:orphan:
# MatNestSetSubMats
Sets the nested submatrices in a `MATNEST` 
## Synopsis
```
#include "petscmat.h"   
PetscErrorCode MatNestSetSubMats(Mat A, PetscInt nr, const IS is_row[], PetscInt nc, const IS is_col[], const Mat a[])
```
Collective


## Input Parameters

- ***A -*** `MATNEST` matrix
- ***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`





## Note
This always resets any submatrix information previously set


## See Also
 [](ch_matrices), `Mat`, `MATNEST`, `MatCreateNest()`, `MatNestSetSubMat()`, `MatNestGetSubMat()`, `MatNestGetSubMats()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/nest/matnest.c.html#MatNestSetSubMats">src/mat/impls/nest/matnest.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/nest/matnest.c.html#MatNestSetSubMats_Nest">MatNestSetSubMats_Nest in src/mat/impls/nest/matnest.c</A><BR>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/mat/impls/nest/matnest.c)


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