mersenneforum.org Resume linear algebra
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 2018-01-21, 14:35 #1 Timic   Jan 2018 11 Posts Resume linear algebra I used Brian Gladman's python script which uses GGNFS and MSIEVE to factor 155 digit number, but it threw errors when it came to linear algebra step (I assumed it was because of RAM), so I moved it to another machine with more RAM. When I ran the script there, it started sieving from beginning (so the .dat file was removed). Do I have to run some command from cmd to resume linear algebra step? By the way, I followed this guide.
 2018-01-21, 17:09 #2 chris2be8     Sep 2009 2,027 Posts If you still have the .dat file somewhere, eg on the original machine, you can probably restart linear algebra (you may have to re-build the matrix though). If you have lost the .dat file you will have to re-run the whole job. Make a backup copy of the .dat file (and everything else in the directory) before you start experimenting though. Can you post the log from the failing run so we can see what went wrong. Also a directory listing of where you were running it. You probably need to re-run the msieve step in the log, replacing -nc2 with -ncr, if you have all the files from the failing attempt at linear algebra. If that fails try running msieve with -nc to rebuild the matrix. I assume you are running Windows from your mention of running things under cmd. What version is it though? Chris Last fiddled with by chris2be8 on 2018-01-21 at 17:14 Reason: Clarify to back up every related file.
 2018-01-21, 18:32 #3 VictordeHolland     "Victor de Hollander" Aug 2011 the Netherlands 100100110002 Posts Without the relations and the matrix you can't finish the factorization. You need the matrix to resume linear algebra (-ncr to resume or -nc2 to rebuild) and the relations in the sqr fase (-nc3). Last fiddled with by VictordeHolland on 2018-01-21 at 18:33
 2018-01-21, 19:25 #4 Dubslow Basketry That Evening!     "Bunslow the Bold" Jun 2011 40
 2018-01-21, 20:04 #5 EdH     "Ed Hall" Dec 2009 Adirondack Mtns 71468 Posts But, if he didn't rerun on the original machine, the relations should still exist there. The OP would also need the original poly file, or fb, IIRC. On the original machine, there should be a compressed file with all the original relations, too. Or, is my memory really bad, or the comparison between Win and linux too far removed?
 2018-01-21, 21:19 #6 VictordeHolland     "Victor de Hollander" Aug 2011 the Netherlands 49816 Posts The dir should look something like this on Windows (note this is an old dir) Code: 18-04-2016 18:47 12.761.511.205 C204_119_99.dat.gz 30-12-2015 22:47 99.223 Changes 31-12-2015 22:45 864.110 libmsieve.a 11-09-2015 01:38 56.978 libwinpthread-1.dll 31-12-2015 22:45 3.175.900 msieve-svn988-x64-sandybridge.exe 22-04-2016 01:13 23.917.535.851 msieve.dat 29-04-2016 06:01 570.056.176 msieve.dat.bak.chk 29-04-2016 07:03 570.056.176 msieve.dat.chk 23-04-2016 00:51 509.858.000 msieve.dat.cyc 29-04-2016 07:36 114.010.464 msieve.dat.dep 23-04-2016 00:51 6.132.670.652 msieve.dat.mat 18-04-2016 15:21 429 msieve.fb 18-04-2016 15:21 502 msieve.poly 11-09-2014 14:01 185.976 pthreadGC2.dll 11-09-2014 14:01 82.944 pthreadVC2.dll 30-12-2015 22:47 25.290 Readme 30-12-2015 22:47 57.946 Readme.nfs 30-12-2015 22:47 7.987 Readme.qs 18-04-2016 15:21 205 worktodo.ini 17-08-2015 17:19 90.250 zlib1.dll
2018-01-22, 15:43   #7
Timic

Jan 2018

11 Posts

Hi, I'm sorry for the late reply.

The problem is, this script ran on a really bad virtual machine, which has 4GB RAM and 4 core CPU with 1 thread each. Windows already used 50% of RAM so I guess msieve didn't have enough memory to complete linear algebra. I have Windows 2012 R2 by the way.

So, the minute I stopped the linear algebra step, I saved everything. I attached 2 pictures that show all files (it's zipped, so I couldn't ls it through cmd).

The full log is in attachments.
Attached Thumbnails

Attached Files
 rsa.log (525.5 KB, 302 views)

 2018-01-22, 15:54 #8 wombatman I moo ablest echo power!     May 2013 1,741 Posts What RSA number are you trying to break?
 2018-01-22, 17:09 #9 Timic   Jan 2018 11 Posts This one: 1772352223689553499523382657591107586734440334822954296365208356693849378633858324876899946660923527875550194354495596668114847388151261943936272297881447 (154 digits)
 2018-01-22, 17:10 #10 chris2be8     Sep 2009 202710 Posts I only use Linux, so I'm guessing a bit. But try the following after extracting the files onto another system: msieve -s .\rsa/rsa.dat -l .\rsa/rsa.log -i .\rsa/rsa.ini -nf .\rsa/rsa.fb -t 4 -ncr If that fails try restarting -nc2 from scratch: msieve -s .\rsa/rsa.dat -l .\rsa/rsa.log -i .\rsa/rsa.ini -nf .\rsa/rsa.fb -t 4 -nc2 If either of those worked then run: msieve -s .\rsa/rsa.dat -l .\rsa/rsa.log -i .\rsa/rsa.ini -nf .\rsa/rsa.fb -t 4 -nc3 But if they both failed try rebuilding the matrix (this will try to run all msieve steps in one go): msieve -s .\rsa/rsa.dat -l .\rsa/rsa.log -i .\rsa/rsa.ini -nf .\rsa/rsa.fb -t 4 -nc Obviously keep the backup zip files safe until you have factored the number. If you run: msieve -h you will get a brief summary of what options msieve accepts. That should help you work out what it wants (eg after -l put the name of the log file. Chris
 2018-01-22, 18:11 #11 Timic   Jan 2018 138 Posts I ran (added verbose too) msieve -v -s .\rsa/rsa.dat -l .\rsa/rsa.log -i .\rsa/rsa.ini -nf .\rsa/rsa.fb -t 4 -ncr and it threw an error: cannot open matrix checkpoint file, so I guess that won't work. Tried the -nc2, it built the matrix and is now performing linear algebra, BUT I get these errors: lanczos halted after x iterations (dim = x) linear algebra failed; retrying memory use: 868.8 MB lanczos error: submatrix is not invertible Those were the same errors as on the virtual machine, I thought they were because of memory, but I have 16 GB of RAM here... Is this normal? By the way, I'm using the same .dat and .dat.cyc.

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