On Mon, Feb 13, 2012 at 11:07 AM, Jason Grout <jason-s...@creativetrax.com> wrote: > On 2/13/12 12:41 PM, William Stein wrote: >> >> On Mon, Feb 13, 2012 at 10:29 AM, Robert Bradshaw >> <rober...@math.washington.edu> wrote: >>> >>> On Mon, Feb 13, 2012 at 10:06 AM, William Stein<wst...@gmail.com> wrote: >>>> >>>> On Mon, Feb 13, 2012 at 9:59 AM, Pierre<pierre.guil...@gmail.com> >>>> wrote: >>>>> >>>>> I see. Well I *do* have hundreds of 2x2 matrices to multiply out so >>>>> i'm better off storing them as numpy matrices throughout... thanks for >>>>> your explanations though. >>>>> >>>>> Pierre >>>> >>>> >>>> You might consider using Cython and writing a custom 2x2 matrix class. >>>> It wouldn't be difficult... so I'll write one right now and respond >>>> with the benchmarks. >> >> >> Here it is: http://480.sagenb.org/home/pub/97/ >> >> I ended up using GSL's complex matrix data type and the BLAS level 3 >> routine to do the multiplication. I did not add any other >> convenience functions to the class, so some more will probably be >> needed for your application. > > > I'm curious why you didn't just store the 4 complex numbers in C.
I was concerned about "numerical stability" and figured BLAS would deal with that. But maybe that doesn't matter. Most importantly, I forgot about Cython's complex type, which I now remember Robert Bradshaw wrote for his thesis work. I wasn't looking forward to writing your line: res.m00=self.m00*right.m00+self.m01*right.m10 but against the gsl library. But using the cython type in complex, you get the above at C speed with easy notation, which is pretty awesome. > I tried > it and got a much bigger speedup: 17x faster than numpy and 150x faster than > Sage. See http://sagenb.org/home/pub/4303/ Nice. > > Thanks, > > Jason > > > -- > To post to this group, send email to sage-support@googlegroups.com > To unsubscribe from this group, send email to > sage-support+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/sage-support > URL: http://www.sagemath.org -- William Stein Professor of Mathematics University of Washington http://wstein.org -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
