20070430, 13:26  #1 
Apr 2005
15_{8} Posts 
ggnfs sqrt problem
Hi,
I am trying to factor a c129 from the xyyxf project. (The number is 689248390756594092329903555441060933187672009587156714157714459911067848381094129751231275207217559323589590068177837430265561551) However, when I run the sqrt program, I either get the trivial factorization 1*N, or the error message posted beneath. Any idea on how I can fix this? ggnfs/Version reads: 0.77.120060513 Sun May 14 09:18:57 UTC 2006 The system is a Pentium 4 running Ubuntu 6.06. Cheers, Hallstein  ... Reading relations from rels.bin.23... The final square should be: 130680677895632184865139317000365589321504868538119170411575793060617878224349779001039329223849671202761057909376525885051074735 We used 2277256 (a,b) pairs. Error: Odd exponent found: AFB[11] has exponent 1! 
20070430, 13:48  #2  
Nov 2003
2^{2}·5·373 Posts 
Quote:
I don't use GGNFS, but I strongly suspect that this is a linear algebra error and not a sqrt error. Is there a way to verify the LA solution sets? 

20070430, 15:01  #3  
May 2003
Warsaw
2·7 Posts 
Quote:


20070430, 20:29  #4 
Jul 2003
So Cal
2^{3}×257 Posts 
It can also be completed using the latest version of msieve. See
this post for details: http://www.mersenneforum.org/showpos...&postcount=403 Greg 
20070501, 06:17  #5  
Apr 2005
13 Posts 
Quote:
I tried this just now. But when I ran msieve, I got an enormous amount of errors messages: 90% of the error messages were on the form "error 10 reading relation X" The remaining were "error 5..." Then, in the linear algebra stage, it segfaulted. The last message to be written to the log was "using 32 quadratic characters above 134217362" 

20070501, 07:51  #6 
Jul 2003
So Cal
2^{3}·257 Posts 
This is a large GNFS factorization, isn't it? Version 1.19 doesn't support 64bit a values, which you have in abundance. The next version of msieve, hopefully due any day now, will support 64bit a values and therefore should work.
Greg 
20070501, 08:45  #7  
(loop (#_fork))
Feb 2006
Cambridge, England
6,379 Posts 
Quote:
I haven't had a segfault in linalg from msieve, though that may be something to look forward to when my C200 SNFS finally accumulates enough relations to build a matrix. ggnfs is failing on that run: procrels dies during the makemorefiles step roughly at the point where the total size of the rels.bin.* files exceeds 2^32 bytes, in such a way as to destroy the rels.bin.*. Thankfully, I save unprocessed relations. 

20070501, 12:51  #8 
Tribal Bullet
Oct 2004
2·3·19·31 Posts 

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