#include "petscksp.h" PetscErrorCode MatSchurComplementSetSubMatrices(Mat S,Mat A00,Mat Ap00,Mat A01,Mat A10,Mat A11)Collective on Mat
| S | - matrix obtained with MatCreateSchurComplement (or equivalent) and implementing the action of A11 - A10 ksp(A00,Ap00) A01 | |
| A00,A01,A10,A11 | - the four parts of A = [A00 A01; A10 A11] (A11 is optional) | |
| Ap00 | - preconditioning matrix for use in ksp(A00,Ap00) to approximate the action of A^{-1}. |
Notes: The Schur complement is NOT actually formed! Rather, this object performs the matrix-vector product by using formula S = A11 - A10 A^{-1} A01 for Schur complement S and a KSP solver to approximate the action of A^{-1}.
All four matrices must have the same MPI communicator.
A00 and A11 must be square matrices.