mersenneforum.org (https://www.mersenneforum.org/index.php)
-   Lone Mersenne Hunters (https://www.mersenneforum.org/forumdisplay.php?f=12)
-   -   Found a factor? Post it here. (https://www.mersenneforum.org/showthread.php?t=13977)

 James Heinrich 2022-05-28 14:40

[QUOTE=charybdis;606708]I see that Paul's list still hasn't ben updated. Did the code work correctly?[/QUOTE]It did, the email was sent, perhaps he's on vacation or something?

 charybdis 2022-05-31 02:06

[QUOTE=James Heinrich;606709]It did, the email was sent, perhaps he's on vacation or something?[/QUOTE]

Well there's a factor from 27 May on his top-10 ECM page for this year. Maybe he needs a nudge.

 James Heinrich 2022-05-31 02:08

[QUOTE=charybdis;606854]Well there's a factor from 27 May on his top-10 ECM page for this year. Maybe he needs a nudge.[/QUOTE]I talked to him earlier today, I imagine he will get the page updated sometime over the next few days.

 James Heinrich 2022-05-31 17:13

[QUOTE=James Heinrich;606855]I talked to him earlier today, I imagine he will get the page updated sometime over the next few days.[/QUOTE]He replied:[quote=Paul Zimmerman]for some reason I missed that report. It is now #10 on the list.
[url]https://members.loria.fr/PZimmermann/records/Pminus1.html[/url][/quote]

 Jwb52z 2022-06-05 02:16

P-1 found a factor in stage #1, B1=494000.
UID: Jwb52z/Clay, M115693873 has a factor: 1952359233750913828524289 (P-1, B1=494000)

80.691 bits.

 Denial140 2022-06-08 15:42

I've been running large P-1 on 4.96M to 4.97M without much luck (3 factors in 84 attempts, P-1 calculator predicts 12% increase in factor probability), with a success this morning! M4963463 has factor 740152403849563084825547533175743, 109.190 bits.

I've wondered whether these dry streaks are just bad luck, or if there is something wrong with my machine. I ran some P-1 tests that had previously found factors and all factors were found again, so I would expect not (maybe something tends to go wrong in the longer runs but not in the shorter ones?) Does anyone have any suggestions/ideas for how better to test?

 Batalov 2022-06-08 18:47

[QUOTE=Denial140;607349]I've wondered whether these dry streaks are just bad luck, or if there is something wrong with my machine.

Does anyone have any suggestions/ideas for how better to test?[/QUOTE]
The first question is valid, and the answer is - yes, both are possible.

Consider this analogy:
"I buy lottery tickets, fill in six numbers, and then scan them, and then wait to win. Sometimes I win twice in a row, and sometimes I have weeks and weeks without a win.
I've wondered whether these dry streaks are just bad luck, or if there is something wrong with my filling the tickets. Maybe my pen is broken, maybe I not filling the bubbles completely so that the lottery scanner cannot read them?"
Sure - both are possible.
Re: luck - Same as the poisson process of drawing a card from a deck and expect an ace. Sometimes you will draw two aces in a row, maybe even three, and sometimes you can draw 50 times and not get an ace.

For the second question - follow the analogy. Is there a better way to win in a lottery? Just like with the lottery, there are trivial solutions, for example with unlimited money buy _all_ the tickets, you will be guaranteed to win. Impractical though.

 Denial140 2022-06-08 19:20

[QUOTE=Batalov;607362]For the second question - follow the analogy. Is there a better way to win in a lottery? Just like with the lottery, there are trivial solutions, for example with unlimited money buy _all_ the tickets, you will be guaranteed to win. Impractical though.[/QUOTE]

Sorry, I was not clear - I mean specifically testing for machine errors without taking too long.

 Batalov 2022-06-08 20:47

Ah. Run the stability test (a.k.a. torture) - it is built in the program. Many folks run it once they have just built a new machine, for 24 - 48+ hours (best to run for several ambient temperature cycles - day/night. continuously). The key is - the code [I]knows [/I]the true answer so it can compare. *

It is hard to test otherwise (when answer is unknown).

____
* that actually reminded me to run that too, - summer is here. It is good to run the torture test at least once a year, too.

 BudgieJane 2022-06-14 09:15

[QUOTE=Batalov;607362]
For the second question - follow the analogy. Is there a better way to win in a lottery? Just like with the lottery, there are trivial solutions, for example with unlimited money buy _all_ the tickets, you will be guaranteed to win. Impractical though.[/QUOTE]

The best way to win the lottery is not to buy any tickets. That way you don't lose, and since the opposite of a loss is a win ...

 linament 2022-06-20 04:27

Two composite factors in a single day

I didn't think I was ever going to get a P-1 factor that I thought was worthy of posting here; but, today (PDT), I found [M]8879293[/M] has a composite factor, 1952505446389508559973390809501412786062062585404808923663962210457688947228452593 (270.042 bits):
[URL="https://www.mersenne.ca/factor/509948624278384111727110637486537527543"]509948624278384111727110637486537527543[/URL] (128.584 bits) and [URL="https://www.mersenne.ca/factor/3828827755251720703479206898096918957995351"]3828827755251720703479206898096918957995351[/URL] (141.458 bits)
Also found today, but slightly less impressive, I found [M]8859827[/M] has a composite factor, 35645538757884671884030612032344482636735761042071 (164.608 bits):
[URL="https://www.mersenne.ca/factor/39185475778814976961751"]39185475778814976961751[/URL] (75.053 bits) and [URL="https://www.mersenne.ca/factor/909662012504027897396320321"]909662012504027897396320321[/URL] (89.565 bits)
My first ever double composite in a single day.

All times are UTC. The time now is 16:33.