On Friday, 19 October 2012 20:35:07 UTC+8, jason wrote: > > On 10/19/12 7:25 AM, Dima Pasechnik wrote: > > While some ARPACK functionality is available in Sage from scipy (more is > > implemented in scipy 0.11, than in currently available in Sage scipy > > 0.9, but this is taken care of in #13541, which I'm reviewing > presently), > > the functionality allowing to implement matrices as callback functions > > (sometimes a big win in memory/speed) seems to be missing. > > > > Any idea how can this be handled? > > > > Do you mean a sparse matrix class where A[i,j] actually calls some > function that you supply?
right. > I'd make a subclass of sparse matrices (or > maybe even dense matrices??), and just override the unsafe indexing > method. I think all indexing ends up going through that function. well, it does not look that obvious (it's sparse scipy/numpy matrices: http://docs.scipy.org/doc/scipy/reference/sparse.html) and they have several member functions, such as __getitem__, _get_row_slice, etc... Hmm, I actually thought they are way more optimized, than what I saw in sage/scipy/sparse/csr.py Thanks a lot anyway, Dima > > > Thanks, > > Jason > > > > > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To post to this group, send email to sage-devel@googlegroups.com. To unsubscribe from this group, send email to sage-devel+unsubscr...@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel?hl=en.
