20190503, 19:51  #56 
∂^{2}ω=0
Sep 2002
República de California
11,743 Posts 
Has anyone heard from David Stanfill, a.k.a. airsquirrels, of late? I had my 2 sidebyside tests of F30 running on a pair of servers he hosts, one the GIMPS KNL (doing the run @64M FFT, last check ~70% done) another a 32core Intel Xeon server (doing the run @60M FFT). The Xeon started its run some months after the KNL but was running faster (~55 ms/iter versus 68 ms/iter) and had pulled ahead of the KNL early this year. But I lost ability to ssh into it (from the KNL is only option, the way David configured things) a couple months ago, sent David several emails to that effect, no reply. And as of several days ago I can no longer access the KNL, either. I'm starting to get a bit worried  his forum profile indicates last activity back in January.

20190503, 20:04  #57  
Sep 2002
Database er0rr
2·2,141 Posts 
Quote:
http://press.airsquirrels.com/2019/0...researchlabs/ I guess he is really busy! Last fiddled with by paulunderwood on 20190503 at 20:06 

20190503, 20:09  #58  
∂^{2}ω=0
Sep 2002
República de California
11,743 Posts 
Quote:


20190503, 20:17  #59  
Sep 2002
Database er0rr
2×2,141 Posts 
Quote:
http://www.squirrelsresearch.com/contact/ HTH Last fiddled with by paulunderwood on 20190503 at 20:18 

20190503, 20:55  #60  
∂^{2}ω=0
Sep 2002
República de California
10110111011111_{2} Posts 
Quote:


20190503, 23:21  #61 
May 2019
2 Posts 
NO MORE FERMAT PRIMES
Here’s the proof that there are no more Fermat Primes:
The following website calculates the total number of integers that equal a given totient number: http://www.numbertheory.org/php/carmichael.html Plug in n = 2k, k ≥ 33 Plug in e = 0 Plug in f = 0 All the solutions for n = 2k (k ≥ 33), contain exactly 32 solutions. All 32 solutions are even and are equal to 2 * the solutions for the previous n. Because there are no odd numbers, and that all subsequent solutions will just be a power of 2 times any of the 32 previous solutions, then there can’t be any more prime numbers. Prime numbers are odd, and there’s only even solutions for n = 2k (k ≥ 33). Thererfore, there are no more fermat prime numbers. 
20190504, 05:10  #62 
Romulan Interpreter
"name field"
Jun 2011
Thailand
2·31·163 Posts 
Disclaimer: "2k" in your post should be read as 2^{k}.
Do you understand what that calculator does, and how? 
20190505, 21:54  #63 
∂^{2}ω=0
Sep 2002
República de California
11,743 Posts 
Still nary a peep from David ... I think I need to start looking for a new Xeon server to finish my F30 runs on ... what is the cheapest 32core avx2capable Xeon server in the severalyearsold usedhardware market, I wonder. The other problem is that while I have recent localdownload copies of the runstatus file and every10Miter savefiles for the 64MFFT run, my 60MFFT runstatus file is 56 months out of date, i.e. I have no proof that I did the last ~150M iters or so at that FFT length. Of course one can use the 10Miter savefiles to do a spedup parallel verification (multiple machines, each reproducing a separate 10Miter sbinterval), but rather a spot of bother in any event.

20190507, 00:45  #64 
Sep 2003
101000011011_{2} Posts 
Before Robert Gerbicz came up with Gerbicz error checking for PRP tests for Mersenne numbers, I think he invented something similar for Pépin tests.
So I wonder if it would make sense to pause the tests on F30 in order to incorporate error checking, to increase the confidence in the final result. 
20190509, 03:25  #65  
∂^{2}ω=0
Sep 2002
República de California
11,743 Posts 
Quote:
I've had a generous offer from a fellow forumite to use a 32core Skylake Xeon system he owns (or has access to) to finish F30  depending on what his detailed tuningrun timings looks like, we may be able to use 16 cores for each of 2 runs at 60M and 64M, respectively, and get throughput not much less than I was getting before. The only issue is the missing runstatus file documentation of the 60M run, where the last copy I ftp'ed over to my PC is iter ~530M, roughly 200Miter behind the last check of that run before the Avx2 Xeon went AWOL. I may simply start both 60M and 64M runs from the 740Miter savefile produced by the 64M run (last I copied to my PC before the KNL went AWOL), and hope to reach someone at Squirrels Inc who can help me recover the missing files between now and end of the year. Failing that I can redo the missing 200Miter starting with the 530Miter savefile at a later date in order to fill in the gap. Last fiddled with by ewmayer on 20190509 at 03:28 

20190509, 15:01  #66 
Aug 2002
3×2,837 Posts 
For future runs, started from scratch, would Gerbicz error checking eliminate the need for parallel runs?

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