Neill Clift on Sun, 01 Jan 2017 04:47:21 +0100 |
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Re: Getting a very large polynomial into pari/gp |
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' Thanks. Neill.