PETSc version 3.17.4
Fix/Edit manual page

# MatCreateNest

Creates a new matrix containing several nested submatrices, each stored separately

### Synopsis

    #include "petscmat.h"
    PetscErrorCode MatCreateNest(MPI_Comm comm,PetscInt nr,const IS is_row[],PetscInt nc,const IS is_col[],const Mat a[],Mat *B)

Collective on Mat

### Input Parameters

| comm | - Communicator for the new Mat
| nr | - number of nested row blocks
| is_row | - index sets for each nested row block, or NULL to make contiguous
| nc | - number of nested column blocks
| is_col | - index sets for each nested column block, or NULL to make contiguous
| a | - row-aligned array of nr*nc submatrices, empty submatrices can be passed using NULL

### Output Parameter

| B | - new matrix

### See Also

MatCreate(), VecCreateNest(), DMCreateMatrix(), MATNEST, MatNestSetSubMat(),
MatNestGetSubMat(), MatNestGetLocalISs(), MatNestGetSize(), MatNestGetISs(), MatNestSetSubMats(), MatNestGetSubMats()

### Level

advanced

### Location

src/mat/impls/nest/matnest.c

### Examples

src/ksp/ksp/tutorials/ex81.c.html
src/snes/tutorials/ex70.c.html
src/snes/tutorials/ex73f90t.F90.html
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages