On Thu, Oct 17, 2013 at 10:02 AM, James A Charles <[email protected]>wrote:
> Hello, > > I'm trying to use a Dense Parallel matrix where there are no nonzeros that > is rectangular of size Nxp where N >> p. P is anywhere from 2-6 typically > and N can be of size 1E6 or more. > > For this I would like to only distribute the rows along the MPI processes > and not have the columns distributed at all (local columns size = global > column size). What is the best way to do this in Petsc? If it matters I am > using Petsc3.4. > We do not distribute columns. You could if you used the Elemental implementation, but you do not need that. > The operations performed after the Matrix allocation are: > > direct call to Lapack for QR factorization via pointer to array. > You really want Tall-Skinny QR here (TSQR). We have not implemented it, but it is not hard, so if you would like to contribute it, that would be great. > Matrix multiply with an NxN matrix. > This works. Matt > I have this working in serial but when I try to distribute my matrices I > get columns with size p*(number of processes). > > Thanks, > James > > > > > > > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener
