On Wed, Aug 12, 2015 at 2:01 PM, Anthony Haas <a...@email.arizona.edu> wrote:
> Hi Hong, > > I have attached a schematic of my matrices. I solve a generalized EVP in > shift-and-invert mode. As you will see, I have indeed a zero diagonal block > in the matrices A and B (blocks 4,4). I guess I could just add the zero > entries to the diagonal elements of A? Is that strictly necessary when > using a direct (LU) solver? Can you please give me a short explanation of > why empty diagonal blocks can be problematic? > Yes, the sparse numbering schemes use the location of the diagonal for faster indexing in many places. Matt > Is the patch still available at: > https://bitbucket.org/petsc/petsc/commits/ceeba3afeff0c18262ed13ef92e2508ca68b0ecf > ? > > Thanks again, > > Anthony > > > > > > > On 08/12/2015 08:58 AM, Hong wrote: > >> Anthony, >> I just patched petsc-maint branch. >> >> Your matrix Amat_binary.m has empty diagonal blocks. Most petsc solvers >> require matrix diagonal entries to be allocated as 'non-zero', i.e., insert >> zero values to these zero entries. I would suggest you add zeros to >> Amat_binary.m during its buildup. This would enable petsc solvers, as well >> as other packages. >> >> Again, thanks for bug reporting. >> >> Hong >> >> > -- 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
