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-   Riesel Prime Data Collecting (k*2^n-1) (https://www.mersenneforum.org/forumdisplay.php?f=89)

 kar_bon 2011-06-14 23:09

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.

 henryzz 2011-06-15 17:10

[QUOTE=kar_bon;263806]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.[/QUOTE]
Are you using ppsieve for this? I suspect for sieving a large range of starting k from 1 it would be faster.

 kar_bon 2011-06-16 07:40

[QUOTE=henryzz;263856]Are you using ppsieve for this? I suspect for sieving a large range of starting k from 1 it would be faster.[/QUOTE]

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.

 kar_bon 2011-07-08 09:49

Status 2nd Quarter 2011

[b]Riesel:[/b]
8062 k-values (7+)
164378 primes (1436+)
3462 twins (5+)

[b]Proth:[/b]
5000 k-values
149539 primes
2271 twins

- 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

 kar_bon 2011-07-09 01:24

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.

 kar_bon 2011-07-15 22:02

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.

 Christenson 2011-07-17 03:46

I need to ask if you are interested in having CUDA TF available...

 kar_bon 2011-07-17 11:13

[QUOTE=Christenson;266655]I need to ask if you are interested in having CUDA TF available...[/QUOTE]

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.

 Christenson 2011-07-17 12:51

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.

 davieddy 2011-07-17 16:13

[QUOTE=Christenson;266679]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.[/QUOTE]

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

 Christenson 2011-07-17 16:24

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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