Re: Good GMP performance (WAS Re: Problems linking with gmp...)

[Will Galway]

Torbjorn Granlund writes:
 > Will Galway <address@hidden> writes:
 > 
 >   At some later date I'll probably send out a note asking for advice on
 >   getting a higher-performance modular exponentiation routine, in the
 >   hopes that I can do better than mpz_powm (which is what I'm using
 >   now).  The speed at which I can do modular exponentiations is the
 >   limiting factor in a computation I'm currently working on (searching
 >   for pseudoprimes).  I'm hoping that I can do significantly better than
 >   mpz_powm because for this application my needs are limited to
 >   computing 2^k modulo n, where both k and n are (unsigned) 64-bit
 >   integers.  Using mpz_powm, it looks like I'm getting roughly 10^5
 >   modular exponentiations per second on a 1.2 GHz Athlon....
 >   
 > Hack something in low-level C with umul_ppmm fro longlong.h.
 > Don't bother with the rest of GMP.
 > 
 > -- 
 > Torbjörn

OK, thanks -- I'll have a look at longlong.h.

--Will
( mailto:address@hidden http://www.cecm.sfu.ca/~wfgalway )