mpz_prevprime #10
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mpz_prevprime #10
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sethtroisi
commented
Aug 21, 2019
| for (i = 0; i < prime_limit; i++) | ||
| { | ||
| unsigned r; | ||
| /* FIXME: Reduce moduli + incr and store back, to allow for |
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I tested several versions of this and none of them were faster.
sethtroisi
commented
Aug 21, 2019
| @@ -82,47 +122,54 @@ mpz_nextprime (mpz_ptr p, mpz_srcptr n) | |||
| /* Compute residues modulo small odd primes */ | |||
| moduli = TMP_SALLOC_TYPE (prime_limit * sizeof moduli[0], unsigned short); | |||
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| for (;;) | |||
| { | |||
| /* FIXME: Compute lazily? */ | |||
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I tried this too and it's not useful, because to exit the lower loop you have to check each of these is non-zero, so there all need to be calculated, and reordering doesn't seem to help (as there is overhead in tracking if they are calculated)
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A different version (much better) is close to being merged upstream. |
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mpz_prevprime