mersenneforum.org probably a stupid newbie question...
 Register FAQ Search Today's Posts Mark Forums Read

 2005-08-14, 20:57 #1 rpropper   Dec 2004 3 Posts probably a stupid newbie question... Hi all, Sorry if this is a stupid newbie question, but I was trying to use ECM to factor a number and didn't get any results. The program ran, reported how long it took to complete step 1 and step 2, and terminated. Here was the input/output: --- > echo "23648598680196674293592660374220409521936469024442760646483443630416927852665392144342050729272084591548384873564046388884876395326286172771630075104410787261" | ./ecm 11e7 GMP-ECM 6.0.1 [powered by GMP 4.1.2] [ECM] Input number is 23648598680196674293592660374220409521936469024442760646483443630416927852665392144342050729272084591548384873564046388884876395326286172771630075104410787261 (158 digits) Using B1=110000000, B2=680270182898, polynomial Dickson(30), sigma=4069758861 Step 1 took 4143830ms Step 2 took 1127850ms --- Does anyone know of parameters I need to use to actually get a factor for this integer? (I know it's not prime -- I already checked that with Primo). Thanks for your help!
 2005-08-14, 22:24 #2 cjohnsto   Jun 2005 3×5 Posts But you did get a result: 1 curve at B1=11e7 found no factors. To run multiple curves youneed to tell it to do so. I think the parameter is -c # where # is the number of curves to run. I also suggest you pipe the output to a file so you don't lose it if the computer crashes. echo "236...261" | ./ecm -c 100 11e7 >> out.txt &; tail -f out.txt This way you still see the output and have it saved.
 2005-08-15, 03:00 #3 rpropper   Dec 2004 3 Posts I see now. Thanks for the clarification. I had erroneously assumed that ECM would continue trying curves until it found a factorization. My mistake...thanks again :)
 2005-08-15, 07:57 #4 cjohnsto   Jun 2005 3·5 Posts No problem.
2005-08-15, 09:06   #5
xilman
Bamboozled!

"πΊππ·π·π­"
May 2003
Down not across

2B0F16 Posts

Quote:
 Originally Posted by rpropper Hi all, Sorry if this is a stupid newbie question, but I was trying to use ECM to factor a number and didn't get any results. The program ran, reported how long it took to complete step 1 and step 2, and terminated. Here was the input/output: --- > echo "236485986..." | ./ecm 11e7 GMP-ECM 6.0.1 [powered by GMP 4.1.2] [ECM] Input number is 236485986... (158 digits) sigma=4069758861
As a matter of interest, what is that number?

Paul

 2005-10-12, 15:00 #6 VJS     Dec 2004 4538 Posts You can keep it running until it finds a factor by adding the following in your command line. -one -c 10000 so something like this ecm -one -c 10000 B1 B2 results.txt Bascially the -one will allow the program to run until a factor is found overriding the -c switch. -c 10000 the number of curves to run until it stops in this case 10000 curves >results.txt dumps all of the screen output to a file, careful this file is overwritten each time you restart the client.
2005-10-12, 19:38   #7
smh

"Sander"
Oct 2002
52.345322,5.52471

100101001012 Posts

Quote:
 Originally Posted by VJS ecm -one -c 10000 B1 B2 results.txt >results.txt dumps all of the screen output to a file, careful this file is overwritten each time you restart the client.
If you put this in a batch file you'd better put >> results.txt so the results will be appended. You'll need to manually clean up the file ones in a while though.

<numbers.txt can be replaced with -inp numbers.txt

And if you add -nn it will run at idle priority

 2005-10-12, 20:05 #8 VJS     Dec 2004 13·23 Posts > vs >> Oh my god!!! Lets leave it at that. Is there a command to output the results to both the screen and a file??? Since I didn't know the >> I thought I'd ask. ----------------- You can also do -save file.txt and -resume file.txt for seperating stage1 and 2 if you wish. Perhaps, I should also ask is there a way to get prime95 to do stage1 of numbers from a file. And I mean decimal expansions not just k,n, from a worktodo.ini .
 2005-10-12, 23:01 #9 garo     Aug 2002 Termonfeckin, IE 22·691 Posts On UNIX you can use tee to do that. See man tee!
2005-10-13, 08:22   #10
xilman
Bamboozled!

"πΊππ·π·π­"
May 2003
Down not across

73·151 Posts

Quote:
 Originally Posted by garo On UNIX you can use tee to do that. See man tee!
On Windows you can get tee in several ways. My preferred route is to install SFU (Services for Unix) which is a free, albeit lengthy, download from microsoft.com

SFU gives you a large collection of Unix-like tools and a Unix-like environment all well integrated in your normal Windows environment. In particular, you get the gcc compiler and everything else necessary to build your own binary of ecm, optimized for your own cpu.

Other alternatives exist, Cygwin for instance, but I really believe that SFU is far superior.
I don't run a Windows box without SFU installed.

Paul

2005-10-13, 10:27   #11
ET_
Banned

"Luigi"
Aug 2002
Team Italia

25×151 Posts

Quote:
 Originally Posted by xilman On Windows you can get tee in several ways. My preferred route is to install SFU (Services for Unix) which is a free, albeit lengthy, download from microsoft.com SFU gives you a large collection of Unix-like tools and a Unix-like environment all well integrated in your normal Windows environment. In particular, you get the gcc compiler and everything else necessary to build your own binary of ecm, optimized for your own cpu. Other alternatives exist, Cygwin for instance, but I really believe that SFU is far superior. I don't run a Windows box without SFU installed. Paul

Do you mean that with SFU one could compile with GMP without the hassle of cygwin libraries? :surprised

Luigi

 Similar Threads Thread Thread Starter Forum Replies Last Post LaurV Information & Answers 14 2015-06-18 23:37 Uncwilly Lounge 19 2013-03-07 04:44 Biggles Prime Sierpinski Project 3 2006-02-07 22:50 jasong Miscellaneous Math 9 2005-09-10 23:34 fropones Math 2 2003-05-28 00:44

All times are UTC. The time now is 18:22.

Sun Nov 28 18:22:12 UTC 2021 up 128 days, 12:51, 0 users, load averages: 1.53, 1.36, 1.27