Bill Allombert on Sun, 24 May 2015 17:37:36 +0200 |
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Re: keep flag=1 recursively in isprime |
On Tue, May 05, 2015 at 10:53:11PM +0200, Pascal Molin wrote: > isprime(p,1) calls Pocklington-Lehmer only at the first recursion level and > then > falls back to the check_prime rountine which may call APRCL. > > Looking at the code I assume this is intentional but I find it misleading. > I would prefer if the flag were kept recursively, or suggest having a > stronger flag ensuring to use only the PL test -- in particular the > returned certificate would never contain '2'. This is not really practical. However, what should be done is for check_prime to use the same criterion as BPSW_isprime_big, instead of simply (expi(p) <= 250), otherwise * 2 if x is a large prime whose primality could only sensibly be proven (given the algorithms implemented in PARI) using the APRCL test. is a white lie. Cheers, Bill.