Bill Allombert on Sun, 01 Jan 2017 18:39:07 +0100 |
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Re: Getting a very large polynomial into pari/gp |
On Sun, Jan 01, 2017 at 03:47:11AM +0000, Neill Clift wrote: > On 12/31/2016 9:05 AM, Bill Allombert wrote: > > The libpari library provides a set of functions to deal with polynomials > > over F_p that implement the half-GCD algorithm but they are not directly > > available in GP. > > > > Try: > > install("FpX_gcd","GGG") > > p = 2^64-59; > > a = Pol(read("a.gp")); > > b = Pol(read("b.gp")); > > FpX_gcd(a,b,p) > > > > and actually since p is less than 2^64 there is another function that > > use a more compact representation of polynomials (Vecsmall), but the > > above function will do the conversions for you. > > Read about FpX, FpX_gcd, Flx and Flx_gcd in the documentation. > While the other gcd ran overnight this one failed in an hour. > > (18:03) gp > FpX_gcd(a,b,p) > *** at top-level: FpX_gcd(a,b,p) > *** ^-------------- > *** FpX_gcd: not enough memory > (19:08) gp > > > This seems to be different from the stack size messages I have got > (stack size set to 64G). > > If you use Windows make sure to use the installer and ot the stand-alone > > binary. Unfortunately install() does not work with the stand-alone > > binary. > I believe I used the installer as I have a desktop icon that's a > shortcut to pari/gp and it shows installed in control panel. > > > > For this kind of computation, you should consider using the PARI library > > directly. > That was my initial thought as well but my first try at getting the code > to compile with just the Pari header included gave me errors: > > 1>../src/kernel/none/divll_pre.h(37): error C2275: 'pari_ulong': illegal > use of this type as an expression > 1> c:\program files (x86)\pari64-2-9-1\include\pari\parigen.h(17): > note: see declaration of 'pari_ulong' > 1>../src/kernel/none/divll_pre.h(37): error C2146: syntax error: missing > ')' before identifier '__arg' You should try this on Linux with gcc. On win64, only mingw64 is supported and even this is haskish, see config/convertllp64 in the PARi distribution. Cheers, Bill.