
    2561            1 :   el = elg[1]; g_el = elg[2]; el_1 = el-1; d_chi = K_get_dchi(K);
    2562            1 :   g_ell = gel(ellg, 2);
    2563            1 :   z = const_vec(d_chi, gen_1);
    2564            1 :   e_chi = get_e_chi(K, j0, d, &d_K);
    2565              : 
    2566            1 :   u = cgetg(el+2,t_POL); u[1] = evalsigne(1) | evalvarn(0);
    2567            1 :   v = cgetg(h+3, t_POL); v[1] = evalsigne(1) | evalvarn(0);
    2568            1 :   w = cgetg(el+1, t_VEC);
    2569            1 :   z_el = Fp_pow(g_ell, diviuexact(subiu(ell, 1), el), ell);
    2570            1 :   vz_el = Fp_powers(z_el, el_1, ell)+1;
    2571              : 
    2572       114998 :   for (i=i2=0; i<el; i++)
    2573              :   {
    2574       114997 :     ulong j2 = i2?el-i2:i2; /* i2=(i*i)%el */
    2575       114997 :     gel(u, 2+i) = gel(vz_el, j2);
    2576       114997 :     if ((i2+=i+i+1)>=el) i2%=el;
    2577              :   }
    2578           13 :   for (k=0; k<d_K; k++)
    2579              :   {
    2580           12 :     pari_sp av = avma;
    2581              :     pari_timer ti;
    2582           12 :     long gd, gi, gk = Fl_powu(g_K, k, f);
    2583           12 :     GEN x1 = gen_1;
    2584           12 :     if (DEBUGLEVEL>2) timer_start(&ti);
    2585           12 :     G_K = (vG_K==NULL) ? G_K_p(K, ellg, gk):RgX_to_FpX(gel(vG_K, 1+k), ell);
    2586           12 :     if (DEBUGLEVEL>2) timer_printf(&ti, "G_K_p");
    2587         3480 :     for (i=i2=0; i<=h; i++)
    2588              :     {
    2589         3468 :       gel(v, 2+i) = Fp_mul(gel(G_K, 2+i), gel(vz_el, i2), ell);
    2590         3468 :       if ((i2+=i+i+1)>=el) i2%=el;
    2591              :     }
    2592           12 :     if (DEBUGLEVEL>2) timer_start(&ti);
    2593           12 :     ww = ZX_mul(u, v);
    2594           12 :     if (DEBUGLEVEL>2)
    2595            0 :       timer_printf(&ti, "ZX_mul:%ld/%ld h*el=%ld*%ld", k, d_K, h, el);
    2596           12 :     dwel = degpol(ww)-el;
    2597         3468 :     for (i=0; i<=dwel; i++) gel(w, 1+i) = addii(gel(ww, 2+i), gel(ww, 2+i+el));
    2598      1376520 :     for (; i<el; i++) gel(w, 1+i) = gel(ww, 2+i);
    2599      1379964 :     for (i=i2=1; i<el; i++)  /* w[i]=G_K(z_el^(2*i)) */
    2600              :     {
    2601      1379952 :       gel(w, i) = Fp_mul(gel(w, 1+i), gel(vz_el, i2), ell);
    2602      1379952 :       if ((i2+=i+i+1)>=el) i2%=el;
    2603              :     }
    2604           12 :     gd = Fl_powu(g_el, d, el);  /* a bit faster */
    2605           12 :     gi = g_el;
    2606          444 :     for (i=1; i<d; i++)
    2607              :     {
    2608          432 :       GEN xi = gen_1;
    2609          432 :       long gdi = gi;
    2610      1343088 :       for (j=0; i+j<el_1; j+=d)
    2611              :       {
    2612      1342656 :         xi = Fp_mul(xi, gel(w, (gdi+gdi)%el), ell);
    2613      1342656 :         gdi = Fl_mul(gdi, gd, el);
    2614              :       }
    2615          432 :       gi = Fl_mul(gi, g_el, el);
    2616          432 :       xi = Fp_powu(xi, i, ell);
    2617          432 :       x1 = Fp_mul(x1, xi, ell);
    2618              :     }
    2619           24 :     for (i=1; i<=d_chi; i++)
    2620              :     {
    2621           12 :       GEN x2 = Fp_powu(x1, e_chi[(k+i-1)%d_K], ell);
    2622           12 :       gel(z, i) = Fp_mul(gel(z, i), x2, ell);
    2623              :     }
    2624           12 :     z = gc_GEN(av, z);
    2625              :   }
    2626            1 :   return gc_GEN(av, z);
    2627              : }
    2628              : 
    2629              : static GEN
    2630            0 : D_xi_el_ss(GEN K, GEN elg, GEN ellg, ulong d, ulong j0)
    2631              : {
    2632            0 :   pari_sp av = avma;
    2633            0 :   GEN H = K_get_H(K);
    2634            0 :   ulong d_K, f = K_get_f(K), h = K_get_h(K), g_K = K_get_g(K);
    2635            0 :   ulong el = elg[1], g_el = elg[2], el_1 = el-1;
    2636            0 :   ulong ell = itou(gel(ellg, 1)), g_ell = itou(gel(ellg, 2));
    2637            0 :   ulong i, j, k, gk, z_f, z_el, d_chi = K_get_dchi(K);
    2638            0 :   GEN vz_f, vz_el, z = const_vecsmall(d_chi, 1);
    2639            0 :   GEN e_chi = get_e_chi(K, j0, d, &d_K);
    2640              : 
    2641            0 :   z_f = Fl_powu(g_ell, (ell - 1) / f, ell);
    2642            0 :   z_el = Fl_powu(g_ell, (ell - 1) / el, ell);
    2643            0 :   vz_f = Fl_powers(z_f, f-1, ell)+1;
    2644            0 :   vz_el = Fl_powers(z_el, el-1, ell)+1;
    2645            0 :   gk = 1; /* g_K^k */
    2646            0 :   for (k = 0; k < d_K; k++)
    2647              :   {
    2648            0 :     ulong x0 = 1, gi = g_el; /* g_el^i */
    2649            0 :     for (i = 1; i < el_1; i++)
    2650              :     {
    2651            0 :       ulong x1 = 1, x2 = vz_el[gi];
    2652            0 :       for (j=1; j<=h; j++)
    2653              :       {
    2654            0 :         ulong y = Fl_mul(H[j], gk, f);
    2655            0 :         x1 = Fl_mul(x1, Fl_sub(x2, vz_f[y], ell), ell);
    2656              :       }
    2657            0 :       x1 = Fl_powu(x1, i%d, ell);
    2658            0 :       x0 = Fl_mul(x0, x1, ell);
    2659            0 :       gi = Fl_mul(gi, g_el, el);
    2660              :     }
    2661            0 :     for (i = 1; i <= d_chi; i++)
    2662              :     {
    2663            0 :       ulong x2 = Fl_powu(x0, e_chi[(k+i-1)%d_K], ell);
    2664            0 :       z[i] = Fl_mul(z[i], x2, ell);
    2665              :     }
    2666            0 :     gk = Fl_mul(gk, g_K, f);
    2667              :   }
    2668            0 :   return gc_upto(av, Flv_to_ZV(z));
    2669              : }
    2670              : 
    2671              : static GEN
    2672            0 : D_xi_el_sl(GEN K, GEN elg, GEN ellg, ulong d, ulong j0)
    2673              : {
    2674            0 :   pari_sp av = avma;
    2675            0 :   GEN ell = gel(ellg, 1), H;
    2676              :   GEN g_ell, ell_1, z_f, z_el, vz_f, vz_el, z, e_chi;
    2677              :   ulong d_K, f, h, g_K, el, g_el, el_1, d_chi, i, j, k, gk;
    2678              : 
    2679            0 :   if (lgefint(ell) == 3) return D_xi_el_ss(K, elg, ellg, d, j0);
    2680            0 :   H = K_get_H(K);
    2681            0 :   f = K_get_f(K); h = K_get_h(K); g_K = K_get_g(K);
    2682            0 :   el = elg[1]; g_el = elg[2]; el_1 = el-1; d_chi = K_get_dchi(K);
    2683            0 :   g_ell = gel(ellg, 2); ell_1 = subiu(ell, 1);
    2684            0 :   z = const_vec(d_chi, gen_1);
    2685            0 :   e_chi = get_e_chi(K, j0, d, &d_K);
    2686              : 
    2687            0 :   z_f = Fp_pow(g_ell, diviuexact(ell_1, f), ell);
    2688            0 :   z_el = Fp_pow(g_ell, diviuexact(ell_1, el), ell);
    2689            0 :   vz_f = Fp_powers(z_f, f-1, ell) + 1;
    2690            0 :   vz_el = Fp_powers(z_el, el-1, ell) + 1;
    2691            0 :   gk = 1; /* g_K^k */
    2692            0 :   for (k = 0; k < d_K; k++)
    2693              :   {
    2694            0 :     pari_sp av2 = avma;
    2695            0 :     GEN x0 = gen_1;
    2696            0 :     ulong gi = g_el; /* g_el^i */
    2697            0 :     for (i = 1; i < el_1; i++)
    2698              :     {
    2699            0 :       pari_sp av3 = avma;
    2700            0 :       GEN x1 = gen_1, x2 = gel(vz_el, gi);
    2701            0 :       for (j = 1; j <= h; j++)
    2702              :       {
    2703            0 :         ulong y = Fl_neg(Fl_mul(H[j], gk, f), f);
    2704            0 :         x1 = Fp_mul(x1, Fp_sub(x2, gel(vz_f, y), ell), ell);
    2705              :       }
    2706            0 :       x1 = Fp_powu(x1, i%d, ell);
    2707            0 :       x0 = gc_INT(av3, Fp_mul(x0, x1, ell));
    2708            0 :       gi = Fl_mul(gi, g_el, el);
    2709              :     }
    2710            0 :     for (i=1; i<=d_chi; i++)
    2711              :     {
    2712            0 :       GEN x2 = Fp_powu(x0, e_chi[(k+i-1)%d_K], ell);
    2713            0 :       gel(z, i) = Fp_mul(gel(z, i), x2, ell);
    2714              :     }
    2715            0 :     if (k == d_K-1) break;
    2716            0 :     z = gc_GEN(av2, z);
    2717            0 :     gk = Fl_mul(gk, g_K, f);
    2718              :   }
    2719            0 :   return gc_GEN(av, z);
    2720              : }
    2721              : 
    2722              : static long
    2723          175 : get_y(GEN z, GEN ellg, long d)
    2724              : {
    2725          175 :   GEN ell = gel(ellg, 1), g_ell = gel(ellg, 2);
    2726          175 :   GEN elld = diviuexact(subiu(ell, 1), d);
    2727          175 :   GEN g_elld = Fp_pow(g_ell, elld, ell);
    2728          175 :   GEN x = Fp_pow(modii(z, ell), elld, ell);
    2729              :   long k;
    2730       211778 :   for (k=0; k<d; k++)
    2731              :   {
    2732       211778 :     if (equali1(x)) break;
    2733       211603 :     x = Fp_mul(x, g_elld, ell);
    2734              :   }
    2735          175 :   if (k==0) k=d;
    2736          161 :   else if (d<=k) pari_err_BUG("subcyclopclgp [MLL]");
    2737          175 :   return k;
    2738              : }
    2739              : 
    2740              : static void
    2741            0 : real_MLLn(long *y, GEN K, ulong p, ulong d_pow, ulong n,
    2742              :     GEN velg, GEN vellg, GEN vG_K, ulong j0)
    2743              : {
    2744            0 :   pari_sp av = avma;
    2745            0 :   ulong i, j, k, d = upowuu(p, d_pow), h = gmael(K, 1, 2)[3];
