P-1 Stage 2

[dave_0273]

I don't really know if this is in the right place, so feel free to move it if it isn't.

I was wondering if there was any way that just stage 2 of p-1 factoring can be repeated. A lot of exponents have had stage 1 done, but little or no stage 2. Is there any way of picking up where they left off, by just doing stage 2???

[nuutti]

Originally Posted by dave_0273

I don't really know if this is in the right place, so feel free to move it if it isn't.

I was wondering if there was any way that just stage 2 of p-1 factoring can be repeated. A lot of exponents have had stage 1 done, but little or no stage 2. Is there any way of picking up where they left off, by just doing stage 2???

I think that you need savefile from person who did original p-1 factoring.
So answers is practically no.

nuutti

[ET_]

IIRC, stage 2 depends on bounds defined in stage 1, but low or no information is given on which bound has been used on each P-1 test.

Luigi

[dave_0273]

Wouldn't it just be B1 - and that can be found in pminus1.txt that comes out in the weekly files??

[nfortino]

Originally Posted by dave_0273

Wouldn't it just be B1 - and that can be found in pminus1.txt that comes out in the weekly files??

As described on the math page http://www.mersenne.org/math.htm, stage 1 calculates 3 raised to a large power mod the Mersenne number. Stage 2 requires this residue to work.