On Mon, Oct 5, 2015 at 2:29 PM, Jori Mäntysalo <jori.mantys...@uta.fi> wrote:
> Just a stupid side-question: > > On Sun, 4 Oct 2015, Victor Shoup wrote: > > Also, now that NTL is threadsafe, I'm looking at making some of the >> low-level routines thread enhanced. >> > > For up to 4 threads, I get close to linear speedup...but after that, it >> starts to degrade: at 16 threads I only get 8x speedup. >> > > Isn't this what always happen with parallel computing? Computing in 1 > thread takes for example 100 seconds. With 2 cores it takes 100/2+1=51, > assuming that overhead for thread handling is 1 second. And at some point > overhead will be too much, or memory IO will be bottleneck. > > Now let's suppose that Sage has users A and B. A wants to compute one hard > thing - say, factor one big integer. B wants to compute many things - say, > factor 100 medium-size integers. For B it would be best to have no > threading at all on lower level, just very simple upper level wrapper. > > I have been asked to answer mostly type B questions, but sometimes also of > type A. > > * * * > > If I am right, there is no EASY parallel functions in Sage. Let G be a > list of 1000 immutable graphs. How to run > > C = [g.chromatic_number() for g in G] > > in parallel? AFAIK we have no "parallel_apply()" or similar. > Check out http://doc.sagemath.org/html/en/reference/parallel/index.html David > > -- > Jori Mäntysalo > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