    2746            0 :   ulong row = lg(vellg)-1;
    2747            0 :   for (i=1; i<=n; i++)
    2748              :   {
    2749            0 :     GEN elg = gel(velg, i), z;
    2750            0 :     ulong el = elg[1], nz;
    2751              :     pari_timer ti;
    2752            0 :     if (DEBUGLEVEL>1) timer_start(&ti);
    2753            0 :     z = (h<el) ? D_xi_el_vell_FFT(K, elg, vellg, d, j0, vG_K)
    2754            0 :                : D_xi_el_vell(K, elg, vellg, d, j0);
    2755            0 :     if (DEBUGLEVEL>1) timer_printf(&ti, "subcyclopclgp:[D_xi_el]");
    2756            0 :     if (DEBUGLEVEL>2) err_printf("z=%Ps\n", z);
    2757            0 :     nz = lg(z)-1;
    2758            0 :     for (k = 1; k <= nz; k++)
    2759            0 :       for (j=1; j<=row; j++)
    2760            0 :         y[(j-1)*row+(i-1)*nz+k-1] = get_y(gel(z, k), gel(vellg, j), d);
    2761            0 :     set_avma(av);
    2762              :   }
    2763            0 : }
    2764              : 
    2765              : static void
    2766           14 : real_MLL1(long *y, GEN K, ulong p, ulong d_pow, GEN velg, GEN vellg, ulong j0)
    2767              : {
    2768           14 :   ulong h = gmael(K, 1, 2)[3], d = upowuu(p, d_pow);
    2769           14 :   GEN elg = gel(velg, 1), ellg = gel(vellg, 1), z;
    2770           14 :   ulong el = elg[1];
    2771              :   pari_timer ti;
    2772              : 
    2773           14 :   if (DEBUGLEVEL>2) timer_start(&ti);
    2774           14 :   z = h < el? D_xi_el_ZX_mul(K, elg, ellg, NULL, d, j0)
    2775           14 :             : D_xi_el_sl(K, elg, ellg, d, j0);
    2776           14 :   if (DEBUGLEVEL>2) timer_printf(&ti, "subcyclopclgp:[D_xi_el]");
    2777           14 :   if (DEBUGLEVEL>2) err_printf("z=%Ps\n", z);
    2778           14 :   y[0] = get_y(gel(z, 1), ellg, d);
    2779           14 : }
    2780              : 
    2781              : static void
    2782            7 : real_MLL(long *y, GEN K, ulong p, ulong d_pow, ulong n,
    2783              :     GEN velg, GEN vellg, GEN vG_K, ulong j0)
    2784              : {
    2785            7 :   ulong i, j, k, d = upowuu(p, d_pow), h = gmael(K, 1, 2)[3];
    2786            7 :   ulong row = lg(vellg)-1;
    2787           28 :   for (j=1; j<=row; j++)
    2788              :   {
    2789           21 :     GEN ellg = gel(vellg, j);
    2790           42 :     for (i=1; i<=n; i++)
    2791              :     {
    2792           21 :       pari_sp av2 = avma;
    2793           21 :       GEN elg = gel(velg, i), z;
    2794           21 :       ulong el = elg[1], nz;
    2795              :       pari_timer ti;
    2796           21 :       if (DEBUGLEVEL>2) timer_start(&ti);
    2797           21 :       z = h < el? D_xi_el_ZX_mul(K, elg, ellg, vG_K, d, j0)
    2798           21 :                 : D_xi_el_sl(K, elg, ellg, d, j0);
    2799           21 :       if (DEBUGLEVEL>2) timer_printf(&ti, "subcyclopclgp:[D_xi_el]");
    2800           21 :       if (DEBUGLEVEL>3) err_printf("z=%Ps\n", z);
    2801           21 :       nz = lg(z)-1;
    2802           84 :       for (k = 1; k <= nz; k++)
    2803           63 :         y[(j-1)*row+(i-1)*nz+k-1] = get_y(gel(z, k), ellg, d);
    2804           21 :       set_avma(av2);
    2805              :     }
    2806              :   }
    2807            7 : }
    2808              : 
    2809              : static long
    2810           21 : use_basis(long d_K, long f) { return (d_K<=10 || (d_K<=30 && f<=5000)); }
    2811              : 
    2812              : static long
    2813            7 : use_factor(ulong f)
    2814            7 : { GEN fa = factoru(f), P = gel(fa, 1); return (P[lg(P)-1]<500); }
    2815              : 
    2816              : /* group structure, destroy gr */
    2817              : static GEN
    2818           63 : get_str(GEN gr)
    2819              : {
    2820           63 :   GEN z = gel(gr,2);
    2821           63 :   long i, j, l = lg(z);
    2822          154 :   for (i = j = 1; i < l; i++)
    2823           91 :     if (lgefint(gel(z, i)) > 2) gel(z,j++) = gel(z,i);
    2824           63 :   setlg(z, j); return z;
    2825              : }
    2826              : 
    2827              : static GEN
    2828           21 : cyc_real_MLL(GEN K, ulong p, long d_pow, long j0, long flag)
    2829              : {
    2830           21 :   ulong d_K = K_get_d(K), f = K_get_f(K), d_chi = K_get_dchi(K);
    2831           21 :   ulong n, n0 = 1, f0, n_el = d_pow, d = upowuu(p, d_pow), rank = n_el*d_chi;
    2832           21 :   GEN velg = const_vec(n_el, NULL), vellg = NULL;
    2833           21 :   GEN oldgr = mkvec2(gen_0, NULL), newgr = mkvec2(gen_0, NULL);
    2834           21 :   long *y0 = (long*)stack_calloc(sizeof(long)*rank*rank);
    2835              : 
    2836           21 :   if (DEBUGLEVEL>1)
    2837            0 :     err_printf("cyc_real_MLL:p=%ld d_pow=%ld deg(K)=%ld cond(K)=%ld g_K=%ld\n",
    2838              :         p, d_pow, d_K, f, K_get_g(K));
    2839           21 :   gel(K, 2) = get_chi(gel(K,1));
    2840           21 :   if (f-1 <= (d_K<<1)) flag |= USE_F;
    2841           21 :   else if (use_basis(d_K, f)) flag |= USE_BASIS;
    2842            7 :   else if (use_factor(f)) flag |= USE_FACTOR;
    2843            0 :   else flag |= USE_GALOIS_POL;
    2844           21 :   if (flag&USE_BASIS) K = vec_append(K, xi_data_basis(K));
    2845            7 :   else if (flag&USE_GALOIS_POL) K = vec_append(K, xi_data_galois(K));
    2846           21 :   f0 = f%p?f:f/p;
    2847           21 :   gel(velg, 1) = next_el_real(K, p, d_pow, mkvecsmall2(1, 1), j0, flag);
    2848           21 :   if (flag&USE_FULL_EL)
    2849              :   {
    2850            0 :     for (n=2; n<=n_el; n++)
    2851            0 :       gel(velg, n) = next_el_real(K, p, d_pow, gel(velg, n+1), j0, flag);
    2852            0 :     n0 = n_el;
    2853              :   }
    2854              : 
    2855           21 :   for (n=n0; n<=n_el; n++) /* loop while structure is unknown */
    2856              :   {
    2857           21 :     pari_sp av2 = avma;
    2858              :     long n_ell, m, M;
    2859              :     GEN y;
    2860              :     pari_timer ti;
    2861           21 :     if (DEBUGLEVEL>2) timer_start(&ti);
    2862           21 :     vellg = set_ell_real(K, velg, n, d_chi, d*d, f0, j0);
    2863           21 :     n_ell = lg(vellg) -1; /* equal to n*d_chi */
    2864           21 :     if (DEBUGLEVEL>2) timer_printf(&ti, "set_ell_real");
    2865           21 :     if (DEBUGLEVEL>3) err_printf("vel=%Ps\nvell=%Ps\n", velg, vellg);
    2866           21 :     if (n_ell==1)
    2867           14 :       real_MLL1(y0, K, p, d_pow, velg, vellg, j0);
    2868              :     else
    2869              :     {
    2870              :       GEN vG_K;
    2871            7 :       if (DEBUGLEVEL>2) timer_start(&ti);
    2872            7 :       vG_K = make_G_K(K, vellg);
    2873            7 :       if (DEBUGLEVEL>2) timer_printf(&ti, "make_G_K");
    2874            7 :       if (lgefint(gmael(vellg, n_ell, 1))<=3 || (flag&SAVE_MEMORY))
    2875            7 :         real_MLL(y0, K, p, d_pow, n, velg, vellg, vG_K, j0);
    2876              :       else
    2877            0 :         real_MLLn(y0, K, p, d_pow, n, velg, vellg, vG_K, j0);
    2878              :     }
    2879           21 :     set_avma(av2);
    2880           21 :     y = ary2mat(y0, n_ell);
    2881           21 :     if (DEBUGLEVEL>3) err_printf("y=%Ps\n", y);
    2882           21 :     y = ZM_snf(y);
    2883           21 :     if (DEBUGLEVEL>3) err_printf("y=%Ps\n", y);
    2884           21 :     y = make_p_part(y, p, d_pow);
    2885           21 :     if (DEBUGLEVEL>3) err_printf("y=%Ps\n", y);
    2886           21 :     newgr = structure_MLL(y, d_pow);
    2887           21 :     if (DEBUGLEVEL>3)
    2888            0 :       err_printf("d_pow=%ld d_chi=%ld old=%Ps new=%Ps\n",d_pow,d_chi,oldgr,newgr);
    2889           21 :     if (equalsi(d_pow*d_chi, gel(newgr, 1))) break;
    2890            0 :     if ((m = find_del_el(&oldgr, newgr, n, n_el, d_chi)))
    2891            0 :     { M = m = delete_el(velg, m); n--; }
    2892              :     else
    2893            0 :     { M = n+1; m = n; }
    2894            0 :     gel(velg, M) = next_el_real(K, p, d_pow, gel(velg, m), j0, flag);
    2895              :   }
    2896           21 :   return get_str(newgr);
    2897              : }
    2898              : 
    2899              : static GEN
    2900            0 : cyc_buch(long dK, GEN p, long d_pow)
    2901              : {
    2902            0 :   GEN z = Buchquad(stoi(dK), 0.0, 0.0, 0), cyc = gel(z,2);
    2903            0 :   long i, l = lg(cyc);
    2904            0 :   if (Z_pval(gel(z,1), p) != d_pow) pari_err_BUG("subcyclopclgp [Buchquad]");
    2905            0 :   for (i = 1; i < l; i++)
    2906              :   {
    2907            0 :     long x = Z_pval(gel(cyc, i), p); if (!x) break;
    2908            0 :     gel(cyc, i) = utoipos(x);
    2909              :   }
    2910            0 :   setlg(cyc, i); return cyc;
    2911              : }
    2912              : 
    2913              : static void
    2914            0 : verbose_output(GEN K, GEN p, long pow, long j)
    2915              : {
    2916            0 :   long d = K_get_d(K), f = K_get_f(K), s = K_get_s(K), d_chi = K_get_dchi(K);
    2917            0 :   err_printf("|A_K_psi|=%Ps^%ld, psi=chi^%ld, d_psi=%ld, %s,\n\
    2918              :     [K:Q]=%ld, [f,H]=[%ld, %Ps]\n",
    2919            0 :     p,pow*d_chi,j,d_chi,s?"real":"imaginary",d,f,zv_to_ZV(gmael3(K,1,1,1)));
    2920            0 : }
    2921              : 
    2922              : static int
    2923        35091 : cyc_real_pre(GEN K, GEN xi, ulong p, ulong j, long el)
    2924              : {
    2925        35091 :   pari_sp av = avma;
    2926        35091 :   ulong i, d_K, x = 1;
    2927        35091 :   GEN e_chi = get_e_chi(K, j, p, &d_K);
    2928              : 
    2929        35091 :   xi++;
    2930      1254827 :   for (i = 0; i < d_K; i++) x = Fl_mul(x, Fl_powu(xi[i], e_chi[i], el), el);
    2931        35091 :   return gc_ulong(av, Fl_powu(x, (el-1)/p, el));
    2932              : }
    2933              : 
    2934              : /* return vec[-1,[],0], vec[0,[],0], vec[1,[1],0], vec[2,[1,1],0] etc */
    2935              : static GEN
    2936        26579 : cyc_real_ss(GEN K, GEN xi, ulong p, long j, long pow, long el, ulong pn, long flag)
    2937              : {
    2938        26579 :   ulong d_chi = K_get_dchi(K);
    2939        26579 :   if (cyc_real_pre(K, xi, pn, j, el) == 1) return NULL; /* not determined */
    2940        21273 :   if (--pow==0) return mkvec3(gen_0, nullvec(), gen_0); /* trivial */
    2941          105 :   if (DEBUGLEVEL) verbose_output(K, utoi(p), pow, j);
    2942          105 :   if (flag&USE_MLL)
    2943              :   {
    2944           21 :     pari_sp av = avma;
    2945           21 :     GEN gr = (K_get_d(K) == 2)? cyc_buch(K_get_f(K), utoi(p), pow)
    2946           21 :                                : cyc_real_MLL(K, p, pow, j, flag);
    2947           21 :     return gc_GEN(av, mkvec3(utoipos(d_chi * pow), gr, gen_0));
    2948              :   }
    2949           84 :   if (pow==1) return mkvec3(utoi(d_chi), onevec(d_chi), gen_0);
    2950           21 :   return mkvec3(utoi(pow*d_chi), nullvec(), gen_0);
    2951              : }
    2952              : 
    2953              : static GEN
    2954         5145 : cyc_real_ll(GEN K, GEN xi, GEN p, long j, long pow, GEN el, GEN pn, long flag)
    2955              : {
    2956         5145 :   pari_sp av = avma;
    2957         5145 :   ulong i, d_K = K_get_d(K), d_chi = K_get_dchi(K);
    2958         5145 :   GEN e_chi = get_e_chi_ll(K, j, pn), x = gen_1;
    2959              : 
    2960         5145 :   xi++;
    2961       246785 :   for (i = 0; i < d_K; i++)
    2962       241640 :     x = Fp_mul(x, Fp_pow(gel(xi, i), gel(e_chi, i), el), el);
    2963         5145 :   x = Fp_pow(x, diviiexact(subiu(el, 1), pn), el); /* x = x^(el-1)/pn mod el */
    2964         5145 :   set_avma(av); if (equali1(x)) return NULL; /* not determined */
    2965         5145 :   if (--pow==0) return mkvec3(gen_0, nullvec(), gen_0); /* trivial */
    2966            0 :   if (DEBUGLEVEL) verbose_output(K, p, pow, j);
    2967            0 :   if (flag&USE_MLL)
    2968            0 :     pari_err_IMPL(stack_sprintf("flag=%ld for large prime", USE_MLL));
    2969            0 :   if (pow==1) return mkvec3(utoi(d_chi), onevec(d_chi), gen_0);
    2970            0 :   return mkvec3(utoi(pow*d_chi), nullvec(), gen_0);
    2971              : }
    2972              : 
    2973              : /* xi[1+i] = xi^(g^i), 0 <= i <= d-1 */
    2974              : static GEN
    2975        13797 : xi_conj_s(GEN K, ulong el)
    2976              : {
    2977        13797 :   pari_sp av = avma;
    2978        13797 :   GEN  H = K_get_H(K);
    2979        13797 :   long d = K_get_d(K), f = K_get_f(K), h = K_get_h(K), g = K_get_g(K);
    2980        13797 :   long i, gi = 1, z = Fl_powu(pgener_Fl(el), (el-1)/f, el);
    2981        13797 :   GEN vz = Fl_powers(z, f, el)+1, xi = cgetg(d+1, t_VECSMALL);
    2982              : 
    2983       372953 :   for (i=1; i<=d; i++)
    2984              :   {
    2985       359156 :     long j, x = 1;
    2986    170777852 :     for (j=1; j<=h; j++)
    2987    170418696 :       x = Fl_mul(x, vz[Fl_mul(H[j], gi, f)]-1, el);
    2988       359156 :     xi[i] = x;
    2989       359156 :     gi = Fl_mul(gi, g, f);
    2990              :   }
    2991        13797 :   return gc_GEN(av, xi);
    2992              : }
    2993              : 
    2994              : static GEN
    2995         1673 : xi_conj_l(GEN K, GEN el)
    2996              : {
    2997         1673 :   pari_sp av = avma;
    2998         1673 :   GEN  H = K_get_H(K);
    2999         1673 :   long d = K_get_d(K), f = K_get_f(K), h = K_get_h(K), g = K_get_g(K);
    3000         1673 :   long i, gi = 1;
    3001         1673 :   GEN z = Fp_pow(pgener_Fp(el), diviuexact(subiu(el, 1), f), el);
    3002         1673 :   GEN vz = Fp_powers(z, f, el)+1, xi = cgetg(d+1, t_VEC);
    3003              : 
    3004        70462 :   for (i=1; i<=d; i++)
    3005              :   {
    3006              :     long j;
    3007        68789 :     GEN x = gen_1;
    3008      6756043 :     for (j=1; j<=h; j++)
    3009      6687254 :       x = Fp_mul(x, subiu(gel(vz, Fl_mul(H[j], gi, f)), 1), el);
    3010        68789 :     gel(xi, i) = x;
    3011        68789 :     gi = Fl_mul(gi, g, f);
    3012              :   }
    3013         1673 :   return gc_GEN(av, xi);
    3014              : }
    3015              : 
    3016              : static GEN
    3017        10164 : pclgp_cyc_real(GEN K, GEN p, long max_pow, long flag)
    3018              : {
    3019        10164 :   const long NUM_EL = 20;
    3020        10164 :   GEN C = gel(K, 5);
    3021        10164 :   long f_K = K_get_f(K), n_conj = K_get_nconj(K);
    3022        10164 :   long i, pow, n_el, n_done = 0;
    3023        10164 :   GEN gr = nullvec(), Done = const_vecsmall(n_conj, 0), xi;
    3024        10164 :   long first = 1;
    3025              : 
    3026        10290 :   for (pow=1; pow<=max_pow; pow++)
    3027              :   {
    3028        10290 :     GEN pn = powiu(p, pow), fpn = muliu(pn, f_K), el = addiu(fpn, 1);
    3029       109753 :     for (n_el = 0; n_el < NUM_EL; el = addii(el, fpn))
    3030              :     {
    3031              :       ulong uel;
    3032       109627 :       if (!BPSW_psp(el)) continue;
    3033        15470 :       n_el++; uel = itou_or_0(el);
    3034        15470 :       if (uel)
    3035              :       {
    3036        13797 :         xi = xi_conj_s(K, uel);
    3037        13797 :         if (first && n_conj > 10) /* mark trivial chi-part */
    3038              :         {
    3039         8715 :           for (i = 1; i <= n_conj; i++)
    3040              :           {
    3041         8512 :             if (cyc_real_pre(K, xi, p[2], C[i], uel) == 1) continue;
    3042         8260 :             Done[i] = 1;
    3043         8260 :             if (++n_done == n_conj) return gr;
    3044              :           }
    3045          203 :           first = 0; continue;
    3046              :         }
    3047              :       }
    3048              :       else
    3049         1673 :         xi = xi_conj_l(K, el);
    3050        55132 :       for (i = 1; i <= n_conj; i++)
    3051              :       {
    3052              :         GEN z;
    3053        50029 :         if (Done[i]) continue;
    3054        31724 :         if (uel)
    3055        26579 :           z = cyc_real_ss(K, xi, p[2], C[i], pow, uel, itou(pn), flag);
    3056              :         else
    3057         5145 :           z = cyc_real_ll(K, xi, p, C[i], pow, el, pn, flag);
    3058        31724 :         if (!z) continue;
    3059        26418 :         Done[i] = 1;
    3060        26418 :         if (!isintzero(gel(z, 1))) gr = vec_append(gr, z);
    3061        26418 :         if (++n_done == n_conj) return gr;
    3062              :       }
    3063              :     }
    3064              :   }
    3065            0 :   pari_err_BUG("pclgp_cyc_real: max_pow is not enough");
    3066              :   return NULL; /*LCOV_EXCL_LINE*/
    3067              : }
    3068              : 
    3069              : /* return (el, g_el) */
    3070              : static GEN
    3071           56 : next_el_imag(GEN elg, long f)
    3072              : {
    3073           56 :   long el = elg[1];
    3074           56 :   if (odd(f)) f<<=1;
    3075          140 :   while (!uisprime(el+=f));
    3076           56 :   return mkvecsmall2(el, pgener_Fl(el));
    3077              : }
    3078              : 
    3079              : /* return (ell, g_ell) */
    3080              : static GEN
    3081           70 : next_ell_imag(GEN ellg, GEN df0l)
    3082              : {
    3083           70 :   GEN ell = gel(ellg, 1);
    3084          770 :   while (!BPSW_psp(ell = addii(ell, df0l)));
    3085           70 :   return mkvec2(ell, pgener_Fp(ell));
    3086              : }
    3087              : 
    3088              : static GEN
    3089           56 : set_ell_imag(GEN velg, long n, long d_chi, GEN df0)
    3090              : {
    3091           56 :   long i, n_ell = n*d_chi;
    3092           56 :   GEN z = cgetg(n_ell + 1, t_VEC);
    3093           56 :   GEN df0l = shifti(df0, 1), ellg = mkvec2(gen_1, gen_1);
    3094          126 :   for (i=1; i<=n; i++) df0l = muliu(df0l, gel(velg, i)[1]);
    3095          126 :   for (i=1; i<=n_ell; i++) ellg = gel(z, i)= next_ell_imag(ellg, df0l);
    3096           56 :   return z;
    3097              : }
    3098              : 
    3099              : /* U(X)=u(x)+u(X)*X^f+...+f(X)*X^((m-1)f) or u(x)-u(X)*X^f+...
    3100              :  * U(X)V(X)=u(X)V(X)(1+X^f+...+X^((m-1)f))
    3101              :  *         =w_0+w_1*X+...+w_{f+el-3}*X^(f+el-3)
    3102              :  * w_i (1 <= i <= f+el-2) are needed.
    3103              :  * w_{f+el-2}=0 if el-1 == f.
