GNU bug report logs - #12350
Composites identified as primes in factor.c (when HAVE_GMP)

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From: Torbjorn Granlund <tg <at> gmplib.org>
To: Pádraig Brady <P <at> draigBrady.com>
Cc: 12350 <at> debbugs.gnu.org, nisse <at> lysator.liu.se, Jim Meyering <jim <at> meyering.net>
Subject: bug#12350: Composites identified as primes in factor.c (when HAVE_GMP)
Date: Tue, 04 Sep 2012 23:55:58 +0200

Pádraig Brady <P <at> draigBrady.com> writes:

  Sure. I was just quantifying the performance change,
  for others who may be referencing or noticing patches.
  (Actually, I'd add a note to the commit message that,
  this increases calculations by about 25%).
  
And surely mode for certain cases. We spend 25/3 or about 8 times more
effort in Miller Rabin.

  > As I mentioned in the original post, we will replace the current code
  > with code that is many times faster.  Your example above will run at
  > less than a minute on your system.
  
  I'd left my test files in place in anticipation ;)
  
Please do, and let me and Niels know if it takes more than 45s.  Your
test case takes 28s on my 3.3 GHz Sandy bridge system with our current
code.  I'm a little disappointed the code doesn't beat the old code more
for small factorisations.

-- 
Torbjörn

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