On Mon, Nov 21, 2011 at 09:00, Thomas Witkowski < Thomas.Witkowski at tu-dresden.de> wrote:
> I have to multiple two matrices, one is implicitly defined by a KSP, the > other one is explicitly assembled. So when using KSPSolve(), it must be > called for each column of the second matrix? This seems not to be very > efficient as I thought the matrices are stored row wise? Is there a way to > get the columns of a SEQAIJ matrix? In this context, I think it is easier to store the matrix as a collection of column vectors, but you can also use MATDENSE. This thing isn't sparse (and it wouldn't do you any good anyway; there are few algorithms that can solve sparse right hand sides and there isn't much point because the solutions would still be dense). -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20111121/eea65bfa/attachment.htm>
