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. 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
