On 10/4/07, Simon King <[EMAIL PROTECTED]> wrote: > > Dear sage-support team, > > i'm trying to convince my boss about using modern linear algebra > software (as part of a project on group cohomology rings). However, i > need better arguments. Perhaps you have some?
This is separate from your question, but in SAGE some wrappers for Graham Ellis' HAP package have been written. http://www.sagemath.org/doc/html/ref/module-sage.groups.perm-gps.permgroup.html#l2h-3081 Also, the plan is to have HAP included with SAGE "soon". This extra functionality might be another reason why SAGE and linbox is a good idea. > > I wrote a toy dynamic module for Sage providing two test functions: > 1. - Read a square matrix over a finite field from a MeatAxe file > - convert it into a Sage matrix > - multiply it n times with itself > - return the result > 2. - Read a square matrix over a finite field from a MeatAxe file > - multiply it n times with itself by using MeatAxe > - convert the result into a Sage matrix > - return it > > I was not interested in the result (computing M^1000001 in sage needs > almost no time), but i was interested in the time of a single matrix > multiplication. Therefore i've put the multiplications into a loop, > compiled using sage -cython. > > When i take a 4x4 matrix over GF(7) with n=1000001, test function 1 > needs 92.50 s CPU time, but test function 2 only needs 1.49 s CPU > time! > Hence, in that case, MeatAxe (actually a very old version!!) appears > to be faster than Sage built with Atlas, by a factor of >60! > On the other hand, a single multiplication of very large (4000x4000) > random matrices over GF(2) in Sage is faster than multiplication in > MeatAxe, by a factor of about 5. > > Do you have an explanation of that phenomenon? I do think the two test > functions are fair, as in both cases we have exactly one matrix > conversion and the loop -- the only difference is whether one uses > multiplication by Sage or by MeatAxe. > > Yours sincerely > Simon > > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---