    3104              :  * W_i = w_i + w_{i+el-1} (1 <= i <= f-1). */
    3105              : static GEN
    3106           85 : gauss_Flx_mul(ulong f, GEN elg, GEN ellg)
    3107              : {
    3108           85 :   pari_sp av = avma;
    3109           85 :   ulong el = elg[1], g_el= elg[2];
    3110           85 :   ulong el_1 = el-1, f2 = f<<1, lv = el_1, lu = f, m = el_1/f;
    3111           85 :   ulong ell = itou(gel(ellg, 1)), g_ell = itou(gel(ellg, 2));
    3112           85 :   ulong z_2f = Fl_powu(g_ell, (ell - 1) / f2, ell);
    3113           85 :   ulong z_el = Fl_powu(g_ell, (ell - 1) / el, ell);
    3114              :   ulong i, i2, gi;
    3115           85 :   GEN W = cgetg(f+1, t_VECSMALL), vz_2f, vz_el;
    3116           85 :   GEN u = cgetg(lu+2, t_VECSMALL), v = cgetg(lv+2, t_VECSMALL), w0;
    3117              : 
    3118           85 :   u[1] = evalsigne(1);
    3119           85 :   v[1] = evalsigne(1);
    3120           85 :   vz_2f = Fl_powers(z_2f, f2-1, ell);
    3121           85 :   vz_el = Fl_powers(z_el, el_1, ell);
    3122       528459 :   for (i=i2=0; i<lu; i++)
    3123              :   {
    3124              :     long j2; /* i2=(i*i)%f2, gi=g_el^i */
    3125       528374 :     j2 = i2?f2-i2:i2;
    3126       528374 :     u[2+i] = vz_2f[1+j2];
    3127       528374 :     if ((i2+=i+i+1)>=f2) i2-=f2; /* same as i2%=f2 */
    3128              :   }
    3129      1600537 :   for (gi=1,i=i2=0; i<lv; i++)
    3130              :   {
    3131      1600452 :     v[2+i] = Fl_mul(vz_2f[1+i2], vz_el[1+gi], ell);
    3132      1600452 :     gi = Fl_mul(gi, g_el, el);
    3133      1600452 :     if ((i2+=i+i+1)>=f2) i2%=f2; /* i2-=f2 does not work */
    3134              :   }
    3135           85 :   w0 = Flx_mul(u, v, ell) + 1;
    3136           85 :   if (m==1)
    3137              :   { /* el_1=f */
    3138            0 :     for (i=1; i<f; i++) W[i] = Fl_add(w0[i], w0[i+lv], ell);
    3139            0 :     W[f] = w0[f];
    3140              :   }
    3141              :   else
    3142              :   {
    3143           85 :     ulong start = 1+f, end = f+el-1;
    3144           85 :     GEN w = cgetg(end+1, t_VECSMALL);
    3145      2128826 :     for (i=1; i<end; i++) w[i] = w0[i];
    3146           85 :     w[end] = 0;
    3147          360 :     for (i=1; i<m; i++, start+=f)
    3148          550 :       w = both_odd(f,i)? Flv_shift_sub(w, w0, ell, start, end)
    3149          275 :                        : Flv_shift_add(w, w0, ell, start, end);
    3150       528459 :     for (i=0; i<f; i++) W[1+i] = Fl_add(w[1+i], w[1+i+lv], ell);
    3151              :   }
    3152       528374 :   for (i=i2=1; i<f; i++)
    3153              :   {
    3154       528289 :     W[i]=Fl_mul(W[1+i], vz_2f[1+i2], ell);
    3155       528289 :     if ((i2+=i+i+1)>=f2) i2%=f2;
    3156              :   }
    3157              :   /* W[r]=tau_{LL}^{sigma_r}, 1<= r <= f-1 */
    3158           85 :   return gc_GEN(av, Flv_to_ZV(W));
    3159              : }
    3160              : 
    3161              : static GEN
    3162           90 : gauss_ZX_mul(ulong f, GEN elg, GEN ellg)
    3163              : {
    3164           90 :   pari_sp av = avma, av2;
    3165              :   ulong el, g_el, el_1, f2, lv, lu, m, i, i2, gi;
    3166           90 :   GEN  ell = gel(ellg, 1), g_ell, ell_1, z_2f, z_el, W, vz_2f, vz_el, u, v, w0;
    3167              : 
    3168           90 :   if (lgefint(ell) == 3) return gauss_Flx_mul(f, elg, ellg);
    3169            5 :   g_ell = gel(ellg, 2); ell_1 = subiu(ell, 1);
    3170            5 :   el = elg[1]; g_el = elg[2]; el_1 = el-1;
    3171            5 :   f2 = f<<1; lv=el_1; lu=f; m=el_1/f;
    3172            5 :   z_2f = Fp_pow(g_ell, diviuexact(ell_1, f2), ell);
    3173            5 :   vz_2f = Fp_powers(z_2f, f2-1, ell);
    3174            5 :   W = cgetg(f+1, t_VEC);
    3175            5 :   av2 = avma;
    3176            5 :   z_el = Fp_pow(g_ell, diviuexact(ell_1, el), ell);
    3177            5 :   vz_el = Fp_powers(z_el, el_1, ell);
    3178            5 :   u = cgetg(lu+2, t_POL); u[1] = evalsigne(1) | evalvarn(0);
    3179            5 :   v = cgetg(lv+2, t_POL); v[1] = evalsigne(1) | evalvarn(0);
    3180        35264 :   for (gi=1,i=i2=0; i<lu; i++)
    3181              :   {
    3182              :     long j2; /* i2=(i*i)%f2, gi=g_el^i */
    3183        35259 :     j2 = i2?f2-i2:i2;
    3184        35259 :     gel(u, 2+i) = gel(vz_2f, 1+j2);
    3185        35259 :     if ((i2+=i+i+1)>=f2) i2-=f2;
    3186              :   }
    3187        82787 :   for (gi=1,i=i2=0; i<lv; i++)
    3188              :   {
    3189        82782 :     gel(v, 2+i) = Fp_mul(gel(vz_2f, 1+i2), gel(vz_el, 1+gi), ell);
    3190        82782 :     gi = Fl_mul(gi, g_el, el);
    3191        82782 :     if ((i2+=i+i+1)>=f2) i2%=f2;
    3192              :   }
    3193            5 :   w0 = gc_upto(av2, FpX_mul(u, v, ell)) + 1; av2 = avma;
    3194            5 :   if (m==1)
    3195              :   {
    3196            0 :     for (i=1; i < f; i++) gel(W,i) = Fp_add(gel(w0, i), gel(w0, i+lv), ell);
    3197            0 :     gel(W, f) = gel(w0, f);
    3198              :   }
    3199              :   else
    3200              :   {
    3201            5 :     ulong start = 1+f, end = f+el-1;
    3202            5 :     GEN w = cgetg(end+1, t_VEC);
    3203       118041 :     for (i=1; i<end; i++) gel(w, i) = gel(w0, i);
    3204            5 :     gel(w, end) = gen_0;
    3205           15 :     for (i=1; i<m; i++, start+=f)
    3206              :     {
    3207           13 :       w = both_odd(f,i)? FpV_shift_sub(w, w0, ell, start, end)
    3208           10 :                        : FpV_shift_add(w, w0, ell, start, end);
    3209           10 :       if ((i & 7) == 0) w = gc_GEN(av2, w);
    3210              :     }
    3211        35264 :     for (i = 1; i <= f; i++) gel(W, i) = addii(gel(w, i), gel(w, i+lv));
    3212              :   }
    3213        35259 :   for (i = i2 = 1; i < f; i++)
    3214              :   {
    3215        35254 :     gel(W, i) = Fp_mul(gel(W, 1+i), gel(vz_2f, 1+i2), ell);
    3216        35254 :     if ((i2+=i+i+1) >= f2) i2 %= f2;
    3217              :   }
    3218            5 :   return gc_GEN(av, W);  /* W[r]=tau_{LL}^{sigma_r}, 1<= r <= f-1 */
    3219              : }
    3220              : 
    3221              : /* fast but consumes memory */
    3222              : static GEN
    3223            4 : gauss_el_vell(ulong f, GEN elg, GEN vellg, GEN vz_2f)
    3224              : {
    3225            4 :   pari_sp av = avma, av2;
    3226            4 :   ulong el = elg[1], g_el = elg[2], el_1 = el-1;
    3227            4 :   ulong lv=el_1, f2=f<<1, lu=f, m=el_1/f;
    3228            4 :   GEN W = cgetg(f+1, t_VEC), vz_el, u, v, w0, M;
    3229              :   ulong i, i2, gi;
    3230              : 
    3231            4 :   av2 = avma;
    3232            4 :   vz_el = vz_vell(el, vellg, &M);
    3233            4 :   u = cgetg(lu+2, t_POL); u[1] = evalsigne(1) | evalvarn(0);
    3234            4 :   v = cgetg(lv+2, t_POL); v[1] = evalsigne(1) | evalvarn(0);
    3235        25554 :   for (i=i2=0; i<lu; i++)
    3236              :   {
    3237              :     long j2; /* i2=(i*i)%f2, gi=g_el^i */
    3238        25550 :     j2 = i2?f2-i2:i2;
    3239        25550 :     gel(u, 2+i) = gel(vz_2f, 1+j2);
    3240        25550 :     if ((i2+=i+i+1)>=f2) i2%=f2;
    3241              :   }
    3242        86874 :   for (gi=1,i=i2=0; i<lv; i++)
    3243              :   {
    3244        86870 :     gel(v, 2+i) = Fp_mul(gel(vz_2f, 1+i2), gel(vz_el, 1+gi), M);
    3245        86870 :     gi = Fl_mul(gi, g_el, el);
    3246        86870 :     if ((i2+=i+i+1)>=f2) i2%=f2;
    3247              :   }
    3248            4 :   M = gclone(M);
    3249            4 :   w0 = gc_upto(av2, FpX_mul(u, v, M)) + 1;
    3250            4 :   u = M; M = icopy(M); gunclone(u);
    3251            4 :   av2 = avma;
    3252            4 :   if (m==1)
    3253              :   { /* el_1=f */
    3254            0 :     for (i=1; i < f; i++) gel(W,i) = Fp_add(gel(w0, i), gel(w0, i+lv), M);
    3255            0 :     gel(W, f) = gel(w0, f);
    3256              :   }
    3257              :   else
    3258              :   {
    3259            4 :     ulong start = 1+f, end = f+el-1;
    3260            4 :     GEN w = cgetg(end+1, t_VEC);
    3261       112420 :     for (i=1; i<end; i++) gel(w, i) = gel(w0, i);
    3262            4 :     gel(w, end) = gen_0;
    3263           19 :     for (i=1; i<m; i++, start+=f)
    3264              :     {
    3265           22 :       w = both_odd(f,i)? FpV_shift_sub(w, w0, M, start, end)
    3266           15 :                        : FpV_shift_add(w, w0, M, start, end);
    3267           15 :       if ((i & 7) == 0) w = gc_GEN(av2, w);
    3268              :     }
    3269        25554 :     for (i = 1; i <= f; i++) gel(W, i) = Fp_add(gel(w, i), gel(w, i+lv), M);
    3270              :   }
    3271        25550 :   for (i = i2 = 1; i < f; i++)
    3272              :   {
    3273        25546 :     gel(W, i) = Fp_mul(gel(W, 1+i), gel(vz_2f, 1+i2), M);
    3274        25546 :     if ((i2+=i+i+1) >= f2) i2 %= f2;
    3275              :   }
    3276            4 :   return gc_GEN(av, W);  /* W[r]=tau_{LL}^{sigma_r}, 1<= r <= f-1 */
    3277              : }
    3278              : 
    3279              : static GEN
    3280           94 : norm_chi(GEN K, GEN TAU, ulong p, long d_pow, GEN ell, long j0)
    3281              : {
    3282           94 :   pari_sp av = avma;
    3283           94 :   GEN H = K_get_H(K);
    3284           94 :   ulong d_K, f_K = K_get_f(K), h = K_get_h(K), g_K = K_get_g(K);
    3285           94 :   ulong i, j, gi, pd = upowuu(p, d_pow), d_chi = K_get_dchi(K);
    3286           94 :   GEN z = const_vec(d_chi, gen_1);
    3287           94 :   GEN e_chi = get_e_chi(K, j0, pd, &d_K);
    3288              : 
    3289         1420 :   for (gi=1, i=0; i<d_K; i++)
    3290              :   {
    3291         1326 :     GEN y = gen_1;
    3292       230862 :     for (j=1; j<=h; j++)
    3293       229536 :       y = Fp_mul(y, gel(TAU, Fl_mul(gi, H[j], f_K)), ell);
    3294         1326 :     gi = Fl_mul(gi, g_K, f_K);
    3295         2652 :     for (j=1; j<=d_chi; j++)
    3296              :     {
    3297         1326 :       GEN y2 = Fp_powu(y, e_chi[(i+j-1)%d_K], ell);
    3298         1326 :       gel(z, j) = Fp_mul(gel(z, j), y2, ell);
    3299              :     }
    3300              :   }
    3301           94 :   return gc_GEN(av, z);
    3302              : }
    3303              : 
    3304              : static void
    3305            2 : imag_MLLn(long *y, GEN K, ulong p, long d_pow, long n,
    3306              :     GEN velg, GEN vellg, long j0)
    3307              : {
    3308            2 :   long f = K_get_f(K), d = upowuu(p, d_pow), row = lg(vellg)-1, i, j, k, nz;
    3309            2 :   GEN g, z, M, vz_2f = vz_vell(f << 1, vellg, &M);
    3310            6 :   for (i=1; i<=n; i++)
    3311              :   {
    3312            4 :     pari_sp av = avma;
    3313            4 :     GEN elg = gel(velg, i);
    3314            4 :     if (DEBUGLEVEL>1) err_printf("(f,el-1)=(%ld,%ld*%ld)\n", f,(elg[1]-1)/f,f);
    3315            4 :     g = gauss_el_vell(f, elg, vellg, vz_2f);
    3316            4 :     z = norm_chi(K, g, p, d_pow, M, j0);
    3317            4 :     nz = lg(z)-1;
    3318            8 :     for (k = 1; k <= nz; k++)
    3319           12 :       for (j = 1; j <= row; j++)
    3320            8 :         y[(j-1)*row+(i-1)*nz+k-1] = get_y(gel(z, k), gel(vellg, j), d);
    3321            4 :     set_avma(av);
    3322              :   }
    3323            2 : }
    3324              : 
    3325              : static void
    3326           42 : imag_MLL1(long *y, GEN K, ulong p, long d_pow, GEN velg, GEN vellg, long j0)
    3327              : {
    3328           42 :   long f = K_get_f(K), d = upowuu(p, d_pow);
    3329           42 :   GEN elg = gel(velg, 1), ellg = gel(vellg, 1), ell = gel(ellg, 1), g, z;
    3330              : 
    3331           42 :   if (DEBUGLEVEL>1) err_printf("(f,el-1)=(%ld,%ld*%ld)\n", f, (elg[1]-1)/f, f);
    3332           42 :   g = gauss_ZX_mul(f, elg, ellg);
    3333           42 :   z = norm_chi(K, g, p, d_pow, ell, j0);
    3334           42 :   y[0] = get_y(gel(z, 1), ellg, d);
    3335           42 : }
    3336              : 
    3337              : static void
    3338           12 : imag_MLL(long *y, GEN K, ulong p, long d_pow, long n, GEN velg, GEN vellg,
    3339              :     long j0)
    3340              : {
    3341           12 :   pari_sp av = avma;
    3342           12 :   long i, j, f = K_get_f(K), d = upowuu(p, d_pow), row = lg(vellg)-1;
    3343              : 
    3344           36 :   for (j=1; j<=row; j++)
    3345              :   {
    3346           24 :     GEN ellg = gel(vellg, j), ell = gel(ellg, 1);
    3347           72 :     for (i=1; i<=n; i++)
    3348              :     {
    3349           48 :       GEN elg = gel(velg, i), g, z;
    3350              :       ulong k, nz;
    3351           48 :       if (DEBUGLEVEL>1) err_printf("(f,el-1)=(%ld,%ld*%ld)\n",f,(elg[1]-1)/f,f);
    3352           48 :       g = gauss_ZX_mul(f, elg, ellg);
    3353           48 :       z = norm_chi(K, g, p, d_pow, ell, j0);
    3354           48 :       nz = lg(z)-1;
    3355           96 :       for (k = 1; k <= nz; k++)
    3356           48 :         y[(j-1)*row+(i-1)*nz+k-1] = get_y(gel(z, k), ellg, d);
    3357           48 :       set_avma(av);
    3358              :     }
    3359              :   }
    3360           12 : }
    3361              : 
    3362              : /* return an upper bound >= 0 if one was found, otherwise return -1.
