[QUOTE=henryzz;281369]Doesn't p-1 stage 2 use ffts. Surely they stand a chance of errors just like ll tests.[/QUOTE]

Both stages (1 & 2) use FFT.

However much fewer FFT muls are involved compared to the LL test. So overall chance of error per test is lower.

Additionally, unlike LL, errors that occur in Stage 2 (and to a lesser extent, Stage 1) _need not_ prevent the finding of the factor.

Certainly not enough errors to get bad results for as many exponents as JH has found (if that's what you were referring to...)

[QUOTE=Dubslow;281432]Certainly not enough errors to get bad results for as many exponents as JH has found (if that's what you were referring to...)[/QUOTE]

Check out [URL]http://mersenne-aries.sili.net/exponent.php?exponentdetails=7012963[/URL], not only did the original P-1 fail to find it, the TF also failed.

Today marks the point where I've found 730 P-1 factors in the [url=http://v5www.mersenne.org/report_top_500_P-1/]last 365 days[/url], so I've reached the 2-per-day mark. :smile:

Out of 19,248 tests and 5,939.7 GHz-days, that's 3.79% success ratio (explained by the fact that most of the work I've been doing the last year is re-doing work that was done with a ~2% factor chance instead of the normal ~5%), and 8.136GHz-days per factor.

Huzzah, James! Huzzah!

[QUOTE=James Heinrich;281601]Today marks the point where I've found 730 P-1 factors in the [url=http://v5www.mersenne.org/report_top_500_P-1/]last 365 days[/url], so I've reached the 2-per-day mark. :smile:[/QUOTE]
Nice work, James! :toot: :bow:

[QUOTE=bcp19;281434]Check out [URL]http://mersenne-aries.sili.net/exponent.php?exponentdetails=7012963[/URL], not only did the original P-1 fail to find it, the TF also failed.[/QUOTE]
That reminded me of a [I]very[/I] old thread about [URL="http://www.mersenneforum.org/showthread.php?t=1425"]missed small factors[/URL]. Back then, 7.019M to 7.06M (and other ranges) was found to have factors that trial factoring missed first time around.

I've started checking 7.0M to 7.019M - one found so far, a 55 bit factor of M7013393, the same size as for M7012963. :coffee:

[QUOTE=James Heinrich;281601]Today marks the point where I've found 730 P-1 factors in the [url=http://v5www.mersenne.org/report_top_500_P-1/]last 365 days[/url], so I've reached the 2-per-day mark. :smile:

Out of 19,248 tests and 5,939.7 GHz-days, that's 3.79% success ratio (explained by the fact that most of the work I've been doing the last year is re-doing work that was done with a ~2% factor chance instead of the normal ~5%), and 8.136GHz-days per factor.[/QUOTE]


Wow, congrats!!

Congratulations, Mr. Heinrich!

[QUOTE=James Heinrich;279291]To list those exponents (that I've found so far) in one place for easy reference:[/QUOTE]
3 more:
[url=http://mersenne-aries.sili.net/6802123]M6,802,123[/url], [url=http://mersenne-aries.sili.net/6853937]M6,853,937[/url], [url=http://mersenne-aries.sili.net/6853967]M6,853,967[/url], [url=http://mersenne-aries.sili.net/6854297]M6,854,297[/url], [url=http://mersenne-aries.sili.net/6888719]M6,888,719[/url], [url=http://mersenne-aries.sili.net/6935129]M6,935,129[/url], [url=http://mersenne-aries.sili.net/6937501]M6,937,501[/url], [b][url=http://mersenne-aries.sili.net/6961751]M6,961,751[/url][/b], [b][url=http://mersenne-aries.sili.net/6984797]M6,984,797[/url][/b], [i][url=http://mersenne-aries.sili.net/7012963]M7,012,963[/url][/i], [b][url=http://mersenne-aries.sili.net/8289409]M8,289,409[/url][/b], [url=http://mersenne-aries.sili.net/8855257]M8,855,257[/url]

[QUOTE=markr;281723][QUOTE=bcp19;281434]Check out [URL]http://mersenne-aries.sili.net/exponent.php?exponentdetails=7012963[/URL], not only did the original P-1 fail to find it, the TF also failed.[/QUOTE]
That reminded me of a [I]very[/I] old thread about [URL="http://www.mersenneforum.org/showthread.php?t=1425"]missed small factors[/URL]. Back then, 7.019M to 7.06M (and other ranges) was found to have factors that trial factoring missed first time around.

I've started checking 7.0M to 7.019M - one found so far, a 55 bit factor of [URL="http://mersenne-aries.sili.net/exponent.php?exponentdetails=7013393"]M7013393[/URL], the same size as for M7012963. :coffee:[/QUOTE]
7.0M to 7.019M is now checked to 2^59, and I'll take it to 2^60.

[URL="http://mersenne-aries.sili.net/exponent.php?exponentdetails=7018901"]M7018901[/URL] has a 58 bit factor. It was assigned to Carsten Kossendey for P-1 (since March): I don't usually poach but since P-1 would be very unlikely to find a factor with k = 43 x 258029413 I hope he won't mind too much.