Dear all, I'd like to find the maximum eigenvalue from a mixed generalised eigenvalue problem. Has anyone tried this? I can follow the QG slepc example but I would need to assemble monolithic PETSc matrices. Is there a way to assemble monolithic PETSc matrices for mixed systems? cheers --cjc
On 14 Jan 2019, at 18:37, Cotter, Colin J <colin.cotter@imperial.ac.uk> wrote:
Dear all, I'd like to find the maximum eigenvalue from a mixed generalised eigenvalue problem. Has anyone tried this?
I can follow the QG slepc example but I would need to assemble monolithic PETSc matrices.
Is there a way to assemble monolithic PETSc matrices for mixed systems?
Yes. assemble(a, ..., mat_type="aij") Cheers, Lawrence
On Mon, Jan 14, 2019 at 2:38 PM Lawrence Mitchell <wence@gmx.li> wrote:
On 14 Jan 2019, at 18:37, Cotter, Colin J <colin.cotter@imperial.ac.uk> wrote:
Dear all, I'd like to find the maximum eigenvalue from a mixed generalised eigenvalue problem. Has anyone tried this?
I can follow the QG slepc example but I would need to assemble monolithic PETSc matrices.
Is there a way to assemble monolithic PETSc matrices for mixed systems?
Yes. assemble(a, ..., mat_type="aij")
The other option, if you have the action of the inverse of B, is to use a shell matrix for B^{-1} A. This is what I do when B is the smoother matrix. Thanks, Matt
Cheers,
Lawrence _______________________________________________ firedrake mailing list firedrake@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/firedrake
-- 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 https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
The other option, if you have the action of the inverse of B, is to use a shell matrix for B^{-1} A. This is what I do when B is the smoother matrix.
Yes, that's a good point, because then I have control over the solver options for the action of B^{-1}, thanks Matt. I'll look into how the petsc4py interface works with that. all the best --cjc
participants (3)
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Cotter, Colin J
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Lawrence Mitchell
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Matthew Knepley