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2017-12-27, 07:02   #12
ewmayer
2ω=0

Sep 2002
República de California

2·13·443 Posts

Quote:
 Originally Posted by Prime95 A day after Christmas a computer has reported a new Mersenne prime. Unlike the numerous CudaLucas false positives we've had over the last few years, this one shows promise.
Quote:
 Originally Posted by Madpoo Otherwise, my verification won't technically count as a double-check since it's another Prime95 run and we'd still want one with another program (mprime, cudalucas, cllucas, etc).
When I read George's OP his wording led me to understand that the prime-reporting run was done using CuLu ... but Aaron, you say it was in fact a Prime95 (or mprime) run?

@Serge: I don't recall if Gord Palameta (a.k.a. GP2) did timings for 16-or-more-core C5 instances, and if so, how those compared to the EC2-instance timings you got for your verify run of the last prime 2 years ago. I'll try to dig up some numbers tomorrow.

Last fiddled with by ewmayer on 2017-12-27 at 07:04

 2017-12-27, 07:27 #13 a1call     "Rashid Naimi" Oct 2015 Remote to Here/There 23×3×79 Posts A positive PRP test result for the candidate you are testing, would be a relativity quick test with a very strong indication that you do not have a false-positive. Would it not?
2017-12-27, 07:48   #14
ewmayer
2ω=0

Sep 2002
República de California

2CFE16 Posts

Quote:
 Originally Posted by a1call A positive PRP test result for the candidate you are testing, would be a relativity quick test with a very strong indication that you do not have a false-positive. Would it not?
I don't see the advantage of using a PRP test in this context ... no faster than LL, and on the highly-reliable (typically with ECC RAM) systems usually used by George & Aaron for their 'first look' DCs the kinds of system glitches the Gerbicz error check is designed to catch are unlikely to come into play. Also, if the initial run used LL, using LL for the DC allows direct cross-comparison of intermediate Res64s, if the user's logfile is available. (At least I would hope it would work this way.)

Even if the original run didn't output interim residues in the manner I describe, when George/Aaron do their DC they set the flag to do so, which means if their run also says 'prime', then the official independent-software DCs can do such interim-residue cross-matching ... this is especially important for the GPU clients, which are very fast but error-prone, to be able to tell if the GPU DC has gone off the rails, in which case it is restarted from the most-recent interim savefile whose Res64 matches the Prime95 DC one.

Last fiddled with by ewmayer on 2017-12-27 at 07:52

2017-12-27, 10:00   #15
axn

Jun 2003

111258 Posts

Quote:
 Originally Posted by Madpoo What's the fastest GPU out there now for LL testing... Titan of some flavor?
Titan V. Probably will do this in under 18 hours. IIRC, TheJudger posted some benchies on it.

2017-12-27, 10:04   #16
Prime95
P90 years forever!

Aug 2002
Yeehaw, FL

11011111011112 Posts

Quote:
 Originally Posted by Uncwilly Did the e-mail system work?
Of course not. Chalk up yet another failure for this particular PHP code. I've asked Aaron and James to investigate.

What's weird is I copied that code for the recent PRP changes. I've successfully received several Mersenne-cofactor-is-PRP emails over the last few months.

Quote:
 Did the residue masking work? (And is there a clue somewhere?)
The quick look around I did on the web site showed nothing of interest. Perhaps someone here can find a web page that doesn't mask the result as well as it should.

Quote:
 Can we assume that this is a WR or should we assume that this is a Double Check? Also, I would assume, based upon the times your are talking about, this is not in the 100M digit range.
You may assume anything you like

Last fiddled with by Prime95 on 2017-12-27 at 10:10

2017-12-27, 10:05   #17
axn

Jun 2003

13×192 Posts

Quote:
 Originally Posted by TheJudger CUDA 9.0, CUDA driver 384.98, CUDALucas 2.05.1 (SVN rev. 99) Benchmark FFT sizes './CUDALucas -cufftbench 2048 32768 20' Code: Device Tesla V100-PCIE-16GB Compatibility 7.0 clockRate (MHz) 1380 memClockRate (MHz) 877 fft max exp ms/iter 4375 80897867 0.9595 4608 85111207 0.9649 5184 95507747 1.0124 Oliver
Assuming 82M expo, Titan V should complete it in under 24 hrs.
EDIT:- The above benchmark is for a Tesla V100 which ought to be faster than Titan V.

Last fiddled with by axn on 2017-12-27 at 10:07

 2017-12-27, 10:08 #18 Prime95 P90 years forever!     Aug 2002 Yeehaw, FL 157578 Posts @Ernst: Yes, the initial run was done with Prime95. Madpoo's unofficial DC is also with prime95. An mlucas run and a CudaLucas run would be a good idea. Volunteers?
2017-12-27, 10:24   #19
ET_
Banned

"Luigi"
Aug 2002
Team Italia

2·2,383 Posts

Quote:
 Originally Posted by Prime95 Prime95 version 28.9 was used. Thus, no Jacobi checking during the run or at the end of the run.
Then I'm not the one who found it

As you know, I am maintaining the DoubleMersenne site. It would be nice to know the exponent in advance (once confirmed) to start the sieving (it should be tested up to at least 600T, or 210 CPU/days) and set up the updated pages.

Last fiddled with by ET_ on 2017-12-27 at 10:34

2017-12-27, 10:29   #20
Prime95
P90 years forever!

Aug 2002
Yeehaw, FL

715110 Posts

Quote:
 Originally Posted by ET_ Then I'm not the one who found it
So sorry, maybe next time.

I reached the potential discoverer by email. Of course, he/she is traveling and cannot send the last intermediate file to me. We have to wait for madpoo.

2017-12-27, 11:11   #21
ATH
Einyen

Dec 2003
Denmark

1011011101012 Posts

Quote:
 Originally Posted by Prime95 @Ernst: Yes, the initial run was done with Prime95. Madpoo's unofficial DC is also with prime95. An mlucas run and a CudaLucas run would be a good idea. Volunteers?
I would like to start a Titan Black run and I could start a mlucas run on a C5 instance, I just need to compile mlucas on it.

The fastest GPU right now is the Tesla P100 and TheJudger might have one, as he has posted benchmarks.

Last fiddled with by ATH on 2017-12-27 at 11:11

 2017-12-27, 12:11 #22 TheJudger     "Oliver" Mar 2005 Germany 100010100112 Posts Fastest GPU today should be Tesla V100 - TITAN V has "crippled" memory bandwidth and thus should be slower because CUDAlucas is memory bandwidth bound on this type of hardware. Oliver Last fiddled with by TheJudger on 2017-12-27 at 12:12

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