mersenneforum.org  

Go Back   mersenneforum.org > Great Internet Mersenne Prime Search > Data > mersenne.ca

Reply
 
Thread Tools
Old 2021-03-13, 14:35   #551
James Heinrich
 
James Heinrich's Avatar
 
"James Heinrich"
May 2004
ex-Northern Ontario

25·3·5·7 Posts
Default

Quote:
Originally Posted by Viliam Furik View Post
it's more important for a table to have correct data than to look pretty.
However in this case, it both looks ugly and probably contains a good deal of incorrect data.

Also, the URL has changed to https://www.mersenne.ca/factored_counts_report_tf/

Last fiddled with by James Heinrich on 2021-03-13 at 15:12
James Heinrich is offline   Reply With Quote
Old 2021-03-13, 15:38   #552
Viliam Furik
 
"Viliam Furík"
Jul 2018
Martin, Slovakia

23·3·19 Posts
Default

Quote:
Originally Posted by James Heinrich View Post
However in this case, it both looks ugly and probably contains a good deal of incorrect data.

Also, the URL has changed to https://www.mersenne.ca/factored_counts_report_tf/
You may be right about the incorrect data. In the 999M range, there are supposed to be 27515 factored exponents, however, the table row sums to only about 500.

Is it possible, that your query ignores the ones with factors less than 67, instead of making them appear like they are TFed to 67, and thus not making the 67 range be <=67?
Viliam Furik is online now   Reply With Quote
Old 2021-03-13, 15:45   #553
masser
 
masser's Avatar
 
Jul 2003
wear a mask

1,609 Posts
Default

Quote:
Originally Posted by Viliam Furik View Post
Yes, that's what I am looking for.

I think the problem with no TF data can be solved by trusting the user TJAOI, that there are no more factors under 67 bits (technically he is at 66.990, but in a week or two he is done). Maybe some check-box "I trust TJAOI" could be made, such that when checked, considers all exponents to be TFed to at least 67 bits (or the current TJAOI-TF integer bit-level achieved), and when not, takes what is in the database. Or no check-box with a disclaimer that data is based on TJAOI's work.

Are you planning to TF some exponents that have known factors to higher bit levels? Besides TJAOI's efforts, you should also keep in mind the P-1 bounds (if you trust them; there are reasons why you might not) will occasionally make TF irrelevant at lower bit levels. For the very low exponents (say, < 3M or so), ECM makes additional TF even more non-productive.

Last fiddled with by masser on 2021-03-13 at 15:45
masser is online now   Reply With Quote
Old 2021-03-13, 16:53   #554
James Heinrich
 
James Heinrich's Avatar
 
"James Heinrich"
May 2004
ex-Northern Ontario

25·3·5·7 Posts
Default

Quote:
Originally Posted by Viliam Furik View Post
For the P-1, yes, that is pretty much what I imagined.
Now available at https://www.mersenne.ca/factored_counts_report_pm1/ with separate reports for factored and unfactored exponents.

You can again access the latest report via
https://www.mersenne.ca/factored_cou..._pm1/?latest=f and/or
https://www.mersenne.ca/factored_cou..._pm1/?latest=n respectively.


Quote:
Originally Posted by Viliam Furik View Post
You may be right about the incorrect data. In the 999M range, there are supposed to be 27515 factored exponents, however, the table row sums to only about 500.
I will investigate this.
James Heinrich is offline   Reply With Quote
Old 2021-03-13, 18:25   #555
Viliam Furik
 
"Viliam Furík"
Jul 2018
Martin, Slovakia

45610 Posts
Default

Quote:
Originally Posted by masser View Post
Are you planning to TF some exponents that have known factors to higher bit levels?
Yes, mostly the easy-to-do ones (for me that's <10 GHz-D).

Quote:
Originally Posted by masser View Post
Besides TJAOI's efforts, you should also keep in mind the P-1 bounds (if you trust them; there are reasons why you might not) will occasionally make TF irrelevant at lower bit levels.
Yes, I know. From my experience with factoring of the 10M range, I know that about half of the factors are easier to find by TF than P-1 if we compare the two methods. The other half is easier to find by P-1. Easy is defined by the GHz-D amount.

The ratio is most probably not 1:1, but close enough, I would say.

Quote:
Originally Posted by masser View Post
For the very low exponents (say, < 3M or so), ECM makes additional TF even more non-productive.
In this range, there are not many TFable exponents that fit my work criterion. I also have this weird uncomfortability with ECM, because I don't have a complete idea of how it works, only a rough idea.
Viliam Furik is online now   Reply With Quote
Old 2021-03-13, 18:49   #556
petrw1
1976 Toyota Corona years forever!
 
petrw1's Avatar
 
"Wayne"
Nov 2006
Saskatchewan, Canada

10010000110112 Posts
Default

Quote:
Originally Posted by Viliam Furik View Post
Yes, I know. From my experience with factoring of the 10M range, I know that about half of the factors are easier to find by TF than P-1 if we compare the two methods. The other half is easier to find by P-1. Easy is defined by the GHz-D amount.

