20140316, 22:32  #1 
(loop (#_fork))
Feb 2006
Cambridge, England
2·29·109 Posts 
That's odd ... ubuntu13.10 ecm issue
I'd run about six thousand curves at 3e6 on the C174 cofactor of 5748.1525 to no avail (using GMPECM 6.4.2 as distributed with Ubuntu 13.10, on my Avoton box), and thought I ought to do a bit of GPU ECM.
The first job ran (as a screen session) for six hours then stopped and the screen session vanished. Cursing, suspecting some sort of GPU problem (I'd just installed a second GTX580 card), I ran again from a command line in a screen session and it said Code:
pumpkin@pumpkin:~/ecmbulk$ ~/cudaecm/trunk/ecm v gpu save 5748.1525.1.s1 1e8 1 < 5748.1525.n GMPECM 7.0dev [configured with GMP 5.1.2, enableasmredc, enablegpu, enableassert, enableopenmp] [ECM] Running on pumpkin Input number is 240374937214123387734825980441485328571760198890188986168556177043725516179623977715973254104349268626550386607672381746223853794447671062771318068793196116019917029782728411 (174 digits) Using MODMULN [mulredc:0, sqrredc:2] Computing batch product (of 144266969 bits) of primes below B1=100000000 took 7117ms GPU: compiled for a NVIDIA GPU with compute capability 2.0. GPU: will use device 0: GeForce GTX 580, compute capability 2.0, 16 MPs. GPU: Selection and initialization of the device took 9ms Using B1=100000000, B2=1, sigma=3:42277881023:4227788613 (512 curves) dF=0, k=0, d=0, d2=0, i0=0 Expected number of curves to find a factor of n digits: 35 40 45 50 55 60 65 70 75 80 367 1919 11140 71026 492358 3680463 2.9e+07 2.5e+08 2.4e+09 2.7e+10 Computing 512 Step 1 took 848302ms of CPU time / 21208554ms of GPU time Throughput: 0.024 curves by second (on average 41422.96ms by Step 1) ********** Factor found in step 1: 863037161444255167 Found probable prime factor of 18 digits: 863037161444255167 Probable prime cofactor 278522116952491803716089582283308807148257435762918539361376385659876790193555766353740096713002930457497552258688221497624585776194022548540546514299573733 has 156 digits At least I didn't run GNFS! Last fiddled with by fivemack on 20140316 at 22:43 
20140316, 23:55  #2 
Just call me Henry
"David"
Sep 2007
Cambridge (GMT/BST)
2^{2}·1,433 Posts 
Have you tried running exactly the same curve on the problem machines?

20140319, 17:09  #3 
"Ed Hall"
Dec 2009
Adirondack Mtns
3,373 Posts 
Just to add some more testing, I installed a brand new XUbuntu 13.10 (64bit) Virtual Machine and grabbed ECM from the repository. I used:
Code:
ecm v c 10 3e6 <ecmTestNum nothing! I then ran 100 curves with identical results: Code:
xubuntuvm@xubuntuvmVirtualBox:~/Math$ ecm v c 100 3e6 <ecmTestNum GMPECM 6.4.2 [configured with GMP 5.1.2, enableasmredc] [ECM] Running on xubuntuvmVirtualBox Input number is 240374937214123387734825980441485328571760198890188986168556177043725516179623977715973254104349268626550386607672381746223853794447671062771318068793196116019917029782728411 (174 digits) Using MODMULN [mulredc:0, sqrredc:2] Using B1=3000000, B2=5706890290, polynomial Dickson(6), sigma=1121040592 dF=16384, k=2, d=158340, d2=11, i0=8 Expected number of curves to find a factor of n digits: 35 40 45 50 55 60 65 70 75 80 324 2351 20272 201449 2247436 2.8e+07 3.9e+08 6e+09 1.1e+11 7.4e+15 Step 1 took 11503ms Using 21 small primes for NTT Estimated memory usage: 56M Initializing tables of differences for F took 11ms Computing roots of F took 294ms Building F from its roots took 792ms Computing 1/F took 459ms Initializing table of differences for G took 9ms Computing roots of G took 269ms Building G from its roots took 747ms Computing roots of G took 255ms Building G from its roots took 699ms Computing G * H took 268ms Reducing G * H mod F took 229ms Computing polyeval(F,G) took 1350ms Computing product of all F(g_i) took 7ms Step 2 took 5625ms Expected time to find a factor of n digits: 35 40 45 50 55 60 65 70 75 80 1.54h 11.18h 4.02d 39.94d 1.22y 15.32y 213.62y 3258y 60442y 4e+09y Run 2 out of 100: ... Run 100 out of 100: Using MODMULN [mulredc:0, sqrredc:2] Using B1=3000000, B2=5706890290, polynomial Dickson(6), sigma=1568360326 dF=16384, k=2, d=158340, d2=11, i0=8 Expected number of curves to find a factor of n digits: 35 40 45 50 55 60 65 70 75 80 324 2351 20272 201449 2247436 2.8e+07 3.9e+08 6e+09 1.1e+11 7.4e+15 Step 1 took 11951ms Using 21 small primes for NTT Estimated memory usage: 56M Initializing tables of differences for F took 11ms Computing roots of F took 301ms Building F from its roots took 733ms Computing 1/F took 404ms Initializing table of differences for G took 8ms Computing roots of G took 255ms Building G from its roots took 695ms Computing roots of G took 250ms Building G from its roots took 697ms Computing G * H took 239ms Reducing G * H mod F took 209ms Computing polyeval(F,G) took 1355ms Computing product of all F(g_i) took 8ms Step 2 took 5393ms Expected time to find a factor of n digits: 35 40 45 50 55 60 65 70 75 80 1.56h 11.33h 4.07d 40.44d 1.24y 15.52y 216.33y 3300y 61208y 4e+09y 
20140319, 17:19  #4  
"Mike"
Aug 2002
17027_{8} Posts 
Quote:
Code:
echo '240374937214123387734825980441485328571760198890188986168556177043725516179623977715973254104349268626550386607672381746223853794447671062771318068793196116019917029782728411'  ecm sigma 2945335458 5e4 

