Mercurial > jwe > octave
diff libinterp/corefcn/__isprimelarge__.cc @ 31055:3a93a77dd4cf stable
Minor performance tweaks to isprime.m and __isprimelarge__.cc
__isprimelarge__.cc: change an if-else ladder to a single equivalent
return statement, about 1% faster and less code.
isprime.m: periodic check and retune of internal threshold parameter
used to select one technique over the other.
| author | Arun Giridhar <arungiridhar@gmail.com> |
|---|---|
| date | Wed, 01 Jun 2022 17:19:30 -0400 |
| parents | cfade47fc4fc |
| children | 5f015f2829b7 |
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--- a/libinterp/corefcn/__isprimelarge__.cc Tue May 31 23:30:40 2022 -0400 +++ b/libinterp/corefcn/__isprimelarge__.cc Wed Jun 01 17:19:30 2022 -0400 @@ -115,20 +115,12 @@ // If the number passes all 12 tests, then it is prime. // If it fails any, then it is composite. // The first 12 primes suffice to test all 64-bit integers. - if (! millerrabin ( 2, d, r, n)) return false; - if (! millerrabin ( 3, d, r, n)) return false; - if (! millerrabin ( 5, d, r, n)) return false; - if (! millerrabin ( 7, d, r, n)) return false; - if (! millerrabin (11, d, r, n)) return false; - if (! millerrabin (13, d, r, n)) return false; - if (! millerrabin (17, d, r, n)) return false; - if (! millerrabin (19, d, r, n)) return false; - if (! millerrabin (23, d, r, n)) return false; - if (! millerrabin (29, d, r, n)) return false; - if (! millerrabin (31, d, r, n)) return false; - if (! millerrabin (37, d, r, n)) return false; - // If we are all the way here, then it is prime. - return true; + return millerrabin ( 2, d, r, n) && millerrabin ( 3, d, r, n) + && millerrabin ( 5, d, r, n) && millerrabin ( 7, d, r, n) + && millerrabin (11, d, r, n) && millerrabin (13, d, r, n) + && millerrabin (17, d, r, n) && millerrabin (19, d, r, n) + && millerrabin (23, d, r, n) && millerrabin (29, d, r, n) + && millerrabin (31, d, r, n) && millerrabin (37, d, r, n); /* Mathematical references for the curious as to why we need only