Re: How to efficiently count Proth primes with GP parfor?

[hermann@stamm-wilbrandt.de]

On 2024-03-20 23:59, Bill Allombert wrote:
> On Wed, Mar 20, 2024 at 11:20:50PM +0100, hermann@stamm-wilbrandt.de 
> wrote:
> > >
> > While using Karim's isProth2() I improved Bill's parallel work 
> > distribution
> > scheme.
> >
> > Instead of blocks of size B=n\nbt now block are of size 
> > B=n\nbt\if(l,l,1).
> > Since distribution of primes as well as distribution of Proth primes 
> > is not
> > the same for lower half ad higher half, making each of the 32 hardware
> > threaas work l smaller but more evenly distributed work areas.
>
> Something else you can try is to increase nbt, to have smaller blocks.
>
> Cheers,
> Bill.
Hi,

the environment variable "l" does exactly that, create smaller blocks:
https://gist.github.com/Hermann-SW/558728c025a1f2d3dace008292bac897#file-proth-gp-L13-L14

...
doit(n,l)={
  my(c=0,B=n\nbt\if(l,l,1));
...

See 1st gist comment for effects for your (l=1 (or undefined)) and 
L=2/4/8:
https://gist.github.com/Hermann-SW/558728c025a1f2d3dace008292bac897?permalink_comment_id=4995469#gistcomment-4995469

Regards,

Hermann.