20140320, 00:34  #5 
"Ed Hall"
Dec 2009
Adirondack Mtns
3,373 Posts 
Code:
xubuntuvm@xubuntuvmVirtualBox:~/Math$ echo '240374937214123387734825980441485328571760198890188986168556177043725516179623977715973254104349268626550386607672381746223853794447671062771318068793196116019917029782728411'  ecm sigma 2945335458 5e4 GMPECM 6.4.2 [configured with GMP 5.1.2, enableasmredc] [ECM] Input number is 240374937214123387734825980441485328571760198890188986168556177043725516179623977715973254104349268626550386607672381746223853794447671062771318068793196116019917029782728411 (174 digits) Using B1=50000, B2=12746592, polynomial x^2, sigma=2945335458 Step 1 took 209ms Step 2 took 197ms xubuntuvm@xubuntuvmVirtualBox:~/Math$ From my Fedora host machine for the XUbuntu Virtual one: Code:
$ echo '240374937214123387734825980441485328571760198890188986168556177043725516179623977715973254104349268626550386607672381746223853794447671062771318068793196116019917029782728411'  ecm sigma 2945335458 5e4 GMPECM 6.4.4 [configured with GMP 5.1.1, enableasmredc] [ECM] Input number is 240374937214123387734825980441485328571760198890188986168556177043725516179623977715973254104349268626550386607672381746223853794447671062771318068793196116019917029782728411 (174 digits) Using B1=50000, B2=12746592, polynomial x^2, sigma=2945335458 Step 1 took 169ms Step 2 took 128ms ********** Factor found in step 2: 863037161444255167 Found probable prime factor of 18 digits: 863037161444255167 Probable prime cofactor 278522116952491803716089582283308807148257435762918539361376385659876790193555766353740096713002930457497552258688221497624585776194022548540546514299573733 has 156 digits Last fiddled with by EdH on 20140320 at 00:39 Reason: To add in the host machine run. 
20140320, 01:59  #6 
"Mike"
Aug 2002
7,703 Posts 
Hopefully we filled out the bug form properly!
https://bugs.launchpad.net/ubuntu/+s...m/+bug/1294929 
20140320, 02:56  #7  
Mar 2006
2^{3}·59 Posts 
Quote:
http://packages.ubuntu.com/saucy/math/gmpecm I let them know that this problem was discussed and solved on the ecmdiscuss list here: http://lists.gforge.inria.fr/piperma...ly/004234.html Hopefully, through either your bug report or my email the official Ubuntu gmpecm package will be updated to 6.4.4. 

20140401, 02:23  #8  
Mar 2006
2^{3}×59 Posts 
Well, the reply from the maintainers list was to file a backport request. You can see the response here and here
However, it looks like the easiest way to fill out a backport request is by someone who uses Ubuntu. You can see details about the process here One helpful quote from the backport page is: Quote:


20140408, 07:25  #9 
"Mike"
Aug 2002
7,703 Posts 
Ubuntu 14.04 (LTS) Beta 2:
Code:
$ echo '240374937214123387734825980441485328571760198890188986168556177043725516179623977715973254104349268626550386607672381746223853794447671062771318068793196116019917029782728411'  ecm sigma 2945335458 5e4 GMPECM 6.4.4 [configured with GMP 5.1.3, enableasmredc] [ECM] Input number is 240374937214123387734825980441485328571760198890188986168556177043725516179623977715973254104349268626550386607672381746223853794447671062771318068793196116019917029782728411 (174 digits) Using B1=50000, B2=12746592, polynomial x^2, sigma=2945335458 Step 1 took 136ms Step 2 took 79ms ********** Factor found in step 2: 863037161444255167 Found probable prime factor of 18 digits: 863037161444255167 Probable prime cofactor 278522116952491803716089582283308807148257435762918539361376385659876790193555766353740096713002930457497552258688221497624585776194022548540546514299573733 has 156 digits 
20140418, 21:28  #10 
"Mike"
Aug 2002
7,703 Posts 
Ubuntu 14.04 (LTS):
Code:
$ echo '240374937214123387734825980441485328571760198890188986168556177043725516179623977715973254104349268626550386607672381746223853794447671062771318068793196116019917029782728411'  ecm sigma 2945335458 5e4 GMPECM 6.4.4 [configured with GMP 5.1.3, enableasmredc] [ECM] Input number is 240374937214123387734825980441485328571760198890188986168556177043725516179623977715973254104349268626550386607672381746223853794447671062771318068793196116019917029782728411 (174 digits) Using B1=50000, B2=12746592, polynomial x^2, sigma=2945335458 Step 1 took 315ms Step 2 took 191ms ********** Factor found in step 2: 863037161444255167 Found probable prime factor of 18 digits: 863037161444255167 Probable prime cofactor 278522116952491803716089582283308807148257435762918539361376385659876790193555766353740096713002930457497552258688221497624585776194022548540546514299573733 has 156 digits 
20140418, 22:01  #11 
Just call me Henry
"David"
Sep 2007
Cambridge (GMT/BST)
2^{2}×1,433 Posts 
Is that the same pc? If so that is a huge time difference.

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