20190517, 06:27  #67  
Jun 2003
Oxford, UK
3·5^{4} Posts 
Quote:
My best overnight was 3938 280639717928435 25.379742 Merit formula: if the twin prime constant is pi(2), g= your reported gap, and n = your big 9e14 value, then the merit is 6g*pi(2)/ln(6n+1)^2 For TPC see https://primes.utm.edu/glossary/page...nPrimeConstant Last fiddled with by robert44444uk on 20190517 at 06:32 

20190517, 07:28  #68 
Just call me Henry
"David"
Sep 2007
Cambridge (GMT/BST)
2·2,861 Posts 
How does newpgen compare with fbncsieve for speed? I think that is probably worth investigating

20190517, 08:00  #69  
Jun 2003
Oxford, UK
3×5^{4} Posts 
Quote:
I think the best solution without doubt would come if someone could update Robert Gerbicz's cprogram that was used to generate prime gaps  1e15 took no time at all! 

20190517, 08:02  #70  
Jun 2003
Oxford, UK
1875_{10} Posts 
Quote:
3016 280841015355407 Last fiddled with by robert44444uk on 20190517 at 08:03 

20190517, 10:28  #71  
Jun 2003
Oxford, UK
3·5^{4} Posts 
Quote:
Code:
#!/usr/bin/env perl use warnings; use strict; use Math::GMPz; use Math::BigFloat lib=>"GMP"; use Math::Prime::Util qw/:all/; use v5.10; use List::MoreUtils qw/all/; use Timer::Runtime; $=1; my $interval = 200_000_000; my $overlap = 10_000; my $numberofiterations = 10; my $from = 3.7e14; my $reportsmallgapmult = 1_800; for (my $k=0; $k <= $numberofiterations; $k++) { my $fromnew = $from+$k*$interval; my $endnew = $fromnew+$interval+$overlap; say "doing from ", $fromnew, " to ",$endnew; my $start = 6*$fromnew; my $end = $start+($interval+$overlap)*6; my @twins = sieve_prime_cluster($start, $end, 2); for (my $l=1; $l <= scalar @twins1; $l++) { my $gap = ($twins[$l]$twins[$l1]); if ($gap>=$reportsmallgapmult*6) { my $firsttwin = ($twins[$l1]+1)/6; my $reportedgap = $gap/6; say $reportedgap, " ", $firsttwin; } } } 

20190517, 21:17  #72 
Apr 2010
Over the rainbow
3×11×73 Posts 
another showing off
Code:
3104 9001387635261233 
20190520, 09:45  #73 
Feb 2003
3·5·127 Posts 

20190520, 12:35  #74  
Feb 2003
1905_{10} Posts 
Quote:
On my machine it takes only about 30 seconds. And in comparison with the newpgen/perl combo it is actually much faster! (3 secs vs. 10.3 secs per 2e8 block). 

20190520, 13:47  #75 
Feb 2003
3·5·127 Posts 
My timings above are for Linux.
I did the same test (for only one iteration) on the same machine under Windows 10 and there it is much slower: 2 minutes (Win) vs. 3 secs (Linux)! Could be some (optimization) issue with the Perl modules (I'm using Strawberry Perl on Windows). Last fiddled with by Thomas11 on 20190520 at 13:48 
20190520, 16:27  #76 
Apr 2010
Over the rainbow
3·11·73 Posts 

20190520, 18:50  #77  
Jun 2003
Oxford, UK
3·5^{4} Posts 
Quote:
Can anyone make the perl program multithread? Last fiddled with by robert44444uk on 20190520 at 18:55 

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