The ratio is most probably not 1:1, but close enough, I would say.
Some stats:
Top 500 totals in each of TF, P1 and ECM.
Interestingly the last column (GhzDays/Factor) does NOT vary a whole lot.

Code:
Work   GhzDays   Attempts    Succ.   GD/Att   GD/Succ
TF   134655501   34272856   710178     3.93    189.61
P1      790280     114778     3811     6.89    207.37
ECM     181452     356771     1150     0.51    157.78
petrw1 is online now   Reply With Quote
Old 2021-03-13, 19:01   #557
James Heinrich
 
James Heinrich's Avatar
 
"James Heinrich"
May 2004
ex-Northern Ontario

1101001000002 Posts
Default

Quote:
Originally Posted by Viliam Furik View Post
I also have this weird uncomfortability with ECM, because I don't have a complete idea of how it works, only a rough idea.
A (very) rough analogy is the game Battleship -- you guess a random square/curve and see if it hits something. The more attempts you make in a particular area the more likely you are to find something hiding there. You might get lucky and get a hit on your very first attempt, there's also a chance you could use all your guesses and miss every one. Overall it allows finding factors larger than is practical for TF and that don't fit the rules for being found by P-1.
James Heinrich is offline   Reply With Quote
Old 2021-03-13, 19:06   #558
Viliam Furik
 
"Viliam Furík"
Jul 2018
Martin, Slovakia

23×3×19 Posts
Default

Quote:
Originally Posted by petrw1 View Post
Interestingly the last column (GhzDays/Factor) does NOT vary a whole lot.
If I am interpreting the numbers correctly, that means I am about right. Is that correct?

Maybe the best way to test would be to parse the list of known factors and compare the minimal work amount for TF and P-1, as there is a bias towards the TF in the factoring process because the TF is done first.
Viliam Furik is online now   Reply With Quote
Old 2021-03-13, 19:09   #559
Viliam Furik
 
"Viliam Furík"
Jul 2018
Martin, Slovakia

23×3×19 Posts
Default

Quote:
Originally Posted by James Heinrich View Post
A (very) rough analogy is the game Battleship -- you guess a random square/curve and see if it hits something. The more attempts you make in a particular area the more likely you are to find something hiding there. You might get lucky and get a hit on your very first attempt, there's also a chance you could use all your guesses and miss every one. Overall it allows finding factors larger than is practical for TF and that don't fit the rules for being found by P-1.
That I understand, but the part not clear to me is how do the bounds affect the outcome of the ECM, and how exactly is the factor found by the elliptic curve.

Bounds in the P-1 are pretty straightforward, but because ECM is based on chance, the straightforwardness goes away.
Viliam Furik is online now   Reply With Quote
Old 2021-03-13, 19:16   #560
James Heinrich
 
James Heinrich's Avatar
 
"James Heinrich"
May 2004
ex-Northern Ontario

25×3×5×7 Posts
Default

Quote:
Originally Posted by Viliam Furik View Post
You may be right about the incorrect data. In the 999M range, there are supposed to be 27515 factored exponents, however, the table row sums to only about 500.
The bulk of the exponents in the upper ranges have known factors but no record of what factoring effort was done (makes sense, the small factors are trivial to find) so the field that tracks factoring on factored exponents wasn't set. I've set them all now to the assumption that TJAOI has found everything up to 267 (right now he's working between 66.987 and 66.990 so I'm jumping the gun slightly).
James Heinrich is offline   Reply With Quote
Old 2021-03-13, 20:04   #561
VBCurtis
 
VBCurtis's Avatar
 
"Curtis"
Feb 2005
Riverside, CA

112538 Posts
Default

Quote:
Originally Posted by Viliam Furik View Post
That I understand, but the part not clear to me is how do the bounds affect the outcome of the ECM, and how exactly is the factor found by the elliptic curve.

Bounds in the P-1 are pretty straightforward, but because ECM is based on chance, the straightforwardness goes away.
While I cannot speak to the "how is the factor found", I find it helpful to think of ECM as similar to P-1, except that ECM is sort of checking P - sigma (where sigma is the random seed). The effect of bounds on ECM and P-1 are just about the same. This is, to be sure, more analogy than mathematically-accurate representation.
VBCurtis is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Small inconsistencies between mersenne.org and mersenne.ca factor databases GP2 mersenne.ca 44 2016-06-19 19:29
mersenne.ca (ex mersenne-aries.sili.net) LaurV mersenne.ca 8 2013-11-25 21:01
Gaussian-Mersenne & Eisenstein-Mersenne primes siegert81 Math 2 2011-09-19 17:36
Mersenne Wiki: Improving the mersenne primes web site by FOSS methods optim PrimeNet 13 2004-07-09 13:51

All times are UTC. The time now is 14:54.

Tue May 11 14:54:01 UTC 2021 up 33 days, 9:34, 1 user, load averages: 3.06, 2.72, 2.53

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.

This forum has received and complied with 0 (zero) government requests for information.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.
A copy of the license is included in the FAQ.