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-   -   fond of a factor? Urn yourself to become remains (https://www.mersenneforum.org/showthread.php?t=13977)

ric 2018-10-07 13:26

phoned a factor...
 
... and I got this pretty one:
[CODE]UID: RU/Nomad2C, M12103879 has a factor: 76589819640254233618412004377777346859019502009144302474620595280120616202419586537 (P-1, B1=430000, B2=8500000, E=12)
[/CODE]

275 bits, composite (84 + 90 + 103). As a side note, had to resort to manual page submission in order to have it processed (CURL raised a timeout in automatic processing and stopped the queue).

James Heinrich 2018-10-07 13:35

[QUOTE=ric;497563]275 bits, composite (84 + 90 + 103)[/QUOTE]That is pretty! :bow:

Jwb52z 2018-10-08 05:08

P-1 found a factor in stage #2, B1=715000, B2=13048750.
UID: Jwb52z/Clay, M89067427 has a factor: 524395562032803866876089 (P-1, B1=715000, B2=13048750),

78.795 bits.

GP2 2018-10-08 05:30

[QUOTE=ric;497563]275 bits, composite (84 + 90 + 103). As a side note, had to resort to manual page submission in order to have it processed (CURL raised a timeout in automatic processing and stopped the queue).[/QUOTE]

So what would have happened if you didn't manually intervene? The factor would have been dropped and lost?

And how often has that actually happened, to other people, and no one the wiser?

ric 2018-10-08 10:02

An interesting observation: here's my thinking

[QUOTE=GP2;497613] The factor would have been dropped and lost?[/QUOTE]

No.

[QUOTE=GP2;497613] So what would have happened if you didn't manually intervene?[/QUOTE]

I've opted to use Primenet to report results, so the large factor and all results following that one, they all stacked up into prime.spl (I saw this factor the day after its discovery, so this is a fact) - a message on screen [CODE]CURL library error: Operation timed out after 180000 milliseconds with 0 bytes received[/CODE] and an equivalent entry in prime.log warned that something weird was happening at each subsequent result/communication attempt - in all likelihood, with such visible warnings, even a novice user would have come to mersenneforum to ask for advice.

Had I opted for [B]not[/B] communicating directly to Primenet, the first subsequent manual submission would have lasted a bit longer than usual.

[QUOTE=GP2;497613] And how often has that actually happened, to other people, and no one the wiser?[/QUOTE]

IMAO P(x)->0 :smile:

Two side notes:[LIST=1][*]I've also pondered about asking to raise the 3 min threshold for CURL communication, but the low occurrence of these large factors IMO does not justify this measure[*]oh, and BTW I noticed that this factor does not appear in the "Recent Cleared" report, but again clipping the outliers to me is a sane measure[/LIST]
TL;DR: I like the way it is, and see no danger in it. Other opinions are welcome :smile:

James Heinrich 2018-10-08 12:15

I suspect that the original (automatic) submission triggered an attempt to factor the factor, which is non-trivial, and the communication timed out while waiting for the result of the factor factorization. By the time the manual communication was attempted, the original factor splitting was completed and cached so the manual communication went through immediately.

On a side note, my site now displays composite factors found as the list of the prime components for greater clarity:
[url]https://www.mersenne.ca/exponent/12103879[/url]
I also wonder why the original P-1, apparently done nearly 18 years ago, should have but didn't find two of the three factors?

ric 2018-10-08 13:51

[QUOTE=James Heinrich;497622]By the time the manual communication was attempted, the original factor splitting was completed and cached so the manual communication went through immediately.[/QUOTE]

It's likely, and my educated guess is that the "factor the factor" process was started during my initial manual submission (the large factor + subsequent no factor results), and completed - caching included - by the time I re-submitted the large factor alone (impatient? who, me? :smile:).

This guess of mine is based on the evidence that I have two identical result lines for it in my results report (crediting half a GHz-Day each, go figure!) and on mersenne.ca as well.

[QUOTE=James Heinrich;497622]I also wonder why the original P-1, apparently done nearly 18 years ago, should have but didn't find two of the three factors?[/QUOTE]

Not the first one of this kind, probably won't even be the last (another recent example: [URL="https://www.mersenne.ca/exponent/12076891"]M12076891[/URL] - incidentally, it has a glitch right now, preventing display).

I recall a discussion somewhere else on mersenneforum, with the general consensus that re-doing older P-1 was basically futile (and however mersenne.ca maintains [URL="https://www.mersenne.ca/p1missed.php"]this list[/URL]).

James Heinrich 2018-10-08 14:02

[QUOTE=ric;497627][URL="https://www.mersenne.ca/exponent/12076891"]M12076891[/URL] - incidentally, it has a glitch right now, preventing display[/QUOTE]Already fixed :smile:

ric 2018-10-09 09:11

[QUOTE=James Heinrich;497628]Already fixed :smile:[/QUOTE]

Amazing speed! Thx

Jwb52z 2018-10-23 22:26

P-1 found a factor in stage #2, B1=715000, B2=13227500.
UID: Jwb52z/Clay, M89267203 has a factor: 34165373881617506022060001 (P-1, B1=715000, B2=13227500),

84.821 bits.

Jwb52z 2018-10-27 20:37

P-1 found a factor in stage #1, B1=715000.
UID: Jwb52z/Clay, M89218183 has a factor: 1578944744818761269375521 (P-1, B1=715000),

80.385 bits.


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