Newer milestone thread

[Madpoo]

Originally Posted by retina

I'm not sure about the rounding used but I suppose at the most it could be 0.099999... days, i.e. just under 2.4 hours. Is such a time possible with current technology?

Moot point since I don't see that exponent being assigned to anyone else.

I've officially removed that little item from the progress section of the milestones page. Is it worth mentioning in the "older/lower profile milestones" section, that today is the day we finished all the 10M doublechecks? It was kind of interesting to see it countdown, but how important is that really?

I guess no more or less important than any other artificial milestone already listed, but you know what I mean.

[NBtarheel_33]

Originally Posted by Madpoo

Moot point since I don't see that exponent being assigned to anyone else.

I've officially removed that little item from the progress section of the milestones page. Is it worth mentioning in the "older/lower profile milestones" section, that today is the day we finished all the 10M doublechecks? It was kind of interesting to see it countdown, but how important is that really?

I guess no more or less important than any other artificial milestone already listed, but you know what I mean.

I think it is worth making a note of this for posterity. We already have listed the date on which we finished double-checking everything under one million digits. We also have listed the dates of the first successful ten-million-digit test and the completion of the last first-time test under ten million digits.

[Uncwilly]

Originally Posted by chalsall

20141115 33185861 D LL, 54.90% 143 26 2014-06-25 2014-11-14 2014-11-15 2014-12-11 nranks
20141123 33185861 D LL, 54.70% 151 27 2014-06-25 2014-11-23 2014-11-24 2014-12-20 nranks
20141210 33185861 D LL, 53.50% 168 28 2014-06-25 2014-12-09 2014-12-10 2015-01-07 nranks
20150101 33185861 D LL, 58.20% 221 18 2014-06-25 2015-01-30 2015-01-31 2015-02-19 nranks

Looks like the machine was having problems and went backwards.

[TheMawn]

Originally Posted by Uncwilly

Looks like the machine was having problems and went backwards.

It's too bad the user didn't figure out that if one starts at the final iteration and works backward, there isn't any need to go all the way to the very beginning.

[Madpoo]

Originally Posted by NBtarheel_33

I think it is worth making a note of this for posterity. We already have listed the date on which we finished double-checking everything under one million digits. We also have listed the dates of the first successful ten-million-digit test and the completion of the last first-time test under ten million digits.

True, I guess it can't hurt, since those other things are in there. Added.

I was torn between these two versions:
All exponents below 33,219,253 (10 million digits) double-checked.

or this:
All Mersenne numbers up to 10 million digits double-checked.

I left the first one there for now... it seems more precise and less likely to confuse, but I'm looking at it from my own perspective...not sure which is more readable for the average Joe.

[potonono]

Originally Posted by chalsall

This looks like it might very likely have been a legitimate "recycling" by Primenet, rather than a "poaching" (my spidering is not at a high enough temporal resolution to be able to say for sure).

20141115 33185861 D LL, 54.90% 143 26 2014-06-25 2014-11-14 2014-11-15 2014-12-11 nranks
20141123 33185861 D LL, 54.70% 151 27 2014-06-25 2014-11-23 2014-11-24 2014-12-20 nranks
20141210 33185861 D LL, 53.50% 168 28 2014-06-25 2014-12-09 2014-12-10 2015-01-07 nranks
20150101 33185861 D LL, 58.20% 221 18 2014-06-25 2015-01-30 2015-01-31 2015-02-19 nranks

Assigned to "nranks" under the new recycling rules (possibly as a "Cat 2"); gratiously given over 220 days to complete. Making very slow progress.

I have access to this machine. It makes slow progress due to being an Intel i5 M 520 @ 2.40GHz running two double checks, and only being on 8 to 9 hours a day. I am not aware of any hardware issues, as it has only returned good results. What would be a more appropriate work type if too slow for double checks? ECM? Some other project? Nothing?

[axn]

Originally Posted by potonono

I have access to this machine. It makes slow progress due to being an Intel i5 M 520 @ 2.40GHz running two double checks, and only being on 8 to 9 hours a day. I am not aware of any hardware issues, as it has only returned good results. What would be a more appropriate work type if too slow for double checks? ECM? Some other project? Nothing?

Have a look at http://www.mersenne.org/thresholds/. Are you receiving assignments from an inappropriate category? If not, your CPU is fast enough.

At any rate, one thing you can do is, instead of running two doublechecks simultaneously, run 1 DC with two threads. That would reduce the time taken without (hopefully) too much loss in productivity.

