20141027, 18:06  #320  
"Ben"
Feb 2007
3,371 Posts 
Quote:
So, I rebuilt MPIR 2.6.0, gmpecm 6.4.4, and then yafu, after which everything appears to work on windows (Msys). This one runs fine (yafu ultimately picks GNFS), the previous one picked a poly and started test sieving, and this bug is also fixed. 

20141027, 20:18  #321 
Jun 2012
B90_{16} Posts 
Great news! I will rerun the bug cases on my machines, though I'm traveling this week so it may be a few days until I get to it.
Thanks for all the work. 
20141027, 20:42  #322 
"Ben"
Feb 2007
3,371 Posts 
Ok, but just to be clear, I haven't changed anything in either SVN or the downloadable executable... so you would have to rebuild everything yourself to see things fixed.

20141027, 21:25  #323 
Jun 2012
2^{4}×5×37 Posts 
Ok  I (wrongly) assumed souceforge had been updated with all the executables. I can't compile on Windows. Will just have to wait for it to be compiled/tested/released formally.
But you found the underlying problem, which is very cool. 
20141113, 16:57  #324 
Apr 2014
Marlow, UK
2^{3}×7 Posts 
YAFU rho() performance 'bug'?
Hi Ben,
Pollard Rho probably isn't of much interest, but in case it is: I just spotted what appears to be a typo in rho.c around line 195: Code:
for(i=0;i<=r;i++) { mpz_mul(t1,y,y); //y = (y*y + c) mod n mpz_add_ui(t1, t1, c); mpz_tdiv_r(t1, t1, fobj>rho_obj.gmp_n); } Code:
mpz_tdiv_r(y, t1, fobj>rho_obj.gmp_n); Also, I think the loop should start at i=1 rather than i=0 (or have < rather than <=), though I could be wrong... Cheers, Mick. 
20141124, 21:09  #325 
Apr 2012
2×47 Posts 
it would be great if somebody could upload a compiled Windows x64 binary with the latest corrected code, please.

20141205, 07:49  #326 
Feb 2013
2×229 Posts 
Apparently Yafu is having a bug when it is factoring a number which is consisting of many small factors.
This is the main reason for why I usually do not choose to be doing just such a thing. Factoring a number gives like a C230 from a C240 and the rest or remainder of the number is being listed without further factorization or stating whether it is composite or not. That is when using the ecm command. Using ecm(ans,30) instead, where ans is the current number (or the number currently being factored makes it possibly to return the result to the Factor Database either using the Auto detect (slow) format or Yafu output at the bottom of the pulldown menu. When using the ecm(ans,30) command, the remainder of the number is being listed as a P1234567891 (or P10). For the ecm(ans) command, I only get 1234567891 as the remainder of the result. This is a silly and unncessesary bug which needs to be fixed as soon as possible! 
20141205, 08:09  #327 
Jun 2014
2^{3}·3·5 Posts 
ECM runs ECM factoring on the number, it isn't supposed to completely factorise the number.

20141223, 21:58  #328 
Feb 2013
2·229 Posts 
One small thing I notice in the Yafu output is that it is a bit cramped at times.
Really I prefer to compress things myself and also when writing stuff trying to even out the sentences and not put everything in one single line or paragraph. But just one blank line for separating the different result elements in the output gives a better look or appearance of things. There are a couple of times where I am missing this blank line. Hopefully a small bug that could be fixed. Last fiddled with by storflyt32 on 20141223 at 21:59 
20150209, 00:19  #329 
Basketry That Evening!
"Bunslow the Bold"
Jun 2011
40<A<43 89<O<88
3×29×83 Posts 
No idea if this is even really a yafu issue or not, but here it is http://mersenneforum.org/showthread....947#post394947

20150209, 00:55  #330 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
2×4,663 Posts 
Of course it is a yafu issue! [/semisarcasm]
yafu should be patched to reply: x^41 = (x1)(x+1)(x^2+1) ...which immediately takes care of that particular example: it gets fully factored. More generally, yafu should not ever accept a reducible polynomial as a factorization hint. Either bluntly dump it back to the user, or factor it algebraically internally, and only then use the part that contains the input (or as in this case: take gcd, and divideandconquer). 
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