MatSchurComplementComputeExplicitOperator#

Compute the Schur complement matrix explicitly

Synopsis#

#include "petscksp.h" 
PetscErrorCode MatSchurComplementComputeExplicitOperator(Mat A, Mat *S)

Collective

Input Parameter#

A - the matrix obtained with MatCreateSchurComplement()

Output Parameter#

S - the Schur complement matrix

Notes#

This can be expensive when S is large, so it is mainly for testing

Use MatSchurComplementGetPmat() to get a sparse approximation for the Schur complement suitable for use in building a preconditioner

S will automatically have the same prefix as A appended by explicit_operator_, there are three options available: -fieldsplit_1_explicit_operator_mat_type, -fieldsplit_1_explicit_operator_mat_symmetric, and -fieldsplit_1_explicit_operator_mat_hermitian

Developer Note#

The three aforementioned should not be parsed and used in this routine, but rather in MatSetFromOptions()

Level#

advanced

Location#

src/ksp/ksp/utils/schurm/schurm.c

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Index of all manual pages