Thank you. I'll try to remember from now on so I won't do that again.

Found a nice 102 bit factor: [URL]http://mersenne-aries.sili.net/exponent.php?exponentdetails=8491921[/URL], was just missed by the old P-1

[QUOTE=Jwb52z;304610]Thank you. I'll try to remember from now on so I won't do that again.[/QUOTE]

Speaking only for myself, such reports are interesting wherever they turn up.

Found another B-S factor [URL]http://mersenne-aries.sili.net/exponent.php?exponentdetails=8499577[/URL]

When searching for big P-1 factors do I necessarily need to use high B1/B2 bounds? I can get big factors when k is a product of a bunch of small primes, right?
Does the probability of finding a big factor increase by using higher bounds?

[QUOTE=MrHappy;308249]Does the probability of finding a big factor increase by using higher bounds?[/QUOTE]The probability of finding a factor of any kind increases with higher bounds. You are correct that it is possible to find large factors with small bounds ([url=http://mersenne-aries.sili.net/M31001941]M31001941[/url] and [url=http://mersenne-aries.sili.net/M11865241]M11865241[/url] are some more extreme examples of this). Your probability of finding [i]any[/i] factor should be somewhere around 5% for a P-1 test, but whether you find a 130-bit monster or a 73.01-bit one that just missed TF is out of your control.

I would advise [i]against[/i] choosing artificially small bounds (or manually choosing bounds at all unless you're [i]very[/i] certain what you're doing) in hopes of finding large factors with small bounds. If such a small factor exists, P-1 will likely find it in stage1 anyways, saving you half a P-1 test.

Is it true that any factor found in stage 1 would always be found in stage 2 also?

[QUOTE=flashjh;308365]Is it true that any factor found in stage 1 would always be found in stage 2 also?[/QUOTE]

Yes, though the only way this would happen is if you skip the Stage 1 GCD.

[QUOTE=Dubslow;308366]Yes, though the only way this would happen is if you skip the Stage 1 GCD.[/QUOTE]
I'm just looking at how much time all my systems spend in S1 vs S2. I know S2 is slower, but I think the time wasted in S1 when no factor is found would generally be made up by just running S2 and finding the factors anyway.

I know it has been discussed before, but what would be required to get future versions of P95 to just do S2 on all P-1, as an option? In a project like GPU72 (and many others, I'm sure), P-1 is [I]always*[/I] done with enough memory, so skipping S1 would save me time. Just a thought...

* Not true, but it sounds great

[QUOTE=flashjh;308368]I'm just looking at how much time all my systems spend in S1 vs S2. I know S2 is slower, but I think the time wasted in S1 when no factor is found would generally be made up by just running S2 and finding the factors anyway.

I know it has been discussed before, but what would be required to get future versions of P95 to just do S2 on all P-1, as an option? In a project like GPU72 (and many others, I'm sure), P-1 is [I]always*[/I] done with enough memory, so skipping S1 would save me time. Just a thought...

* Not true, but it sounds great[/QUOTE]

Oh, I thought you meant doing the S1 work without checking for a factor. I don't think you can do S2 without S1, which is why changing S1 bounds means you toss any S2 work you had. (Edit: More proof is that you need the full S1 save file to run S2.)

[QUOTE=Dubslow;308370]Oh, I thought you meant doing the S1 work without checking for a factor. I don't think you can do S2 without S1, which is why changing S1 bounds means you toss any S2 work you had. (Edit: More proof is that you need the full S1 save file to run S2.)[/QUOTE]
Right, but is that a necessary thing or a legacy of systems running P-1 with 8Mb years ago? So S1 generates necessary data for S2 that can not be computed before hand? Based on what I have read so far, I could only find what you said, that without the save file, P95 won't run S2.