Karim Belabas on Fri, 30 Dec 2016 11:32:04 +0100 |
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Re: Getting a very large polynomial into pari/gp |
* Neill Clift [2016-12-30 06:17]: > Hi, > I want to do a gcd with two polynomials with 16 million coefficients mod > a large 64 bit prime. > Playing with gp with some sparse polynomials it looks like it can do the > calculation. > If I try to read in a dense polynomial of large size though gp overflows > its stack (runs out of thread stack space, not a buffer overflow or gp > stack). > I assume your parser is putting a lot of data on the thread stack. > I am using a command like this: > > gp > a = read("a.gp") > > I am doing this on windows. > Is there some kind of raw read or similar that will let me get a large > polynomial into gp? I can put the data into different formats rather > than the symbolic format I am trying currently. 1) The most natural way would be to just (re)create the polynomials inside gp. 2) If this is not possible, you can try a vector of coefficients. Then a = read("a.gp"); A = Pol(a); \\ leading coeff in a[1], etc. Cheers, K.B. -- Karim Belabas, IMB (UMR 5251) Tel: (+33) (0)5 40 00 26 17 Universite de Bordeaux Fax: (+33) (0)5 40 00 21 23 351, cours de la Liberation http://www.math.u-bordeaux.fr/~kbelabas/ F-33405 Talence (France) http://pari.math.u-bordeaux.fr/ [PARI/GP] `