    3363              :  * set chi-part to be (1) if chi is Teichmuller character.
    3364              :  * B_{1,omega^(-1)} is not p-adic integer. */
    3365              : static GEN
    3366           42 : cyc_imag_MLL(GEN K, ulong p, long d_pow, long j, long flag)
    3367              : {
    3368           42 :   long f = K_get_f(K), d_chi = K_get_dchi(K);
    3369           42 :   long n, n0 = 1, n_el = d_pow, d = upowuu(p, d_pow), rank = n_el*d_chi;
    3370           42 :   GEN df0, velg = const_vec(n_el, NULL), vellg = NULL;
    3371           42 :   GEN oldgr = mkvec2(gen_0, NULL), newgr = mkvec2(gen_0, NULL);
    3372           42 :   long *y0 = (long*)stack_calloc(sizeof(long)*rank*rank);
    3373              : 
    3374           42 :   if (DEBUGLEVEL>1)
    3375            0 :     err_printf("cyc_imag_MLL:p=%ld d_pow=%ld deg(K)=%ld cond(K)=%ld avma=%ld\n",
    3376              :         p, d_pow, K_get_d(K), f, avma);
    3377           42 :   df0 = muluu(d, f%p?f:f/p);
    3378           42 :   gel(velg, 1) = next_el_imag(mkvecsmall2(1, 1), f);
    3379           42 :   if (flag&USE_FULL_EL)
    3380              :   {
    3381            0 :     for (n=2; n<=n_el; n++) gel(velg, n) = next_el_imag(gel(velg, n-1), f);
    3382            0 :     n0 = n_el;
    3383              :   }
    3384           56 :   for (n=n0; n<=n_el; n++) /* loop while structure is unknown */
    3385              :   {
    3386           56 :     pari_sp av2 = avma;
    3387              :     pari_timer ti;
    3388              :     long n_ell, m, M;
    3389              :     GEN y;
    3390           56 :     vellg = set_ell_imag(velg, n, d_chi, df0);
    3391           56 :     n_ell = lg(vellg)-1;  /* equal to n*d_chi */
    3392           56 :     if (DEBUGLEVEL>2) err_printf("velg=%Ps\nvellg=%Ps\n", velg, vellg);
    3393           56 :     if (DEBUGLEVEL>2) timer_start(&ti);
    3394           56 :     if (n_ell==1)
    3395           42 :       imag_MLL1(y0, K, p, d_pow, velg, vellg, j);
    3396           14 :     else if (lgefint(gmael(vellg, n, 1))<=3 || (flag&SAVE_MEMORY))
    3397           12 :       imag_MLL(y0, K, p, d_pow, n, velg, vellg, j);
    3398              :     else
    3399            2 :       imag_MLLn(y0, K, p, d_pow, n, velg, vellg, j);
    3400           56 :     set_avma(av2);
    3401           56 :     if (DEBUGLEVEL>2) timer_printf(&ti, "gauss sum");
    3402           56 :     y = ary2mat(y0, n_ell);
    3403           56 :     if (DEBUGLEVEL>3) err_printf("y=%Ps\n", y);
    3404           56 :     y = ZM_snf(y);
    3405           56 :     if (DEBUGLEVEL>3) err_printf("y=%Ps\n", y);
    3406           56 :     y = make_p_part(y, p, d_pow);
    3407           56 :     if (DEBUGLEVEL>3) err_printf("y=%Ps\n", y);
    3408           56 :     newgr = structure_MLL(y, d_pow);
    3409           56 :     if (DEBUGLEVEL>3)
    3410            0 :       err_printf("d_pow=%ld d_chi=%ld old=%Ps new=%Ps\n",d_pow,d_chi,oldgr,newgr);
    3411           56 :     if (equalsi(d_pow*d_chi, gel(newgr, 1))) break;
    3412           14 :     if ((m = find_del_el(&oldgr, newgr, n, n_el, d_chi)))
    3413            0 :     { M = m = delete_el(velg, m); n--; }
    3414              :     else
    3415           14 :     { M = n+1; m = n; }
    3416           14 :     gel(velg, M) = next_el_imag(gel(velg, m), f);
    3417              :   }
    3418           42 :   return get_str(newgr);
    3419              : }
    3420              : 
    3421              : /* When |A_psi|=p^e, A_psi=(p^e1,...,p^er) (psi=chi^j),
    3422              :  *  return vec[e, [e1, ... , er], 1].
    3423              :  * If gr str is not determined, return vec[e, [], 1].
    3424              :  * If |A_chi|=1, return vec[0, [], 1].
    3425              :  * If |A_chi|=p, return vec[1, [1], 1].
    3426              :  * If e is not determined, return vec[-1, [], 1].
    3427              :  * If psi is Teichmuller, return vec[0, [], 1].
    3428              :  * B_{1,omega^(-1)} is not p-adic integer. */
    3429              : static GEN
    3430        26334 : cyc_imag(GEN K, GEN B, GEN p, long j, GEN powp, long flag)
    3431              : {
    3432        26334 :   pari_sp av = avma;
    3433        26334 :   GEN MinPol = gel(K, 3), Chi = gel(K, 2), B1, B2, gr;
    3434        26334 :   long x, d_K = K_get_d(K), f_K = K_get_f(K), d_chi = K_get_dchi(K);
    3435              : 
    3436        26334 :   if (f_K == d_K+1 && equaliu(p, f_K) && j == 1) /* Teichmuller */
    3437           77 :     return mkvec3(gen_0, nullvec(), gen_1);
    3438        26257 :   B1 = FpX_rem(ZX_ber_conj(B, j, d_K), MinPol, powp);
    3439        26257 :   B2 = FpX_rem(ZX_ber_den(Chi, j, d_K), MinPol, powp);
    3440        26257 :   if (degpol(B1)<0 || degpol(B2)<0)
    3441              :   {
    3442            0 :     set_avma(av);
    3443            0 :     return mkvec3(gen_m1, nullvec(), gen_1); /* B=0(mod p^pow) */
    3444              :   }
    3445        26257 :   x = ZX_pval(B1, p) - ZX_pval(B2, p);
    3446        26257 :   set_avma(av);
    3447        26257 :   if (x<0) pari_err_BUG("subcyclopclgp [Bernoulli number]");
    3448        26257 :   if (DEBUGLEVEL && x) verbose_output(K, p, x, j);
    3449        26257 :   if (x==0) return mkvec3(gen_0, nullvec(), gen_1); /* trivial */
    3450          588 :   if (x==1) return mkvec3(utoi(d_chi), onevec(d_chi), gen_1);
    3451          140 :   if ((flag&USE_MLL)==0) return mkvec3(utoi(x*d_chi), nullvec(), gen_1);
    3452           42 :   gr = d_K == 2? cyc_buch(-f_K, p, x): cyc_imag_MLL(K, itou(p), x, j, flag);
    3453           42 :   return gc_GEN(av, mkvec3(utoipos(d_chi * x), gr, gen_1));
    3454              : }
    3455              : 
    3456              : /* handle representatives of all injective characters, d_chi=[Q_p(zeta_d):Q_p],
    3457              :  * d=d_K */
    3458              : static GEN
    3459        10080 : pclgp_cyc_imag(GEN K, GEN p, long start_pow, long max_pow, long flag)
    3460              : {
    3461        10080 :   GEN C = gel(K, 5), Chi = gel(K, 2);
    3462        10080 :   long n_conj = K_get_nconj(K), d_K = K_get_d(K), f_K = K_get_f(K);
    3463        10080 :   long i, pow, n_done = 0;
    3464        10080 :   GEN gr = nullvec(), Done = const_vecsmall(n_conj, 0);
    3465        10080 :   GEN B = zx_ber_num(Chi, f_K, d_K), B_num;
    3466              : 
    3467        10080 :   if (lgefint(p)==3 && n_conj>10) /* mark trivial chi-part by pre-calculation */
    3468              :   {
    3469          595 :     ulong up = itou(p);
    3470          595 :     GEN minpol = ZX_to_Flx(gel(K, 3), up);
    3471         7350 :     for (i=1; i<=n_conj; i++)
    3472              :     {
    3473         7168 :       pari_sp av = avma;
    3474              :       long degB;
    3475         7168 :       B_num = Flx_rem(Flx_ber_conj(B, C[i], d_K, up), minpol, up);
    3476         7168 :       degB = degpol(B_num);
    3477         7168 :       set_avma(av);
    3478         7168 :       if (degB<0) continue;
    3479         6937 :       Done[i] = 1;
    3480         6937 :       if (++n_done == n_conj) return gr;
    3481              :     }
    3482              :   }
    3483         9667 :   for (pow = start_pow; pow<=max_pow; pow++)
    3484              :   {
    3485         9667 :     GEN powp = powiu(p, pow);
    3486        27503 :     for (i = 1; i <= n_conj; i++)
    3487              :     {
    3488              :       GEN z;
    3489        27503 :       if (Done[i]) continue;
    3490        26334 :       z = cyc_imag(K, B, p, C[i], powp, flag);
    3491        26334 :       if (equalim1(gel(z, 1))) continue;
    3492        26334 :       Done[i] = 1;
    3493        26334 :       if (!isintzero(gel(z, 1))) gr = vec_append(gr, z);
    3494        26334 :       if (++n_done == n_conj) return gr;
    3495              :     }
    3496              :   }
    3497            0 :   pari_err_BUG("pclgp_cyc_imag: max_pow is not enough");
    3498              :   return NULL; /*LCOV_EXCL_LINE*/
    3499              : }
    3500              : 
    3501              : static GEN
    3502          392 : gather_part(GEN g, long sgn)
    3503              : {
    3504          392 :   long i, j, l = lg(g), ord = 0, flag = 1;
    3505          392 :   GEN z2 = cgetg(l, t_VEC);
    3506         1778 :   for (i = j = 1; i < l; i++)
    3507              :   {
    3508         1386 :     GEN t = gel(g,i);
    3509         1386 :     if (equaliu(gel(t, 3), sgn))
    3510              :     {
    3511          693 :       ord += itou(gel(t, 1));
    3512          693 :       if (lg(gel(t, 2)) == 1) flag = 0;
    3513          693 :       gel(z2, j++) = gel(t, 2);
    3514              :     }
    3515              :   }
    3516          392 :   if (flag==0 || ord==0) z2 = nullvec();
    3517              :   else
    3518              :   {
    3519          126 :     setlg(z2, j); z2 = shallowconcat1(z2);
    3520          126 :     ZV_sort_inplace(z2); vecreverse_inplace(z2);
    3521              :   }
    3522          392 :   return mkvec2(utoi(ord), z2);
    3523              : }
    3524              : 
