Running ECM on YAFU

[ThomRuley]

I just started using YAFU to run ECM on large composites for the OPN search. I really like the speed but I did have one question. While looking through the available flags the readme file said I could set the B1 and B2 values as desired. I tried to set the B1 to 50K after stopping a factorization in YAFU, and then tried to restart at the 50K B1 bound using

yafu "factor(number)" -B1ecm 50000

The program started from the very beginning of the factorization, repeating all the earlier steps. Is there a way to get YAFU to start at say, ECM with a B1 of 50K?

Thanks

[swellman]

Originally Posted by ThomRuley

I just started using YAFU to run ECM on large composites for the OPN search. I really like the speed but I did have one question. While looking through the available flags the readme file said I could set the B1 and B2 values as desired. I tried to set the B1 to 50K after stopping a factorization in YAFU, and then tried to restart at the 50K B1 bound using

yafu "factor(number)" -B1ecm 50000

The program started from the very beginning of the factorization, repeating all the earlier steps. Is there a way to get YAFU to start at say, ECM with a B1 of 50K?

Thanks

Try

yafu “ecm(number, # of curves)” -v -B1ecm 50000

Also note that you can perform ECM multithreaded with yafu - open yafu.ini, change the value of “threads=“ to however many threads you want to run in parallel, save and close yafu.ini. Then use the above invocation line.

[ThomRuley]

Thanks, the speed on these curves is amazing.

[swellman]

If you want to makes things more seamless, try WraithX’s python scrpit for GMP-ECM. You can find the latest release in post 109 of this thread:

https://www.mersenneforum.org/showth...=15508&page=10

You need to install Python 2 and 3 on your system before running it - Google for the download/setup of both python versions.

[ThomRuley]

Originally Posted by swellman

If you want to makes things more seamless, try WraithX’s python scrpit for GMP-ECM. You can find the latest release in post 109 of this thread:

https://www.mersenneforum.org/showth...=15508&page=10

You need to install Python 2 and 3 on your system before running it - Google for the download/setup of both python versions.

Do I need the GMP-ECM files first? I've been having a heck of a time trying to find a working copy of those files.

[swellman]

Originally Posted by ThomRuley

Do I need the GMP-ECM files first? I've been having a heck of a time trying to find a working copy of those files.

If you can run ECM on Yafu then you must already have ecm.exe on your system - look in the yafu.ini file to see where Yafu grabs the executable file when you call the ECM() function.

You can copy and move the standalone ecm.exe to wherever you set up the python script for GMP-ECM. It’s a small self-contained file in Windows.

[ThomRuley]

How much of a speed improvement would it be to move from yafu to gmp-ecm?

[swellman]

Not much change in speed but you can stop/resume work, use batch input files with more ease, etc

[VBCurtis]

Originally Posted by ThomRuley

How much of a speed improvement would it be to move from yafu to gmp-ecm?

Yafu is using GMP-ECM, so none.
Yafu is just a convenient wrapper to call the ecm.exe program, which is GMP-ECM.

[EdH]

YAFU 1 had a built-in version of ECM that was used if GMP-ECM wasn't found. Does YAFU 2 have the same? If so, the package GMP-ECM may not actually be being called. YAFU 1 used to tell you if it didn't find the GMP-ECM version. Is any such message being displayed?

And, if YAFU 2 doesn't have the built-in ECM anymore, I'd like to know that, as well.

[ThomRuley]

Originally Posted by EdH

YAFU 1 had a built-in version of ECM that was used if GMP-ECM wasn't found. Does YAFU 2 have the same? If so, the package GMP-ECM may not actually be being called. YAFU 1 used to tell you if it didn't find the GMP-ECM version. Is any such message being displayed?

And, if YAFU 2 doesn't have the built-in ECM anymore, I'd like to know that, as well.

It appears that Yafu 2 also has its own built-in version of ecm. While yafu has been running ecm curves (quite nicely I might add), I did a search of my entire hard drive for a separate ecm executable file. Nothing came up on the search. Also, the paths I found in yafu.ini led to nowhere and did not seem to affect the ECM.