:orphan:
# MatNestGetISs
Returns the index sets partitioning the row and column spaces of a `MATNEST`
## Synopsis
```
#include "petscmat.h"
PetscErrorCode MatNestGetISs(Mat A, IS rows[], IS cols[])
```
Not Collective
## Input Parameter
- ***A -*** `MATNEST` matrix
## Output Parameters
- ***rows -*** array of row index sets
- ***cols -*** array of column index sets
## Note
The user must have allocated arrays of the correct size. The reference count is not increased on the returned `IS`s.
## See Also
[](ch_matrices), `Mat`, `MATNEST`, `MatNestGetSubMat()`, `MatNestGetSubMats()`, `MatNestGetSize()`, `MatNestGetLocalISs()`, `MATNEST`,
`MatCreateNest()`, `MatNestGetSubMats()`, `MatNestSetSubMats()`
## Level
advanced
## Location
src/mat/impls/nest/matnest.c
## Examples
src/ksp/ksp/tutorials/ex81.c
src/snes/tutorials/ex70.c
## Implementations
MatNestGetISs_Nest in src/mat/impls/nest/matnest.c
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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/mat/impls/nest/matnest.c)
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