On Tue, Mar 27, 2012 at 2:39 PM, Volker Braun <vbraun.n...@gmail.com> wrote: > The current state is that we build static atlas with and without threads, > and the shared library without threads only. And our module_list.py links > with the single-threaded atlas shared library only. So Sage will use the > single-threaded version if you build atlas yourself. > > If you use the os-provided atlas library (which can be multi-threaded yet > not have the "pt" in the name), you get parallel atlas. For example, on > Fedora I'm using the system atlas and get > > sage: sage: a = random_matrix(RDF,1000) > sage: time a*a > 1000 x 1000 dense matrix over Real Double Field > Time: CPU 1.08 s, Wall: 0.26 s > > And if anybody wonders why there is a single-threaded atlas at all: People > often specifically WANT a single-threaded blas, and implement their own > parallelism on top of that.
I WANT a multithreaded atlas in Sage :-) -- William > > > > > On Tuesday, March 27, 2012 2:14:26 PM UTC+1, William wrote: >> >> On Tue, Mar 27, 2012 at 12:39 PM, Volker Braun <vbraun.n...@gmail.com> >> wrote: >> > When I rewrote the atlas spkg I enabled multithreaded atlas libraries. >> > That >> > is, we configure atlas to allow threading. Whether or not atlas actually >> > builds threaded libraries depends on os and configure checks for >> > ptthreads. >> >> Does it work on mod.math.washington.edu? I tried >> >> sage: a = random_matrix(RDF,1000) >> sage: time b = a*a >> Time: CPU 0.43 s, Wall: 0.43 s >> >> and clearly ATLAS is *NOT* being multithreaded. >> However, if I do the same on my little OS X laptop, I get: >> >> sage: a = random_matrix(RDF,1000) >> sage: time b = a*a >> Time: CPU 0.45 s, Wall: 0.13 s # <--- look at that walltime! >> >> which is clearly multithreaded. >> >> - William >> >> > >> > -- >> > To post to this group, send an email to sage-devel@googlegroups.com >> > To unsubscribe from this group, send an email to >> > sage-devel+unsubscr...@googlegroups.com >> > For more options, visit this group at >> > http://groups.google.com/group/sage-devel >> > URL: http://www.sagemath.org >> >> -- >> William Stein >> Professor of Mathematics >> University of Washington >> http://wstein.org > > -- > To post to this group, send an email to sage-devel@googlegroups.com > To unsubscribe from this group, send an email to > sage-devel+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/sage-devel > URL: http://www.sagemath.org -- William Stein Professor of Mathematics University of Washington http://wstein.org -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
