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21093RE: [PrimeNumbers] Prp vs. pfgw.

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  • mgrogue@wi.rr.com
    Nov 9, 2009
      ---- Chris Caldwell <caldwell@...> wrote:
      > > I must test numbers in the form k*2^n+1.
      > > Is Pfgw faster than prp.exe?
      > Others will correct me if I am wrong, but I think they use the same
      > arithmetic engine now. Of course prp.exe does not prove primality. LLR
      > might be the fastest depending on k, but the key thing to do is to
      > prescreen well--that is where you can save a great deal of time.

      For base 2, I recommend LLR, since it will automatically do a Proth test for k*2^n+1 numbers. You could also use PFGW, but you would need to force a primality test by using the -tm option. The problem with PFGW is that it will not produce a residue for primality tests. LLR produces a residue for all tests. LLR should be just as fast as PFGW for this base.

      I suspect that George is keeping PRP up to date with his changes to gwnum, but I think he has slowly been moving those functions to Prime95. As Chris said, PRP cannot do a primality test.

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