    3525              : #ifdef DEBUG
    3526              : static void
    3527              : handling(GEN K)
    3528              : {
    3529              :   long d_K = K_get_d(K), f_K = K_get_f(K), s_K = K_get_s(K), g_K = K_get_g(K);
    3530              :   long d_chi = K_get_dchi(K);
    3531              :   err_printf("  handling %s cyclic subfield K,\
    3532              :       deg(K)=%ld, cond(K)=%ld g_K=%ld d_chi=%ld H=%Ps\n",
    3533              :       s_K? "a real": "an imaginary",d_K,f_K,g_K,d_chi,zv_to_ZV(gmael3(K,1,1,1)));
    3534              : }
    3535              : #endif
    3536              : 
    3537              : /* HH a t_VECSMALL listing group generators
    3538              :  * Aoki and Fukuda, LNCS vol.4076 (2006), 56-74. */
    3539              : static GEN
    3540          161 : pclgp(GEN p0, long f, GEN HH, long degF, long flag)
    3541              : {
    3542              :   long start_pow, max_pow, ip, lp, i, n_f;
    3543          161 :   GEN vH1, z, vData, cycGH, vp = typ(p0) == t_INT? mkvec(p0): p0;
    3544              : 
    3545          161 :   vH1 = GHinit(f, HH, &cycGH); n_f = lg(vH1)-1;
    3546              : #ifdef DEBUG
    3547              :   err_printf("F is %s, deg(F)=%ld, ", srh_1(HH)? "real": "imaginary", degF);
    3548              :   err_printf("cond(F)=%ld, G(F/Q)=%Ps\n",f, cycGH);
    3549              :   err_printf("F has %ld cyclic subfield%s except for Q.\n", n_f,n_f>1?"s":"");
    3550              : #endif
    3551              : 
    3552          161 :   lp = lg(vp); z = cgetg(lp, t_MAT);
    3553          357 :   for (ip = 1; ip < lp; ip++)
    3554              :   {
    3555          196 :     pari_sp av = avma;
    3556          196 :     long n_sub=0, n_chi=0;
    3557          196 :     GEN gr=nullvec(), p = gel(vp, ip), zi;
    3558              :     /* find conductor e of cyclic subfield K and set the subgroup HE of (Z/eZ)^*
    3559              :      * corresponding to K */
    3560          196 :     set_p_f(p, f, &start_pow, &max_pow);
    3561          196 :     vData = const_vec(degF, NULL);
    3562              : 
    3563        16982 :     for (i=1; i<=n_f; i++) /* prescan. set Teichmuller */
    3564              :     {
    3565        16863 :       GEN H1 = gel(vH1, i);
    3566        16863 :       long d_K = _get_d(H1), f_K = _get_f(H1), g_K = _get_g(H1);
    3567              : 
    3568        16863 :       if (f_K == d_K+1 && equaliu(p, f_K)) /* found K=Q(zeta_p) */
    3569              :       {
    3570              :         pari_timer ti;
    3571           77 :         GEN pnmax = powiu(p, max_pow), vNewton, C, MinPol;
    3572           77 :         long d_chi = 1, n_conj = eulerphiu(d_K);
    3573           77 :         ulong pmodd = umodiu(p, d_K);
    3574              : 
    3575           77 :         C = set_C(pmodd, d_K, d_chi, n_conj);
    3576           77 :         MinPol = set_minpol_teich(g_K, p, max_pow);
    3577           77 :         if (DEBUGLEVEL>3) timer_start(&ti);
    3578           77 :         vNewton = FpX_Newton(MinPol, d_K+1, pnmax);
    3579           77 :         if (DEBUGLEVEL>3)
    3580            0 :           timer_printf(&ti, "FpX_Newton: teich: %ld %ld", degpol(MinPol), d_K);
    3581           77 :         gel(vData, d_K) = mkvec4(MinPol, vNewton, C,
    3582              :                                  mkvecsmall2(d_chi, n_conj));
    3583           77 :         break;
    3584              :       }
    3585              :     }
    3586              : 
    3587        20440 :     for (i=1; i<=n_f; i++) /* handle all cyclic K */
    3588              :     {
    3589        20244 :       GEN H1 = gel(vH1, i), K, z1, Chi;
    3590        20244 :       long d_K = _get_d(H1), s_K = _get_s(H1);
    3591              :       pari_sp av2;
    3592              : 
    3593        20244 :       if ((flag&SKIP_PROPER) && degF != d_K) continue;
    3594        20244 :       if (!gel(vData, d_K))
    3595              :       {
    3596              :         pari_timer ti;
    3597          819 :         GEN pnmax = powiu(p, max_pow), vNewton, C, MinPol;
    3598          819 :         ulong pmodd = umodiu(p, d_K);
    3599          819 :         long d_chi = order_f_x(d_K, pmodd), n_conj = eulerphiu(d_K)/d_chi;
    3600              : 
    3601          819 :         C = set_C(pmodd, d_K, d_chi, n_conj);
    3602          819 :         MinPol = set_minpol(d_K, p, max_pow, n_conj);
    3603          819 :         if (DEBUGLEVEL>3) timer_start(&ti);
    3604              :         /* vNewton[2+i] = vNewton[2+i+d_K]. We need vNewton[2+i] for
    3605              :          * 0 <= i < d_K. But vNewton[2+d_K-1] may be 0 and will be deleted.
    3606              :          * So we need vNewton[2+d_K] not to delete vNewton[2+d_K-1]. */
    3607          819 :         vNewton = FpX_Newton(MinPol, d_K+1, pnmax);
    3608          819 :         if (DEBUGLEVEL>3)
    3609            0 :           timer_printf(&ti, "FpX_Newton: %ld %ld", degpol(MinPol), d_K);
    3610          819 :         gel(vData, d_K) = mkvec4(MinPol, vNewton, C,
    3611              :                                  mkvecsmall2(d_chi, n_conj));
    3612              :       }
    3613        20244 :       av2 = avma;
    3614        20244 :       Chi = s_K? NULL: get_chi(H1);
    3615        20244 :       K = shallowconcat(mkvec2(H1, Chi), gel(vData, d_K));
    3616              : #ifdef DEBUG
    3617              :       handling(K);
    3618              : #endif
    3619        20244 :       if (s_K && !(flag&NO_PLUS_PART))
    3620        10164 :         z1 = pclgp_cyc_real(K, p, max_pow, flag);
    3621        10080 :       else if (!s_K && !(flag&NO_MINUS_PART))
    3622        10080 :         z1 = pclgp_cyc_imag(K, p, start_pow, max_pow, flag);
    3623            0 :       else { set_avma(av2); continue; }
    3624        20244 :       n_sub++; n_chi += gmael(vData, d_K, 4)[2]; /* += n_conj */
    3625        20244 :       if (lg(z1) == 1) set_avma(av2);
    3626          658 :       else gr = gc_GEN(av2, shallowconcat(gr, z1));
    3627              :     }
    3628          196 :     zi = mkcol(p);
    3629          196 :     zi = vec_append(zi, (flag&NO_PLUS_PART)?nullvec():gather_part(gr, 0));
    3630          196 :     zi = vec_append(zi, (flag&NO_MINUS_PART)?nullvec():gather_part(gr, 1));
    3631          196 :     zi = shallowconcat(zi, mkcol3(cycGH, utoi(n_sub), utoi(n_chi)));
    3632          196 :     gel(z, ip) = gc_GEN(av, zi);
    3633              :   }
    3634          161 :   return typ(p0) == t_INT? shallowtrans(gel(z,1)): shallowtrans(z);
    3635              : }
    3636              : 
    3637              : static GEN
    3638          413 : reduce_gcd(GEN x1, GEN x2)
    3639              : {
    3640          413 :   GEN d = gcdii(x1, x2);
    3641          413 :   x1 = diviiexact(x1, d);
    3642          413 :   x2 = diviiexact(x2, d);
    3643          413 :   return mkvec2(x1, x2);
    3644              : }
    3645              : 
    3646              : /* norm of x0 (= pol of zeta_d with deg <= d-1) by g of order n
    3647              :  * x0^{1+g+g^2+...+g^(n-1)} */
    3648              : static GEN
    3649           49 : ber_norm_cyc(GEN x0, long g, long n, long d)
    3650              : {
    3651           49 :   pari_sp av = avma;
    3652           49 :   long i, ei, di, fi = 0, l = ulogint(n, 2);
    3653           49 :   GEN xi = x0;
    3654           49 :   ei = 1L << l; di = n / ei;
    3655          203 :   for (i = 1; i <= l; i++)
    3656              :   {
    3657          154 :     if (odd(di)) fi += ei;
    3658          154 :     ei = 1L << (l-i); di = n / ei;
    3659          154 :     xi = ZX_mod_Xnm1(ZX_mul(xi, ber_conj(xi, Fl_powu(g, ei, d), d)), d);
    3660          154 :     if (odd(di))
    3661           42 :       xi = ZX_mod_Xnm1(ZX_mul(xi, ber_conj(x0, Fl_powu(g, fi, d), d)), d);
    3662              :   }
    3663           49 :   return gc_GEN(av, xi);
    3664              : }
    3665              : 
    3666              : /* x0 a ZX of deg < d */
    3667              : static GEN
    3668           21 : ber_norm_by_cyc(GEN x0, long d, GEN MinPol)
    3669              : {
    3670           21 :   pari_sp av=avma;
    3671           21 :   GEN x = x0, z = znstar(utoi(d)), cyc = gel(z, 2), gen = gel(z, 3);
    3672           21 :   long i, l = lg(cyc);
    3673              :   pari_timer ti;
    3674              : 
    3675           21 :   if (DEBUGLEVEL>1) timer_start(&ti);
    3676           70 :   for (i = 1; i < l; i++)
    3677           49 :     x = ber_norm_cyc(x, itou(gmael(gen, i, 2)), itou(gel(cyc, i)), d);
    3678           21 :   if (DEBUGLEVEL>1) timer_printf(&ti, "ber_norm_by_cyc [ber_norm_cyc]");
    3679           21 :   x = ZX_rem(x, MinPol);  /* slow */
    3680           21 :   if (DEBUGLEVEL>1) timer_printf(&ti, "ber_norm_by_cyc [ZX_rem]");
    3681           21 :   if (lg(x) != 3) pari_err_BUG("subcyclohminus [norm of Bernoulli number]");
    3682           21 :   return gc_GEN(av, gel(x, 2));
    3683              : }
    3684              : 
    3685              : /* MinPol = polcyclo(d_K, 0).
