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Prp vs. pfgw.

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  • Di Maria Giovanni
    Hi I must test numbers in the form k*2^n+1. Is Pfgw faster than prp.exe? Thank Giovanni Di Maria
    Message 1 of 3 , Nov 8, 2009
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      Hi
      I must test numbers in the form k*2^n+1.
      Is Pfgw faster than prp.exe?
      Thank
      Giovanni Di Maria
    • Chris Caldwell
      ... 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
      Message 2 of 3 , Nov 8, 2009
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        > 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.
      • mgrogue@wi.rr.com
        ... 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
        Message 3 of 3 , Nov 9, 2009
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          ---- 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.

          --Mark
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