20050810, 12:09  #1 
Apr 2003
772_{10} Posts 
Low n ECM Factoring Reservation
To make handling of the ECM reservations easier i have moved it to this thread.
Here is a list of the values that need ECM work. All other noted p1 results by gribozavr P+1 work done so far (gribozavr) 237019*2^1006+1: P+1: 3 runs with B1=1e9, B2=1e12. No factor found. P1 work done so far (gribozavr) P1 on all composites: B1=1e7, B2=1e10. (done by gribozavr) 237019*2^1006+1 (P1: B1=1e10 B2=1e13) 152267*2^1059+1 (P1: B1=1e10 B2=1e13) 258317*2^1359+1 (P1: B1=1e9 B2=1e12) [obsolete, prime found] 265711*2^1824+1 (P1: B1=1e10, B2=1e13) [obsolete, prime found] B1=11000000 (4590 curves) (45 digit level) 237019*2^1006+1 :2250 curves done by hhh [unreserved] 152267*2^1059+1 gribozavr [reserved] 168451*2^1116+1 :2250 curves done by hhh [unreserved] 79817*2^1191+1 222113*2^1221+1 152267*2^1707+1 265711*2^1128+1 [obsolete, prime found] 258317*2^1167+1 [obsolete, prime found] 258317*2^1311+1 [obsolete, prime found] 258317*2^1359+1 [obsolete, prime found] B1=3000000 (2440 curves) (40 digit level) 237019*2^1726+1 258317*2^1479+1 [obsolete, prime found] 265711*2^1824+1 gribozavr [reserved] [obsolete, prime found] 222361*2^1912+1 [obsolete, prime found] 7 numbers left. Results found: 16128337303431960646300665617239669  149183*2^1309+1 has a factor B1=1000000, B2=839549779 (ecm default). by gribozavr 57502772233796094957626382483691  237019*2^1330+1: Factor found in step 2:by Mystwalker 1109963100575400207621326621023  90527*2^1511+1: Factor found in step 2: by fetofs 4956781252585267514049309709366520124023  265711*2^1344+1: Factor found in step 2: by gribozavr 72747115712011935356411692471357381223  79309*2^1694+1: ECM: 220 curves with B1=3e6, B2=4016636513 (ecm default). Factor found in step 2: by gribozavr 896948379820920588037275255750180735407209  237019*2^1582+1: B1=3e6, B2=5706890290, polynomial Dickson(6), sigma=1483464917032609 found by hhh Last fiddled with by hhh on 20090117 at 01:24 
20050810, 19:23  #2 
Dec 2004
13×23 Posts 
Have you guys done p1 factoring on these numbers. Wlipp said he generally does a p1 and then 3 p+1 3 levels higher than they ecm.
Personally I'd suggest since this is all in good fun. make sure each k/n pair is B1=B2=4.2G this is the limit of proth, took a little less than a day for a n=991. 
20050814, 04:21  #3 
Mar 2003
New Zealand
13·89 Posts 
If you want to make the most of your CPU time then you should probably use Prime95 for the stage one step on these numbers (at least until the next version of gmpecm comes out). On a 2.66GHz P4 the Prime95 24.14 times for 258317*2^1167+1 with B1=1,000,000 are:
stage 1: 23.6 sec stage 2: 11.6 sec for gmpecm 6.0.1 on the same number with B2=100*B1: stage 1: 94.8 sec stage 2: 7.9 sec (B2=100*B1) stage 2: 30.3 sec (gmpecm default) The higher the exponent the more of an advantage Prime95 will have over gmpecm. 
20050814, 09:38  #4  
Mar 2005
Internet; Ukraine, Kiev
11×37 Posts 
Quote:


20050814, 10:41  #5 
Aug 2002
20D_{16} Posts 
ECM2=24737,2,991,1,11000000,2420000000,10
will do 10 curves on 24737.2^991+1 with B1=11000000 and B2=2420000000 Now since you want to do only stage1 put B2 =1 not zero one! ECM2=24737,2,991,1,11000000,1,10 Don't forget to use B1 =1 and B2= the prime95 B1 value followed by a  and the B2 value you want when you run the ECM ecm6k7.exe dickson 12 resume resume23.txt >>ECM6Aoutput23.txt 1 1100000018000000000 
20050826, 14:15  #6  
Jul 2004
Potsdam, Germany
3×277 Posts 
From the readme file of gmpecm6.0:
Quote:
4.2G would be somewhere between 60 and 65 digit  here, P1 is not efficient anymore anyway. Plus, you'd have big problems with B2... 

20051002, 00:02  #7  
Mar 2003
New Zealand
13·89 Posts 
Quote:
You can work out for yourself exactly what the optimal B2 value to use by running gmpecm with the v parameter on a few curves using different values of B2. Note the expected time to find a factor for each curve, and use the B2 value that minimises this time. In my experience on a P4 the optimal value for B2 is usually quite close to when the time spent in stage two is about half of the stage one time, regardless of whether you use GMPECM or mprime for stage one. If you use GMPECM for both stages then the default B2 is fine for smaller numbers, but it seems to become too small as the size of the number increases. This might depend a bit on the hardware used. If your machine is relatively more efficient in the stage one code than a P4 then the smaller B2 might be reasonable. Note that GMPECM may not use the exact value of B2 that you specify on the command line, the actual value used is the B2' value shown at the beginning of stage 2 when using the v switch. 

20060202, 22:30  #8 
Mar 2005
Internet; Ukraine, Kiev
407_{10} Posts 
If anyone wants to run only stage 1 of ECM/P1/P+1, I can continue and run stage 2. Especially P1/P+1  I have 1Gb of ram, so I can do stage 2, but stage 1with B1=1e10 is rather long (265711*2^1824+1 P1 stage 1 with B1=1e10 took about 30 hours).
Last fiddled with by gribozavr on 20060202 at 22:33 
20060422, 21:39  #9 
Apr 2003
2^{2}×193 Posts 
Hi,
if somebody is interested to do some ecm work i have set up an ecmnet server. It contains all the not reserved composited from this thread plus some more from the beta test ranges. The server is reachable under: www.pspproject.de port: 8194 If possible put your nickname into the "id=" in ecmnetclient.cfg. If not please mail me for which psp nickname i should use for the email address that is reported from cemnet in case you find a factor. And no sorry i have no ecmnet client as binary ready for download. Lars Last fiddled with by ltd on 20060422 at 21:40 
20060422, 21:49  #10 
Mar 2005
Internet; Ukraine, Kiev
627_{8} Posts 
Just an update: I'm still working on reserved composites and have some unreported curves. I'm working splitstage: Celeron 1.2Ghz does stage 1, Athlon64 3000+ does stage 2.

20060422, 22:13  #11 
Apr 2003
2^{2}·193 Posts 
@gribozavr:
Your reservations will stay untouched and it will be allways possible to reserve other k/n pairs for local ecm testing. They will be disabled on the ecmnet then. I am only playing with the server and it was easy to set up the ecmnet server so i did it. Lars 
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