[LaurV]

Originally Posted by TheMawn

It's too bad the user didn't figure out that if one starts at the final iteration and works backward, there isn't any need to go all the way to the very beginning.

[edit: joking apart, assuming one has a very fast "magic" method to extract a modular square root for a non-prime modulus, then it should worth starting from the end, for example you take the last iteration which you assume it gave x^2-2=0, and find x as sqrtmod(2,Mp) (this is trivial), then previous iteration y^2-2=x, and find y as sqrtmod(x+2, Mp), and so on. It can be proved that you can go all the way to the first iteration only if Mp is prime. Otherwise you are dead after the second step, i.e. sqrtmod(sqrtmod(2,Mp)+2,Mp) has no solution for a composite Mp, which would be a very fast compositeness test for mersenne numbers].

[edit 2: of course, if one would have such a "magic" method, we won't need any test at all, because factoring the Mp would be easier, one would use this method to find a non-trivial square root of 1 (or of 2) mod Mp and apply difference of squares, considering 1 is a square, or considering that a trivial root of 2 is 2^((p+1)/2). Ex, if we want to factor 2047, we apply the magic square root method to find that 622 is a square root of 1 mod 2047, because 622^2=1 (mod 2047), so (622-1)(622+1)=0 mod 2047, and we get the factors as gcd(621,2047)=23 and gcd (623,2047)=89. Or, we can find a nontrivial square root of 2, i.e. 915^2=2 (mod 2047), and we know a trivial root of 2, i.e. 2^((11+1)/2)=2^6=64, because 64^2=2 (mod 2047) so we get (915-64)(915+64)=0 (mod 2047) and taking the gcds we find the two factors]

[ATH]

Originally Posted by NBtarheel_33

We already have listed the date on which we finished double-checking everything under one million digits.

Where is that date? It is somewhere between these 2 but I do not see it:

May 20, 2001 All exponents less than 4,000,000 double-checked.
May 19, 2000 Double-checking proves M(2976221) and M(3021377) are the 36th and 37th Mersenne primes.

I can narrow it down using some old status files I have:
January 28th, 2001: All exponents below 3,210,800 have been tested and double-checked.
March 25th, 2001: All exponents below 3,502,500 have been tested and double-checked.

[ATH]

Checking the milestones list against some old status files:

April 15, 2002 All exponents below 9,000,000 tested at least once.
This seems a few days late:
March 31, 2002 All exponents below 8,574,000 have been tested at least once.
April 7, 2002 All exponents below 9,005,900 have been tested at least once.

7M double-check milestones is missing, it is approximately:
Februar 16, 2003 All exponents below 6,977,600 have been tested and double-checked.
Februar 27, 2003 All exponents below 7,060,000 have been tested and double-checked.




Since august 2009 until october 2014 I have archived the milestones list hourly.

Double-check milestones:
October 30, 2009 All exponents below 19,000,000 double-checked. (This milestone occurred October 28, 2009 at 12pm UTC)
21M double-check is missing: It occurred July 11, 2010 8am UTC)
23M and 24M double-check is missing: It occurred December 1, 2011 3am UTC (went from 22,545,883 to 24,052,939)
26M double-check is missing: It occured December 20, 2012 4am UTC

First time milestones:
28M: February 10, 2010 4pm UTC
29M: July 14, 2010 11pm UTC
30M: August 2, 2010 2pm UTC
31M: August 6, 2010 6pm UTC
32M-37M: December 25 2010 7am UTC (went from 31,494,937 to 37,591,483)
38M: July 19, 2011 1am UTC
39M: July 22, 2012 10am UTC
40M: August 2, 2012 3am UTC
41M: August 5, 2012 4pm UTC
42M+43M: September 5, 2012 12pm UTC (went from 41,959,639 to 43,142,591)
44M: November 9, 2012 12am UTC
45M: December 12, 2013 12am UTC



Milestones graph: milestones.png

[NBtarheel_33]

Originally Posted by ATH

Where is that date? It is somewhere between these 2 but I do not see it:

May 20, 2001 All exponents less than 4,000,000 double-checked.
May 19, 2000 Double-checking proves M(2976221) and M(3021377) are the 36th and 37th Mersenne primes.

I can narrow it down using some old status files I have:
January 28th, 2001: All exponents below 3,210,800 have been tested and double-checked.
March 25th, 2001: All exponents below 3,502,500 have been tested and double-checked.

You're right. It looks like we only recorded the completion of all first-time tests under a million digits:

December 26, 1998 All Mersenne numbers less than a million digits tested at least once.