Group order not accepted for some GMP-ECM factors?

rwwh · 2015-06-19, 05:48

I normally upload any factorizations I find using GMP-ECM to factordb. Once in a while it does not want to accept the ECM report and tells me to check the results because the group order does not fit B1/B2.

Does this have anything to do with the Brent-Suyama's extension? And is there anything I should do to make sure the ECM results are accepted?

Batalov · 2015-06-19, 06:10

One easy trick to do is add an extra zero to B2; it will most likely be accepted then.

axn · 2015-06-19, 06:26

Factordb itself has a group order calculator (http://www.factordb.com/groupcalc.php). You can use that to check if that is the issue, and the fudge B2 (and/or B1) accordingly.

2015-06-19, 05:48	#1
rwwh "Rob Hooft" Jun 2015 Netherlands 1 Posts	Group order not accepted for some GMP-ECM factors? I normally upload any factorizations I find using GMP-ECM to factordb. Once in a while it does not want to accept the ECM report and tells me to check the results because the group order does not fit B1/B2. Does this have anything to do with the Brent-Suyama's extension? And is there anything I should do to make sure the ECM results are accepted?

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2015-06-19, 06:10	#2
Batalov "Serge" Mar 2008 Phi(4,2^7658614+1)/2 2749₁₆ Posts	One easy trick to do is add an extra zero to B2; it will most likely be accepted then.

2015-06-19, 06:26	#3
axn Jun 2003 2²×3²×151 Posts	Factordb itself has a group order calculator (http://www.factordb.com/groupcalc.php). You can use that to check if that is the issue, and the fudge B2 (and/or B1) accordingly.