[petsc-users] MatCreateSchurComplementPmat to create a Schur complement

[Tang, Qi]

Thanks, Matt. That works now.
________________________________
From: Matthew Knepley <knepley at gmail.com>
Sent: Thursday, January 21, 2021 9:29 AM
To: Tang, Qi <tangqi at msu.edu>
Cc: PETSc users list <petsc-users at mcs.anl.gov>
Subject: Re: [petsc-users] MatCreateSchurComplementPmat to create a Schur complement

On Thu, Jan 21, 2021 at 2:52 AM Tang, Qi <tangqi at msu.edu<mailto:tangqi at msu.edu>> wrote:
Hi,
When I use the MatCreateSchurComplementPmat to create a Schur complement for my own usage, I do not understand the logic when preuse=MAT_INITIAL_MATRIX. If all the matrixes are not empty, the first thing it did is
809:     MatDestroy(Spmat);
So that means I cannot pass in an empty matrix. It works if I first do MatCreate a dummy matrix and then pass in. Is that just some inconsistency or is there something I misunderstood?

Yes, it wants you to pass &Sp with Sp == NULL. Sorry this is not more clear.

  Thanks,

     Matt

Qi


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