Any interest in some low n ECM factoring?

[Citrix]

1 curve on 265711*2^1344+1 with b1-1M and b2=1g

took 2 min for step 1
took 5 min for step 2


Also did p-1 with the same bounds, ecm seemed faster to me

[ltd]

The first 4 pairs are P-1 tested with B1=260000000.
The other 9 pairs are P-1 tested with B1=110000000.

What error did you get when you try to run the ECM binaries?

Lars

[Citrix]

It doesn't do anything. Not sure how to get them to work.

[ltd]

What did you use as comandline to run it?

For example i use:

ecm-p4.exe -nn -one -c 360 1000000 <input.txt >output.txt

The meaning of that is:

-nn run with lowest priority
-one stop working on a line when a factor is found
-c 360 run 360 curves
100000 B1 value
input.txt File containing the number you want to factor, can be: 265711*2^1344+1

output.txt all the results

There is no screen output when you specify an output file.
But you should run with the output file as there is no other way to store a factor found. ( At least i don't know any)
You can use
-v to get more output

Hope that helps,

Lars

[Mystwalker]

I currently run ECM on SoB's smallest k/n pairs (except 24737*2^991+1, which is on the way to 50 digits) for the 35 digit level.
When I'm done with those, I'll help.

[OmbooHankvald]

Hmm... When I run "ecm -one -c 950 100000 <input.txt >output.txt it spits out

"GMP-ECM 6.0.1 [powered by GMP 4.1.4] [ECM]
Input number is 79817*2^1191+1 (364 digits)
Using B1=100000, B2=31565865, polynomial x^2, sigma=2327328053
Step 1 took 17227ms
Step 2 took 6389ms"

...and stops working! How do I make it take more curves?

[patrik]

Try to make sure that input.txt is terminated with CR+LF or LF (e.g. put an empty line after the line). I remember some problems with version 5 of ECM under Windows being discussed half a year ago. Maybe they weren't fixed in version 6.

[Citrix]

Which number do you think will we find a factor for first? Which number of the above has the smallest factor. Place your guesses below.

Citrix

@ltd, will the factors if any found appear in output.txt? or where?

[OmbooHankvald]

Hopefully mine

And according to Zimmermans page:
Q1: How does one recognize a new factor was found?
A1: Some lines as follows appear in the output file:

********** Factor found in step 2: 15697920117275073486338469567634384633
Found probable prime factor of 38 digits: 15697920117275073486338469567634384633
Probable prime cofactor 248224208600891230638840397209907041348178075109876163768459663055209916421778767469609238164044706325366885940218654867062058537 has 129 digits