#include "petscmat.h" PetscErrorCode MatNestGetSubMat(Mat A,PetscInt idxm,PetscInt jdxm,Mat *sub)Not collective
| A | - nest matrix | |
| idxm | - index of the matrix within the nest matrix | |
| jdxm | - index of the matrix within the nest matrix |
| sub | - matrix at index idxm,jdxm within the nest matrix |