#include "petscksp.h" PetscErrorCode MatSchurComplementGetPmat(Mat S,MatReuse preuse,Mat *Sp)Collective on S
|S||- matrix obtained with MatCreateSchurComplement() (or equivalent) that implements the action of A11 - A10 ksp(A00,Ap00) A01|
|preuse||- MAT_INITIAL_MATRIX for a new Sp, or MAT_REUSE_MATRIX to reuse an existing Sp, or MAT_IGNORE_MATRIX to put nothing in Sp|
|Sp||- approximate Schur complement suitable for preconditioning the exact Schur complement S = A11 - A10 inv(A00) A01|
Sometimes users would like to provide problem-specific data in the Schur complement, usually only for special row and column index sets. In that case, the user should call PetscObjectComposeFunction() to set "MatSchurComplementGetPmat_C" to their function. If their function needs to fall back to the default implementation, it should call MatSchurComplementGetPmat_Basic().
This routine should be called MatSchurComplementCreatePmat()