20040923, 16:49  #1 
Mar 2003
New Zealand
13×89 Posts 
Want to trade work?
Would anyone like to trade their P3, Athlon, etc. with my Celeron for a few weeks? It is sse2capable, 2.88GHz, and good for GIMPS trial factoring. (GIMPS name is 97030014/cel). It takes about 19 hours to TF one of the current exponents in the 2710xxxx range from 2^62 to 2^67. If you are doing this sort of work on a nonsse2 machine, try adding one of these lines to your worktodo.ini and note the time taken for each curve:
ECM=737,11000000,1,1,0,0,1,0 ECM=749,11000000,1,1,0,0,1,0 (Don't report it to the primenet server, and you may have to temporarily increase the OutputIterations line in prime.ini to OutputIterations=999999999 to avoid masses of unwanted output affecting the timing). My celeron takes 178 seconds (for the equivalent work by a slightly different method) for each of these, which means I can do about 385 curves in the time it takes to TF from 2^62 to 2^67. If your machine can do significantly more than this (in the time it takes to do the same TF on the same machine) then it might be worthwhile trading work for a while. I want up to 5000 each of these curves. You can send me worktodo.ini entries for whatever you want done on my Celeron. (If you haven't done ECM before then the work will just involve downloading this file http://www.mersenne.org/gimps/lowp.txt into your Prime95 directory, adding the line "GmpEcmHook=1" to prime.ini and an entry ECM=737,11000000,1,N,0,0,1,0 to worktodo.ini, where N is the number of curves you want to do, and then sending me a copy of the resulting results.txt file, which may grow to a few MB. It will use no more memory than trial factoring does.) edit: If you have a sse2capable machine then it will not be worthwhile trading, but if you are interested in the times anyway then the equivalent lines to put in the worktodo.ini are: ECM=1474,11000000,1,1,0,0,0,0 ECM=1498,11000000,1,1,0,0,0,0 Last fiddled with by geoff on 20040923 at 16:57 
20040924, 12:10  #2 
Mar 2003
New Zealand
13×89 Posts 
I timed my old 166MHz Pentiummmx for comparison. It takes 738 hours to complete TF for a 2710xxxx exponent from 2^62 to 2^67 on this machine, and 2075 seconds per ECM curve on P737. This means it can do 1280 curves in the time it takes to do one TF, compared to the Celeron's 385.
If you had a machine like this doing GIMPS TF assignments and wanted to trade, then you would do 705 ECM curves for me and I would do one TF for you. It would take you 406 hours work and you would get 738 hours in return. I would do 19 hours work and get 35 in return. We would each get over 80% more work done! I realise there are probably not many 166MHz machines doing TF any more, but perhaps the numbers will work out like this for a P3 or Duron too? 
20040924, 12:39  #3 
"Nancy"
Aug 2002
Alexandria
9A3_{16} Posts 
I'm currently generating F12 residues on my home P3500, but P737 and P749 would make better use of the length 32 FFT than F12 makes of length 256. Would you like to trade P737/P749 B1=11M residues against M32768 B1=44M residues? The exchange rate should be ~1:178. A curve takes me ~10 minutes, so I should be able to produce ~70100 residues a day.
Alex 
20040924, 15:01  #4  
Mar 2003
New Zealand
13×89 Posts 
Quote:


20040924, 22:38  #5 
Mar 2003
New Zealand
10010000101_{2} Posts 
It turns out M32768 is not so good on the Celeron, it would take 8hr 45min per curve. I will do them on a 2.9GHz P4/HT instead, it does M32768 B1=44M in 4hr 40min and P737/749 B1=11M in 152sec. How does that affect the exchange rate? At 1:178 I would be 61% better off :)

20040925, 08:58  #6 
"Nancy"
Aug 2002
Alexandria
2,467 Posts 
I wouldn't have a problem with keeping the exchange rate at 1:178. That's the ratio derived from exponent and B1, and for the purpose of optimizing total throughput, I think it makes sense to rate machines only be how much work they get done rather than penalizing extremely efficient machines. Btw, I factored the exponent in linearly instead of n*log(n), but lets not be overly picky, especially if the error is in my favour!
Doing 2x5300 curves will probably take more than 3 months on my P3 which may be longer than you'd like to wait, so if you would like to barter residues with someone else as well, please feel free to! Alex 
20040925, 18:23  #7 
Mar 2003
New Zealand
13·89 Posts 
OK, lets just trade 30 of M32768 for 5300 of P737 for now and see how that goes.
If anyone else wants to trade work then post here. 
20041008, 19:14  #8 
Jul 2004
Potsdam, Germany
831_{10} Posts 
I can throw in a Duron @ 800 (or was it 850?) MHz running Linux. Interested?

20041009, 07:44  #9  
Mar 2003
New Zealand
13×89 Posts 
Quote:
If anyone has an Athlon handy I would also be interested in finding out whether an Athlon is any faster dollar for dollar than a Duron at this sort of work. I am thinking of putting together a budget AMD system and the Duron 1800MHz chip is very nicely priced. 

20041009, 10:27  #10  
Banned
"Luigi"
Aug 2002
Team Italia
4802_{10} Posts 
Quote:
Tell me what I have to check Luigi 

20041009, 16:58  #11  
Jul 2004
Potsdam, Germany
3×277 Posts 
Quote:
To do this, you have to 1) download PRP3 from http://www.mersenne.org/gimps (either Windows (.zip) or Linux (.tgz) version) 2) make a file with the following contents: Code:
1000000000:P:0:2:257 222113 1226837 222113 1226901 Quote:
Code:
GMPECM 5.1beta [powered by GMP 4.1.3] [ECM] Input number is 2831308076778128190043701447911173778911219952694768521472311451 0480121 (189 digits) Using B1=11000000, B2=25577181640, polynomial Dickson(12), sigma=3011671549 Step 1 took 652909ms Step 2 took 440633ms talis@Suse:~/bin/gmpecm> ./ecm 11e6 < p749 GMPECM 5.1beta [powered by GMP 4.1.3] [ECM] Input number is 283130807677812819004370144791117377891121995269476852147231145147056120358331224118442174975812354857658437068455078687726853215164019399440647197130552010023632611590549058806284940480121 (189 digits) Using B1=11000000, B2=25577181640, polynomial Dickson(12), sigma=4161096674 Step 1 took 652649ms Step 2 took 440083ms Is the prime95 ecm'ing faster? 

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