20040816, 12:28  #12  
Aug 2004
way out west
2×13 Posts 
Quote:


20040816, 16:21  #13  
Bamboozled!
"πΊππ·π·π"
May 2003
Down not across
10101001011110_{2} Posts 
Quote:
We have several systems around that can perform the linear algebra on a 5M matrix in around a month. Wacky has his dualG5 box which solved the 10,227+ matrix a month or so back. Another person, (I won't name him because I don't yet know whether he wants publicity) can also run a matrix of that size in around that amount of time. What's required is a reasonably modern cpu (2GHz or more) and a fair amount of memory. At this level, 1Gb isn't quite enough, 1.5Gb is sufficient and 2Gb is plenty. Let us say that in the good old days we could do a 5M matrix in two weeks on the cluster and that these days we need six weeks on a single machine. To maintain the same throughput then, we need three chunky single machines. This is easily obtainable. In practice, we would like to have more than three machines to allow for some flexibility and to allow for nonuniform work flows. Anyone who has such a machine and is prepared to devote a cpumonth or more to a single computation is encouraged to volunteer. Unfortunately the license restrictions on the code (it's neither our code nor our license) means we can only provide binaries but we can do so for almost all common architectures and operating systems. If a really big matrix is produced as a consequence of an unusually large computation (remember M811?) there is an excellent chance that some of our friends with access to large clusters will be able to help out in a oneoff situation. Paul 

20040816, 16:34  #14  
Nov 2003
2^{2}·5·373 Posts 
Quote:
This was for 2,661+. It required just over 1Gbyte of memory. The time to solve the matrix grows a little worse than quadratically in the number of rows. The actual run time is O(N^2 d) where d is the average number of lit bits per row. d grows very slowly (theoretically as loglog(C)) where C is the composite being factored. N (#rows) grows with the square root of the sieve time. Bob 

20040817, 11:01  #15 
Jan 2004
7·19 Posts 
is there any why we can't use anymore the cluster at microsoft cambridge ?
what type will be required for a matrix similar to the one we got for M811? Richard, how many RAM has ur dualG5, btw, 2G ? a 64bits architecture would help to ur postlinear processing ? cause i wonder if an opteron could really help with postprocessing. Last fiddled with by junky on 20040817 at 11:02 
20040817, 11:48  #16 
Jun 2003
The Texas Hill Country
3^{2}×11^{2} Posts 
We no longer have access to the cluster at Microsoft Research Cambridge because the individual who was providing that access is no longer employed there.
My DualG5 has 2GB of RAM (except on Thursdays when it has 2.5GB) The 64 bit registers certainly don't hurt when it comes to doing bitvector operations. However, I suspect that the FSB memory architecture is equally important. 
20040817, 15:31  #17  
Sep 2002
Vienna, Austria
219_{10} Posts 
Quote:
11^1991=2.5.797.140893.18242336369.4645373755026923.C173 Last fiddled with by wpolly on 20040817 at 15:34 

20040818, 00:19  #18  
Aug 2004
New Zealand
3^{2}·5^{2} Posts 
machines
Quote:
While I tend to use faster machines with less memory for the matrix step, I find the 16GB machine handy for some of the filtering step (at least when working with the Franke code base). 

20040823, 02:37  #19 
Jan 2004
7×19 Posts 
since the new project (11_199M) has started, can we know what's the estimated time for tha project ?
what type of machine do ya plan to use to complete the postprocessing of the 3_491P ? the Richard's DualG5 ? thanks. 
20040826, 19:45  #20 
A01_{16} Posts 
Looking at the couple of days stats ... I hope should be finished within 10 ~ 15 days.

20040826, 22:50  #21 
Aug 2004
way out west
2·13 Posts 
Yeah, we are cruising through this project. So, to bring things full circle...
What's next? 
20040909, 03:40  #22 
Aug 2004
way out west
2×13 Posts 
^bump
Additionally, is there any chance of updating the NFSNET home page to reflect current activities? [Best South Park  Jimmy voice]I mean, come on[/voice], it was last updated in June... 