    3686              :  * MinPol = fac*cofac (mod p).
    3687              :  * B is zv.
    3688              :  * K : H1, MinPol, [fac, cofac], C, [d_chi, n_conj] */
    3689              : static long
    3690           98 : ber_norm_by_val(GEN K, GEN B, GEN p)
    3691              : {
    3692           98 :   pari_sp av = avma;
    3693           98 :   GEN MinPol = gel(K, 2), C = gel(K, 4);
    3694           98 :   GEN vfac = gel(K, 3), fac = gel(vfac, 1), cofac = gel(vfac, 2);
    3695           98 :   long d_chi = K_get_dchi(K), n_conj = K_get_nconj(K), d_K = K_get_d(K);
    3696           98 :   long i, r, n_done = 0, x = 0, dcofac = degpol(cofac);
    3697              :   GEN pr, Done;
    3698              : 
    3699           98 :   Done = const_vecsmall(n_conj, 0);
    3700           98 :   if (lgefint(p)==3)
    3701              :   { /* mark trivial chi-part by pre-calculation */
    3702           98 :     ulong up = itou(p);
    3703           98 :     GEN facs = ZX_to_Flx(fac, up);
    3704          196 :     for (i = 1; i <= n_conj; i++)
    3705              :     {
    3706           98 :       pari_sp av2 = avma;
    3707           98 :       GEN B_conj = Flx_rem(Flx_ber_conj(B, C[i], d_K, up), facs, up);
    3708           98 :       long degB = degpol(B_conj);
    3709           98 :       set_avma(av2); if (degB < 0) continue;
    3710            0 :       Done[i] = 1; if (++n_done == n_conj) return gc_long(av, x);
    3711              :     }
    3712              :   }
    3713              :   else
    3714              :   {
    3715            0 :     for (i = 1; i <= n_conj; i++)
    3716              :     {
    3717            0 :       pari_sp av2 = avma;
    3718            0 :       GEN B_conj = FpX_rem(FpX_ber_conj(B, C[i], d_K, p), fac, p);
    3719            0 :       long degB = degpol(B_conj);
    3720            0 :       set_avma(av2); if (degB < 0) continue;
    3721            0 :       Done[i] = 1; if (++n_done == n_conj) return gc_long(av, x);
    3722              :     }
    3723              :   }
    3724          252 :   for (pr = p, r = 2; r; r <<= 1)
    3725              :   {
    3726              :     GEN polr;
    3727          252 :     pr = sqri(pr); /* p^r */
    3728          252 :     polr = (dcofac==0)? FpX_red(MinPol, pr)
    3729          252 :                       : gel(ZpX_liftfact(MinPol, vfac, pr, p, r), 1);
    3730          406 :     for (i = 1; i <= n_conj; i++)
    3731              :     {
    3732          252 :       pari_sp av2 = avma;
    3733              :       GEN B_conj;
    3734              :       long degB;
    3735          252 :       if (Done[i]) continue;
    3736          252 :       B_conj = FpX_rem(FpX_ber_conj(B, C[i], d_K, pr), polr, pr);
    3737          252 :       degB = degpol(B_conj);
    3738          252 :       set_avma(av2); if (degB < 0) continue;
    3739           98 :       x += d_chi * ZX_pval(B_conj, p);
    3740           98 :       Done[i] = 1; if (++n_done == n_conj) return gc_long(av, x);
    3741              :     }
    3742              :   }
    3743              :   pari_err_BUG("ber_norm_by_val"); return 0;/*LCOV_EXCL_LINE*/
    3744              : }
    3745              : 
    3746              : /* n > 2, p = odd prime not dividing n, e > 0, pe = p^e; d = n*p^e
    3747              :  * return generators of the subgroup H of (Z/dZ)^* corresponding to
    3748              :  * Q(zeta_{p^e}): H = {1<=a<=d | gcd(a,n)=1, a=1(mod p^e)} */
    3749              : static GEN
    3750            0 : znstar_subgr(ulong n, ulong pe, ulong d)
    3751              : {
    3752            0 :   GEN z = znstar(utoi(n)), g = gel(z, 3), G;
    3753            0 :   long i, l = lg(g);
    3754            0 :   G = cgetg(l, t_VECSMALL);
    3755            0 :   for (i=1; i<l; i++) G[i] = u_chinese_coprime(itou(gmael(g,i,2)), 1, n, pe, d);
    3756            0 :   return mkvec2(gel(z,2), G);
    3757              : }
    3758              : 
    3759              : /* K is a cyclic extension of degree n*p^e (n>=4 is even).
    3760              :  * x a ZX of deg < n*p^e. */
    3761              : static long
    3762            0 : ber_norm_with_val(GEN x, long n, ulong p, ulong e)
    3763              : {
    3764            0 :   pari_sp av = avma;
    3765            0 :   long i, j, r, degx, pe = upowuu(p, e), d = n*pe;
    3766            0 :   GEN z, gr, gen, y = cgetg(pe+2, t_POL), MinPol = polcyclo(n, 0);
    3767            0 :   y[1] = evalsigne(1) | evalvarn(0);
    3768            0 :   z = znstar_subgr(n, pe, d);
    3769            0 :   gr = gel(z, 1); gen = gel(z, 2); r = lg(gr)-1;
    3770            0 :   for (i=1; i<=r; i++)
    3771            0 :     x = ber_norm_cyc(x, itou(gel(gen, i)), itou(gel(gr, i)), d);
    3772            0 :   degx = degpol(x);
    3773            0 :   for (j=0; j<pe; j++)
    3774              :   {
    3775            0 :     GEN t = pol_zero(n), z;
    3776            0 :     long a = j; /* a=i*pe+j */
    3777            0 :     for (i=0; i<n; i++)
    3778              :     {
    3779            0 :       if (a>degx) break;
    3780            0 :       gel(t, 2+a%n) = gel(x, 2+a);
    3781            0 :       a += pe;
    3782              :     }
    3783            0 :     z = ZX_rem(ZX_renormalize(t, 2+n), MinPol);
    3784            0 :     if (degpol(z)<0) gel(y, 2+j) = gen_0;
    3785            0 :     else if (degpol(z)==0) gel(y, 2+j) = gel(z, 2);
    3786            0 :     else pari_err_BUG("ber_norm_subgr");
    3787              :   }
    3788            0 :   y = ZX_renormalize(y, pe+2);
    3789            0 :   if (e>1) y = ZX_rem(y, polcyclo(pe, 0));
    3790            0 :   return gc_long(av,  ZX_p_val(y, p, e));
    3791              : }
    3792              : 
    3793              : /* K is a cyclic extension of degree 2*p^e. x a ZX of deg < 2*p^e. In most
    3794              :  * cases, deg(x)=2*p^e-1. But deg(x) can be any value in [0, 2*p^e-1]. */
    3795              : static long
    3796          301 : ber_norm_with_val2(GEN x, ulong p, ulong e)
    3797              : {
    3798          301 :   pari_sp av = avma;
    3799          301 :   long i, d = degpol(x), pe = upowuu(p, e);
    3800          301 :   GEN y = pol_zero(pe);
    3801          301 :   if (d == 2*pe-1)
    3802              :   {
    3803        38416 :     for (i = 0; i < pe; i++)
    3804        76230 :       gel(y, 2+i) = odd(i)? subii(gel(x, 2+i+pe), gel(x, 2+i))
    3805        38115 :                           : subii(gel(x, 2+i), gel(x, 2+i+pe));
    3806              :   }
    3807              :   else
    3808              :   {
    3809            0 :     for (i = 0; i < pe && i <= d; i++)
    3810            0 :       gel(y, 2+i) = odd(i)? negi(gel(x, 2+i)): gel(x, 2+i);
    3811            0 :     for (i = pe; i <= d; i++)
    3812            0 :       gel(y, 2+i-pe) = odd(i)? subii(gel(y, 2+i-pe), gel(x, 2+i))
    3813            0 :                              : addii(gel(y, 2+i-pe), gel(x, 2+i));
    3814              :   }
    3815          301 :   y = ZX_renormalize(y, 2+pe);
    3816          301 :   if (e > 1) y = ZX_rem(y, polcyclo(pe, 0));
    3817          301 :   return gc_long(av, ZX_p_val(y, p, e));
    3818              : }
    3819              : 
    3820              : /* K : H1, MinPol, [fac, cofac], C, [d_chi, n_conj] */
    3821              : static GEN
    3822          812 : ber_cyc5(GEN K, GEN p)
    3823              : {
    3824          812 :   pari_sp av = avma;
    3825          812 :   GEN MinPol = gel(K, 2), H = K_get_H(K);
    3826          812 :   long d = K_get_d(K), f = K_get_f(K), h = K_get_h(K), g = K_get_g(K);
    3827          812 :   GEN x, x1, x2, y, B = const_vecsmall(d+1, 0);
    3828          812 :   long i, j, gi, e, f2 = f>>1, dMinPol = degpol(MinPol), chi2 = -1, *B2 = B+2;
    3829              : 
    3830              :   /* get_chi inlined here to save memory */
    3831     18111989 :   for (j=1; j<=h; j++) /* i = 0 */
    3832              :   {
    3833     18111177 :     if (H[j] == 2) chi2 = 0;
    3834     18111177 :     if (H[j] <= f2) B2[0]++; /* Chi[H[j]] = 0 */
    3835              :   }
    3836        97314 :   for (i = 1, gi = g; i < d; i++)
    3837              :   {
    3838     93017085 :     for (j=1; j<=h; j++)
    3839              :     {
    3840     92920583 :       long t = Fl_mul(gi, H[j], f); /* Chi[t] = i */
    3841     92920583 :       if (t == 2) chi2 = i;
    3842     92920583 :       if (t <= f2) B2[i]++;
    3843              :     }
    3844        96502 :     gi = Fl_mul(gi, g, f);
    3845              :   }
    3846          812 :   y = zx_to_ZX(zx_renormalize(B, d+2));
    3847              : 
    3848          812 :   if (p)
    3849              :   {
    3850              :     ulong n;
    3851          399 :     e = u_pvalrem(d, p, &n);
    3852          399 :     if (e == 0)
    3853           98 :       x1 = utoi(ber_norm_by_val(K, B, p));
    3854          301 :     else if (n > 2)
    3855            0 :       x1 = utoi(ber_norm_with_val(y, n, itou(p), e));
    3856              :     else
    3857          301 :       x1 = utoi(ber_norm_with_val2(y, itou(p), e));
    3858              :   }
    3859              :   else
    3860              :   {
    3861          413 :     if (dMinPol > 100)
    3862           21 :       x1 = ber_norm_by_cyc(y, d, MinPol);
    3863              :     else
    3864          392 :       x1 = ZX_resultant(MinPol, ZX_rem(y, MinPol));
    3865              :   }
    3866              : 
    3867          812 :   if (chi2 < 0) /* chi2 = Chi[2] */
    3868            0 :     x2 = shifti(gen_1, 2*dMinPol);
    3869          812 :   else if (chi2 == 0)
    3870           21 :     x2 = shifti(gen_1, dMinPol);
    3871              :   else
    3872              :   {
    3873          791 :     long e = d/ugcd(chi2, d);
    3874          791 :     x2 = powiu(polcyclo_eval(e, gen_2), eulerphiu(d)/eulerphiu(e));
    3875          791 :     x2 = shifti(x2, dMinPol);
    3876              :   }
    3877          812 :   if (p) x = stoi(itou(x1)-Z_pval(x2, p)); else x = reduce_gcd(x1, x2);
    3878          812 :   return gc_GEN(av, x);
    3879              : }
    3880              : 
    3881              : /*  Hirabayashi-Yoshino, Manuscripta Math. vol.60, 423-436 (1988), Theorem 1
    3882              :  *
    3883              :  *  F is a subfield of Q(zeta_f)
    3884              :  *  f=p^a => Q=1
    3885              :  *  If F=Q(zeta_f), Q=1 <=> f=p^a
    3886              :  *  If f=4*p^a, p^a*q^b (p,q are odd primes), Q=2 <=> [Q(zeta_f):F] is odd */
    3887              : static long
    3888           21 : unit_index(ulong d, ulong f)
    3889              : {
    3890              :   ulong r, d_f;
    3891           21 :   GEN fa = factoru(f), P = gel(fa, 1), E = gel(fa, 2); r = lg(P)-1;
    3892           21 :   if (r==1) return 1;  /* f=P^a */
    3893            7 :   d_f = eulerphiu_fact(fa);
    3894            7 :   if (d==d_f) return 2;  /* F=Q(zeta_f) */
    3895            0 :   if (r==2 && ((P[1]==2 && E[1]==2) || P[1]>2)) return odd(d_f/d)?2:1;
    3896            0 :   return 0;
    3897              : }
    3898              : 
    3899              : /* Compute relative class number h of the subfield K of Q(zeta_f)
    3900              :  * corresponding to the subgroup HH of (Z/fZ)^*.
