Bill Allombert on Sun, 06 May 2012 20:18:09 +0200

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Re: nextprime or isprime - which is faster

On Sun, May 06, 2012 at 02:54:09AM -0700, zak seidov wrote:
> i run (elementary) pari for 12-13 digit numbers looking for some primes,
> and wonder which command is faster nextprime or isprime.

nextprime only check for pseudoprimality (like ispseudoprime) so is faster than
isprime for large primes.

> I use: 
> Reading GPRC: /cygdrive/c/Program Files/PARI/.gprc ...Done.
>                   GP/PARI CALCULATOR Version 2.3.4 (released)
>            i686 running cygwin (ix86/GMP-4.2.1 kernel) 32-bit version
>  compiled: Jul 12 2008, gcc-3.4.4 (cygming special, gdc 0.12, using dmd 0.125)
>                 (readline v5.2 enabled, extended help available)
>                      Copyright (C) 2000-2006 The PARI Group

Please try to upgrade to PARI 2.5.1.

> btw is "extended help available", i guess not

This is a known problem with the PARI 2.3 installer on Vista/win7