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Re: [PrimeNumbers] building factoring routines

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  • Jud McCranie
    ... For numbers in that range (fewer than 64 bits), I wouldn t use HIT or any other such package. Just use the native data types. Also, Shank s method is
    Message 1 of 4 , Jun 3, 2006
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      At 09:42 AM 6/3/2006, hecht wrote:
      >I can factor numbers in the 12 digit range pretty quickly now, but it still
      >took over a minute to find a factor of 10^15 + 3.
      >
      >Why so long? It takes me 24 ms (Pollard Rho, HIT library, PIII 700 MHz)

      For numbers in that range (fewer than 64 bits), I wouldn't use HIT or any
      other such package. Just use the native data types. Also, Shank's method
      is probably better for that application than Pollard's method. My program
      on a 2.4 GHz factors 10^15+3 in 0.01 second.
    • Phil Carmody
      ... Now I ve decomissioned my PPro/200, I don t have a machine slow enough to measure my native double reimplimantation of Lenstra s (LIP) version of Shanks
      Message 2 of 4 , Jun 3, 2006
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        --- Jud McCranie <j.mccranie@...> wrote:
        > At 09:42 AM 6/3/2006, hecht wrote:
        > >I can factor numbers in the 12 digit range pretty quickly now, but it still
        > >took over a minute to find a factor of 10^15 + 3.
        > >
        > >Why so long? It takes me 24 ms (Pollard Rho, HIT library, PIII 700 MHz)
        >
        > For numbers in that range (fewer than 64 bits), I wouldn't use HIT or any
        > other such package. Just use the native data types. Also, Shank's method
        > is probably better for that application than Pollard's method. My program
        > on a 2.4 GHz factors 10^15+3 in 0.01 second.

        Now I've decomissioned my PPro/200, I don't have a machine slow
        enough to measure my native double reimplimantation of Lenstra's
        (LIP) version of Shanks' SQUFOF on that number! (And I gave away
        my ARM dev board yesterday - that would have been really slow.)

        However, I found two Sparcs, with their notoriously underpowered FPUs,
        in America, and indeed they are slow enough for it to be measurable:
        SunBlade100 - 0.007s
        SunUltra5 - 0.010s
        (no idea what clock speed they may be).

        Paul - may I post the code? It's Lenstra's copyright, but you seem
        to be the guardian of it presently?

        Phil

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