I suspect this is precisely the case. Please do open an issue. On Wed, Jan 7, 2015 at 12:24 PM, Kevin Squire <[email protected]> wrote:
> I would suggest doing a quick search on github for any issues related to > sparse matrices, and if none are relevant, opening a new one. One likely > possibility is that neither function has been specialized for sparse > matrices, and that the general fallback version of these functions are slow > for sparse matrices. In either case, a specialized function should be easy > to code. > > Cheers, > Kevin > > On Wed, Jan 7, 2015 at 9:20 AM, Christoph Ortner < > [email protected]> wrote: > >> I don't have a solution, but a related comment: slicing of large sparse >> matrices is very slow too. E.g., I like to assemble a stiffness matrix (for >> a PDE) with free boundary conditions and then impose clamped boundaries by >> taking a subset of the matrix, >> B = A[Ifree, Ifree] >> this is so slow that I had to completely give up on it and rewrite all my >> assembly codes. >> >> I suspect that the flipxx functions and this are a similar issue? >> >> Is there already an issue filed for this? >> >> Christoph >> >> >
