#include "petsctao.h" PetscErrorCode TaoMatGetSubMat(Mat M, IS is, Vec v1, TaoSubsetType subset_type, Mat *Msub)
| M | - the full matrix (n x n) | |
| is | - the index set for the submatrix (both row and column index sets need to be the same) | |
| v1 | - work vector of dimension n, needed for TAO_SUBSET_MASK option | |
| subset_type | - the method TAO is using for subsetting (TAO_SUBSET_SUBVEC, TAO_SUBSET_MASK, TAO_SUBSET_MATRIXFREE) |