Would someone mind elaborating the explanation in the manual?
Sisyphus
kalinabears at iinet.net.au
Sun Oct 26 10:13:10 CET 2003
Brian Hurt wrote:
>
> This is a speed up because compared to doing a long mod long, doing a
> mpz_t mod long is expensive. The above code is almost 3x as fast as the
> naive implementation:
>
> int foo(mpz_t x) {
> if ((mpz_fdiv_ui(x, 23ul) == 0ul) || (mpz_fdiv_ui(x, 29ul) == 0ul)
> || (mpz_fdiv_ui(x, 31ul) == 0ul))
> {
> return 1;
> } else {
> return 0;
> }
> }
>
But if you wanted to see if x was divisible by either 23, 29, or 32 I
think you would use mpz_divisible_ui() instead ?
I don't know how the speeds compare in that case.
Cheers,
Rob
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