    3901              :  * If p!=NULL, then return valuation(h,p). */
    3902              : static GEN
    3903          119 : rel_class_num(long f, GEN HH, long degF, GEN p)
    3904              : {
    3905              :   long i, n_f, W, Q;
    3906          119 :   GEN vH1, vData, x, z = gen_1, z1 = gen_0, z2 = mkvec2(gen_1, gen_1);
    3907              : 
    3908          119 :   vH1 = GHinit(f, HH, NULL); n_f = lg(vH1)-1;
    3909          119 :   vData = const_vec(degF, NULL);
    3910         1652 :   for (i=1; i<=n_f; i++)
    3911              :   {
    3912         1533 :     GEN H1 = gel(vH1, i), K;
    3913         1533 :     long d_K = _get_d(H1), s = _get_s(H1);
    3914              : 
    3915         1533 :     if (s) continue;  /* F is real */
    3916              : #ifdef DEBUG
    3917              :     err_printf("  handling %s cyclic subfield K, deg(K)=%ld, cond(K)=%ld\n",
    3918              :         s? "a real": "an imaginary", d_K, _get_f(H1));
    3919              : #endif
    3920          812 :     if (!gel(vData, d_K))
    3921              :     {
    3922              :       GEN C, MinPol, fac, cofac;
    3923              :       ulong d_chi, n_conj;
    3924          497 :       MinPol = polcyclo(d_K,0);
    3925          497 :       if (p && umodui(d_K, p))
    3926           98 :       {
    3927           98 :         ulong pmodd = umodiu(p, d_K);
    3928           98 :         GEN MinPol_p = FpX_red(MinPol, p);
    3929           98 :         d_chi = order_f_x(d_K, pmodd);
    3930           98 :         n_conj = eulerphiu(d_K)/d_chi;
    3931           98 :         if (n_conj==1) fac = MinPol_p;  /* polcyclo(d_K) is irred mod p */
    3932            0 :         else fac = FpX_one_cyclo(d_K, p);
    3933           98 :         cofac = FpX_div(MinPol_p, fac, p);
    3934           98 :         C = set_C(pmodd, d_K, d_chi, n_conj);
    3935              :       }
    3936              :       else
    3937              :       {
    3938          399 :         fac = cofac = C = NULL;
    3939          399 :         d_chi = n_conj = 0;
    3940              :       }
    3941          497 :       gel(vData, d_K) = mkvec5(MinPol, mkvec2(fac, cofac), C,
    3942              :                                NULL, mkvecsmall2(d_chi, n_conj));
    3943              :     }
    3944          812 :     K = vec_prepend(gel(vData, d_K), H1);
    3945          812 :     z = ber_cyc5(K, p);
    3946          812 :     if (p) z1 = addii(z1, z);
    3947              :     else
    3948              :     {
    3949          413 :       gel(z2, 1) = mulii(gel(z2, 1), gel(z, 1));
    3950          413 :       gel(z2, 2) = mulii(gel(z2, 2), gel(z, 2));
    3951              :     }
    3952              :   }
    3953          119 :   W = root_of_1(f, HH);
    3954          119 :   if (p) return addiu(z1, z_pval(W, p));
    3955           21 :   Q = unit_index(degF, f);
    3956           21 :   x = dvmdii(muliu(gel(z2,1), 2 * W), gel(z2,2), &z1);
    3957           21 :   if (signe(z1)) pari_err_BUG("subcyclohminus [norm of Bernoulli number]");
    3958           21 :   if (!Q && mpodd(x)) Q = 2; /* FIXME: can this happen ? */
    3959           21 :   if (Q == 1) x = shifti(x, -1);
    3960           21 :   return mkvec2(x, utoi(Q));
    3961              : }
    3962              : 
    3963              : static void
    3964          336 : checkp(const char *fun, long degF, GEN p)
    3965              : {
    3966          336 :   if (!BPSW_psp(p)) pari_err_PRIME(fun, p);
    3967          329 :   if (equaliu(p, 2)) pari_err_DOMAIN(fun,"p","=", gen_2, p);
    3968          315 :   if (degF && dvdsi(degF, p)) errpdiv(fun, p, degF);
    3969          301 : }
    3970              : 
    3971              : /* if flag is set, handle quadratic fields specially (don't set H) */
    3972              : static long
    3973          441 : subcyclo_init(const char *fun, GEN FH, long *pdegF, GEN *pH, long flag)
    3974              : {
    3975          441 :   long f = 0, degF = 2;
    3976          441 :   GEN F = NULL, H = NULL;
    3977          441 :   if (typ(FH) == t_POL)
    3978              :   {
    3979           77 :     degF = degpol(FH);
    3980           77 :     if (degF < 1 || !RgX_is_ZX(FH)) pari_err_TYPE(fun, FH);
    3981           77 :     if (flag && degF == 2)
    3982              :     {
    3983           56 :       F = coredisc(ZX_disc(FH));
    3984           56 :       if (is_bigint(F))
    3985            0 :         pari_err_IMPL(stack_sprintf("conductor f > %lu in %s", ULONG_MAX, fun));
    3986           56 :       f = itos(F); if (f == 1) degF = 1;
    3987              :     }
    3988              :     else
    3989              :     {
    3990           21 :       GEN z, bnf = Buchall(pol_x(fetch_var()), 0, DEFAULTPREC);
    3991           21 :       z = rnfconductor(bnf, FH); H = gel(z,3);
    3992           21 :       f = subcyclo_nH(fun, gel(z,2), &H);
    3993           21 :       delete_var();
    3994           21 :       H = znstar_generate(f, H); /* group elements */
    3995              :     }
    3996              :   }
    3997              :   else
    3998              :   {
    3999          364 :     long l = lg(FH), fH;
    4000          364 :     if (typ(FH) == t_INT) F = FH;
    4001          273 :     else if (typ(FH) == t_VEC && (l == 2 || l == 3))
    4002              :     {
    4003          273 :       F = gel(FH, 1);
    4004          273 :       if (l == 3) H = gel(FH, 2);
    4005              :     }
    4006            0 :     else pari_err_TYPE(fun, FH);
    4007          364 :     f = subcyclo_nH(fun, F, &H);
    4008          350 :     H = znstar_generate(f, H); /* group elements */
    4009          350 :     fH = znstar_conductor(H);
    4010          350 :     if (fH == 1) degF = 1;
    4011              :     else
    4012              :     {
    4013          350 :       if (fH != f) { H = znstar_reduce_modulus(H, fH); f = fH; }
    4014          350 :       degF = eulerphiu(f) / zv_prod(gel(H, 2));
    4015              :     }
    4016              :   }
    4017          427 :   *pH = H; *pdegF = degF; return f;
    4018              : }
    4019              : 
    4020              : GEN
    4021          210 : subcyclopclgp(GEN FH, GEN p, long flag)
    4022              : {
    4023          210 :   pari_sp av = avma;
    4024              :   GEN H;
    4025          210 :   long degF, f = subcyclo_init("subcyclopclgp", FH, &degF, &H, 0);
    4026          203 :   if (typ(p) == t_VEC)
    4027              :   {
    4028           28 :     long i, l = lg(p);
    4029           77 :     for (i = 1; i < l; i++) checkp("subcyclopclgp", degF, gel(p, i));
    4030           14 :     if (f == 1) { set_avma(av); return const_vec(l-1, nullvec()); }
    4031              :   }
    4032              :   else
    4033              :   {
    4034          175 :     checkp("subcyclopclgp", degF, p);
    4035          154 :     if (f == 1) { set_avma(av); return nullvec(); }
    4036              :   }
    4037          168 :   if (flag >= USE_BASIS) pari_err_FLAG("subcyclopclgp");
    4038          161 :   return gc_GEN(av, pclgp(p, f, H, degF, flag));
    4039              : }
    4040              : 
    4041              : static GEN
    4042          126 : subcycloiwasawa_i(GEN FH, GEN P, long n)
    4043              : {
    4044              :   long B, p, f, degF;
    4045              :   GEN H;
    4046          126 :   const char *fun = "subcycloiwasawa";
    4047              : 
    4048          126 :   if (typ(P) != t_INT) pari_err_TYPE(fun, P);
    4049          126 :   if (n < 0) pari_err_DOMAIN(fun, "n", "<", gen_0, stoi(n));
    4050          126 :   B = 1L << (BITS_IN_LONG/4);
    4051          126 :   if (is_bigint(P) || cmpiu(P, B) > 0)
    4052            7 :     pari_err_IMPL(stack_sprintf("prime p > %ld in %s", B, fun));
    4053          119 :   p = itos(P);
    4054          119 :   if (p <= 1 || !uisprime(p)) pari_err_PRIME(fun, P);
    4055          119 :   if (!upowuu(p, n+1))
    4056            7 :     pari_err_IMPL(stack_sprintf("p^n > 2^%ld in %s", BITS_IN_LONG, fun));
    4057          112 :   f = subcyclo_init(fun, FH, &degF, &H, 1);
    4058          105 :   if (degF == 1) return NULL;
    4059          105 :   if (degF == 2)
    4060              :   {
    4061           56 :     long m = ((f & 3) == 0)? f / 4: f;
    4062           56 :     if (H && !srh_1(H)) m = -m;
    4063           56 :     if (!n) return quadlambda(p, m);
    4064           28 :     return m < 0? imagquadstkpol(p, m, n): realquadstkpol(p, m, n);
    4065              :   }
    4066           49 :   if (p == 2) pari_err_DOMAIN(fun, "p", "=", gen_2, gen_2);
    4067           49 :   if (srh_1(H)) return NULL;
    4068           49 :   if (degF % p == 0) errpdiv("abeliwasawa", P, degF);
    4069           49 :   return abeliwasawa(p, f, H, degF, n);
    4070              : }
    4071              : GEN
    4072          126 : subcycloiwasawa(GEN FH, GEN P, long n)
    4073              : {
    4074          126 :   pari_sp av = avma;
    4075          126 :   GEN z = subcycloiwasawa_i(FH, P, n);
    4076          105 :   if (!z) { set_avma(av); return n? nullvec(): mkvec(gen_0); }
    4077          105 :   return gc_GEN(av, z);
    4078              : }
    4079              : 
    4080              : GEN
    4081          119 : subcyclohminus(GEN FH, GEN P)
    4082              : {
    4083          119 :   const char *fun = "subcyclohminus";
    4084          119 :   pari_sp av = avma;
    4085              :   GEN H;
    4086          119 :   long degF, f = subcyclo_init(fun, FH, &degF, &H, 0);
    4087          119 :   if (P)
    4088              :   {
    4089           98 :     if (typ(P) != t_INT) pari_err_TYPE(fun, P);
    4090           98 :     if (isintzero(P)) P = NULL; else checkp(fun, 0, P);
    4091              :   }
    4092          119 :   if (degF == 1 ||  srh_1(H) == 1) return gen_1;
    4093          119 :   return gc_GEN(av, rel_class_num(f, H, degF, P));
    4094              : }
        

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