[Ecm-discuss] GMP-ECM finds input N

Paul Zimmermann Paul.Zimmermann at loria.fr
Lun 30 Mar 18:02:37 CEST 2009


       Alex,

> You could also do runs with "residue verboseness," enabled by adding "-v 
> -v" to the command line. That way GMP-ECM prints the residue after stage 
> 1, and the product of the polynomials values at the end of stage 2.

good suggestion. Note however that the problem happens after only a few
iterations in stage 1.

Sam, I did complete the two runs you gave as example, but unfortunately
did not find any factor:

GMP-ECM 6.1.3 [powered by GMP 4.2.2] [ECM]
Input number is 278490841076279407188741439481565179355926725853710201632331620642982062389901741890579963524423782637435949041666525000702723914662388812510545494307250950777886431051612811386531 (180 digits)
Using B1=250000000, B2=3178548473116, polynomial Dickson(30), sigma=4289042661
Step 1 took 1857826ms
Step 2 took 746444ms

GMP-ECM 6.1.3 [powered by GMP 4.2.2] [ECM]
Input number is 14934281803738074833846530939409385751024026044300465118534154673896853000327668729857703720112054704958367178027970628991322333492709062468099971107486071617412384700105582187783796209467840083368845344499411394764018753571730339338183895417675798252986998481786698140379322970784655881751945808698842016800757 (311 digits)
Using B1=250000000, B2=3178548473116, polynomial Dickson(30), sigma=4254596094
Step 1 took 4466454ms
Step 2 took 1311246ms

Paul




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