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
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