From Prime-Wiki
Jump to: navigation, search
Gimps.gif This article is only a stub. You can help PrimeWiki by expanding it.

AdvancedFactor is one of the undocumented options for Prime95, which was removed in later versions. The format for the line you add to the worktodo.ini file is:

AdvancedFactor=start_exponent, end_exponent, b1, b2


start_exponent is the first exponent in a range to test.
end_exponent is the last exponent in a range to test.
b1 is the starting bit-depth to test with.
b2 is the ending bit-depth to test with.

The line:

AdvancedFactor=1000000, 2000000, 64, 68

would attempt to trial-factor every prime exponent between 1,000,000 and 2,000,000 for factors between 264 and 268.

If you don't want to check a range of exponents, and instead just want to check a specific set of exponents, you need to use the line in worktodo.ini:

Factor=exp, bd


exp is the exponent to trail-factor.
bd is where to begin trial-factoring at (2bd).

The line:

Factor=42099977, 61

would attempt to trial-factor the exponent 42,099,977 starting at 261 and continue until it either found a factor or reached 269 (Prime95's default breakpoint for this exponent), unless you used the FactorOverride line in prime.ini.

If you put say:


in prime.ini, Prime95 would attempt to factor it only up to 266 instead of 269.

You would have to put a Factor= line in worktodo.ini for each and every exponent you wanted to test.

If you are using the most recent version of Prime95, v24.14, it will accept exponents to trial-factor up to 2 Billion. While none of the documentation says specifically, looking at the source code, it would appear that Prime95 can do SSE2 factoring up to 286 and non-SSE2 factoring up to 296.