20070201, 00:45  #1 
(loop (#_fork))
Feb 2006
Cambridge, England
2×3×29×37 Posts 
2^772+1 has started
Since about 11pm on 25th January, my machine's been sieving on 2^772+1.
So I guess we'll see the factors of 10^229+1 around the end of February. I notice that people seem to be doing the linear algebra on dualG5 systems; is the code multithreaded, or are G5 systems just convenient platforms in which to put enough memory to fit an SNFS matrix? Once I've convinced Mastercard to smite appropriately the supplier of the Kentsfield system I bought whose PSU exploded after three hours' operation, and who took the machine back and refunded me the price of the PSU (I'm guessing end February for this) I'll have a Kentsfield (quad Core2 2.66GHz); I'd be happy to run LA or filtering on it if it's a useful platform for that, though I appreciate that filtering seems more to require knowledge of the black arts than pure gigaops. 
20070201, 09:00  #2  
Bamboozled!
"πΊππ·π·π"
May 2003
Down not across
10,949 Posts 
Quote:
Quote:
The choice of systems is dictated by what we own. It turns out that my box is markedly faster than Richard's for reasons we don't really understand. My guess is that the SSE2 instructions are particularly effective. Quote:
We'd need to know what OS you'll be running (Linux would be by far the easiest for us, hint, hint ) and how much memory it has. Unfortunately, linear algebra in particular uses a lot of memory and at least 2G RAM is needed for the matrices we're now doing. My system has 2.5G and Richard's 4G, I believe. Paul 

20070202, 14:26  #3 
(loop (#_fork))
Feb 2006
Cambridge, England
2·3·29·37 Posts 
I originally ordered the machine with 2G, once I've got my money back I'll order a 4G system. It doesn't seem possible to put more than 4G into an Intel singlesocket system (only four slots, and 2GB DDR2 DIMMs appear not to exist), but 4G ought to suffice.
It will run Linux, probably Ubuntu since Canonical seem to have hired half the Cambridge geeks of my acquaintance as Ubuntu developers. I assume that the linear algebra is done on 128 bitvectors in parallel using SSE2, so the large Core2 caches aren't going to fit the whole V ... I assume the linalg does all the obvious tiling optimisations so it tries to stay within cache, I don't know how nicely that'll work in the twosharedcaches environment. Will be interesting to find out. [is the linear algebra routine available as sourcecode, or is it more tightly licensed like the linesiever executable?] 
20070202, 14:28  #4 
(loop (#_fork))
Feb 2006
Cambridge, England
1926_{16} Posts 
Ah, I'd inadvertently selected a 'show only affordable memory' option; Crucial can sell me 2GB DDR2 DIMMs, but they cost four times as much as 1GB DIMMs, and my budget is finite.

20070321, 14:38  #5 
Nov 2003
2^{2}·5·373 Posts 

20070321, 19:49  #6 
Jun 2003
The Texas Hill Country
3^{2}·11^{2} Posts 
Bob,
We are currently nearing 50% of the sieving on 2,772+. It is projected to run until mid June since the U Gent computers are presently busy on another computation and expect to remain so until some time this Summer. As a result, I have not worried about "what's next" to any great extent. I know that Paul and Bruce have discussed some possibilities taking Bruce's ECM work into account. Richard 
20070420, 15:21  #7 
(loop (#_fork))
Feb 2006
Cambridge, England
2·3·29·37 Posts 
Would it be useful for me to run some lattice sieving on 2,772+ (what's the polynomial and the rat/alg bounds?), or would that contend unhelpfully with the linesievers?

20070420, 16:06  #8  
Nov 2003
2^{2}×5×373 Posts 
Quote:
almost impossible to predict in advance. I believe that it would be useful. 

20070510, 11:55  #9  
Jun 2005
lehigh.edu
2^{10} Posts 
next number candidates?
Quote:
among the available More Wanted numbers I reported Quote:
considered? The current number has difficulty 233, which seems to have been a bit long without the Gent cpus. The wanted/most_wanted base2s seem to be harder yet (and will move up on the list to be more attractive on the next list); we finished the base5s; and the remaining base10s also look harder. [cf. 10,239+/ at (233 vs 239); likewise 10,236+ (236), with 10,232 at 232.] Bruce Last fiddled with by bdodson on 20070510 at 11:58 Reason: typo 

20070510, 14:42  #10  
Nov 2003
16444_{8} Posts 
Quote:
5,317, 323 6,283 284+, 292+ 7,263, 269, 271 268+ 

20070510, 21:21  #11  
Jun 2005
lehigh.edu
10000000000_{2} Posts 
Quote:
being the base6 and base7 ones on the current More Wanted list. We've already done four base5's; other things being equal (such as ease of polyn and sieving range estimation; snfs difficulty), Cunningham etiquette suggests wanted numbers before unwanted (even just notquiteyet wanted ones), yes? That's two of your nine that I didn't mention (the base 5s), the third one being 6, 292+. If this were an issue of a vote, I'd vote to pick from the six ones on the SelfridgeWagstaff list first, then the other three. In any case, neither six nor nine is the correct order of magnitude; the intended question is which two numbers ought to be done next (three, maybe if the Gent cpus return). In terms of ecm pretesting, four of the "wanted six" have already had 2*t50, which is the level I've been working to (since Bob's 6,281 c162 with three factors in ecm range). Looks like it wouldn't hurt to take the two large base7's early (as they're already in the Opteron queue). Any other suggestions from c190c233, difficulty 220229.9, that seem plausible candidates to be one of the next three? The base5s are already done (to 2*t50). I can also do the large base6 early (just on case someone decides on that one? Or to see to larger likelihood that it's going to need sieving, also). There, that covers Bob's new suggestions. Any others? And which 23 should be next (any other candidates?). Bruce 

Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Getting started  10metreh  Aliquot Sequences  20  20210727 12:51 
Getting started  XYYXF  XYYXF Project  11  20200714 01:48 
getting started with ubuntu 8.04  will_la_bete  Linux  1  20090509 10:19 
How do I get started?  KEP  Operation Billion Digits  3  20050509 08:02 
Getting Started / Welcome  Citrix  Prime Sierpinski Project  0  20040618 22:25 