On Wednesday, 21 September 2011 15:21:00 UTC+8, Nicolas M. Thiéry wrote: > > On Tue, Sep 20, 2011 at 08:11:39AM -0700, Dima Pasechnik wrote: > > In my case, sometimes keeping multiplication coefficients, even in a > > sparse form, is less efficient than recomputing them over and over > again, > > from a set of sparse matrix generators. > > I am confused. When you say "set of sparse matrix generators" do you > mean "algebra generators" or "basis of the algebra"? >
I mean the basis of the algebra; specifically, orbitals (a.k.a. 2-orbits) of a permutation group, considered as 0-1 matrices. Say, consider the problem of finding the eigenvalues of a particular element of the algebra, given as a linear combination of the basis elements. When the dimension of the algebra is small compared to the size of the domain on which the permutation group acts, even the regular representation of the algebra is must faster to deal with than the original basis matrices. When this is the other way around, it's better to deal with the original basis matrices directly. Dima > Cheers, > Nicolas > -- > Nicolas M. Thi�ry "Isil" <nth...@users.sf.net> > http://Nicolas.Thiery.name/ > > -- 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
