Re: Problem with Flx_ffisom function

[Karim Belabas <Karim.Belabas@math.u-bordeaux.fr>]

Hi,

* Jean-Pierre Flori [2014-12-05 17:03]:
> The following programs errors out claiming that the produced
> irreducible polynomial is not anymore
> (***   not an irreducible polynomial in FpX_ffintersect):
> 
> #include <stdlib.h>
> #include <stdio.h>
> #include <time.h>
> 
> #include <pari/pari.h>
> 
> int main (int argc, char **argv)
> {
>         int i;
>         unsigned long l;
>         long n, v;
>         GEN p, f, r;
> 
>         pari_init(1<<30, 1UL<<20);
> 
>         v = 0L;
> 
>         l = unextprime(1UL<<20);
>         p = stoi(l);
>         n = 179L;
>         f = init_Fq(p, n, v);
>         i = Flx_is_irred(ZX_to_Flx(f, l), l);
                           ^^^^^^^^^^^^^^^
>         pari_printf("%d\n", i);
> 
>         t = clock();
          ^^^^^^^^^^^^  [ I'd declare t ... ]
> /*
>         The following works fine.
> */
>         r = FpX_ffisom(f, f, p);
>         pari_printf("%Ps\n", r);
> /*
>         This errors out
> */
>         r = Flx_ffisom(f, f, l);

I'd apply Flx_ffisom to a Flx, as correctly done above.
Not to the original FpX.

After

  f = ZX_to_Flx(f,l)

(and declaring clock_t t) the code above works fine.

> Thanks in advance for the support!

You're welcome :-)

    K.B.
--
Karim Belabas, IMB (UMR 5251)  Tel: (+33) (0)5 40 00 26 17
Universite de Bordeaux         Fax: (+33) (0)5 40 00 69 50
351, cours de la Liberation    http://www.math.u-bordeaux1.fr/~kbelabas/
F-33405 Talence (France)       http://pari.math.u-bordeaux1.fr/  [PARI/GP]
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