Thread: YAFU-1.34
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Old 2013-02-25, 15:57   #1
bsquared's Avatar
Feb 2007

22·3·293 Posts
Default YAFU-1.34

There is a lot of new stuff in this version, highlights include:

Fully automated SNFS factorization. Polynomial selection is supported for a variety of special forms:
N = a*b^n +/- c, for b < 100, c < 2^30, N < 1024 bits
N = b^n +/- 1, for b > 100, N < 1024 bits
N = a^n +/- b^n, for gcd(a,b) = 1, a,b <= 12, N < 1024 bits
N = x^y + y^x, for 1 < x < y < 151, N < 1024 bits

There are two ways to run it. "nfs(number)" will autodetect any of the above forms, and proceed with the primitive factor of the input - but only in "pure" form (i.e., the number can't have been reduced by any known large factors). Use "snfs(number, cofactor)", where "number" is the pure form (i.e. 2^1039-1) and "cofactor" is the number reduced by any known large factors.

Next, WraithX contributed his port of APRCL to YAFU, so now every factor found will be automatically proved prime. A couple new options control when it is run and how verbose the output is: -aprcl_p <num> and -aprcl_d <num>. The defaults are: below 500 digits are automatically proved (the upper end of that range can take a minute or two) and above 200 digits extra verbosity is enabled.

1.34 also contains the first real speedup of my SIQS code in a while. New SSE2 code gives a 2-3% speedup, or, on supported systems, SSE4.1 code gives about a 10% speedup. SSE4.1 is automatically detected and used if found.

Finally, there are quite a few bugfixes and minor updates. Check the changelog for details.

May thanks to all bug reporters and developers that contributed to this version! Very much appreciated!

Happy factoring,
- ben.

Last fiddled with by bsquared on 2013-02-25 at 15:59 Reason: add link
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