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 2011-06-14, 23:09 #23 kar_bon     Mar 2006 Germany 24·3·61 Posts I've included a new page: First odd k, for which k*2^n-1 is prime, n<=10000 Maximum k-value so far: k=55999 for n=8867. A graph presents all values. I plan to continue this table and add such page for k*2^n+1, too.
2011-06-15, 17:10   #24
henryzz
Just call me Henry

"David"
Sep 2007
Cambridge (GMT/BST)

173416 Posts

Quote:
 Originally Posted by kar_bon I've included a new page: First odd k, for which k*2^n-1 is prime, n<=10000 Maximum k-value so far: k=55999 for n=8867. A graph presents all values. I plan to continue this table and add such page for k*2^n+1, too.
Are you using ppsieve for this? I suspect for sieving a large range of starting k from 1 it would be faster.

2011-06-16, 07:40   #25
kar_bon

Mar 2006
Germany

24·3·61 Posts

Quote:
 Originally Posted by henryzz Are you using ppsieve for this? I suspect for sieving a large range of starting k from 1 it would be faster.
No. I used pfgw for this range of small primes.
Most of the values are already known in my database (where k<10000), so only the k-values >10000 were done new.

 2011-07-08, 09:49 #26 kar_bon     Mar 2006 Germany 24·3·61 Posts Status 2nd Quarter 2011 Riesel: 8062 k-values (7+) 164378 primes (1436+) 3462 twins (5+) 10565 Top5000-links (1033+) Proth: 5000 k-values 149539 primes 2271 twins 21819 Top5000-links - Changes since last Status (3rd Quarter 2010) - Proth-side still only k-values < 10000 - Stats-page, Prime- and Twin-lists (for download) will be updated later today
 2011-07-09, 01:24 #27 kar_bon     Mar 2006 Germany 24×3×61 Posts I've included a 'new' page with my first version of these pages online in 2007 at RPS to see, how much the data and lookalike changed since then. There's also a link to the thread in this forum, where I announced that page and the development is shown. You can find these updates in the Menu 'General' -> 'History'.
 2011-07-15, 22:02 #28 kar_bon     Mar 2006 Germany 24·3·61 Posts I've included a new page for the first odd k, for which k*2^n+1 is prime, n<=10000. A graph is shown, too.
 2011-07-17, 03:46 #29 Christenson     Dec 2010 Monticello 179510 Posts I need to ask if you are interested in having CUDA TF available...
2011-07-17, 11:13   #30
kar_bon

Mar 2006
Germany

55608 Posts

Quote:
 Originally Posted by Christenson I need to ask if you are interested in having CUDA TF available...
About 95% of my time I'm participating in the NPLB project and the ranges are already sieved to best fit.

The last page I've done with PFGW, so no need to sieve fast and deep.

 2011-07-17, 12:51 #31 Christenson     Dec 2010 Monticello 179510 Posts At least with Mersennes, TF on CUDA can be ~100x faster than TF on CPUs...moving up the optimum sieving by half a dozen bits.
2011-07-17, 16:13   #32
davieddy

"Lucan"
Dec 2006
England

2·3·13·83 Posts

Quote:
 Originally Posted by Christenson At least with Mersennes, TF on CUDA can be ~100x faster than TF on CPUs...moving up the optimum sieving by half a dozen bits.
Not quite sure what you mean by "optimum", but I do understand
"hitting the wall". That is the nature of exponential growth.
2^7 =128

 2011-07-17, 16:24 #33 Christenson     Dec 2010 Monticello 34038 Posts By optimum I mean minimizing the total expected effort expended against a given set of interesting expressions/numbers to classify them all. For mersenne numbers, that means showing that a factor exists and once in a long while showing that it doesn't. For these, it might be getting to a known factor or knowing the expression is prime.

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