:orphan:
# MatIncreaseOverlap
Given a set of submatrices indicated by index sets, replaces the index sets by larger ones that represent submatrices with additional overlap.
## Synopsis
```
#include "petscmat.h"
PetscErrorCode MatIncreaseOverlap(Mat mat, PetscInt n, IS is[], PetscInt ov)
```
Collective
## Input Parameters
- ***mat -*** the matrix
- ***n -*** the number of index sets
- ***is -*** the array of index sets (these index sets will changed during the call)
- ***ov -*** the additional overlap requested
## Options Database Key
- ***-mat_increase_overlap_scalable -*** use a scalable algorithm to compute the overlap (supported by MPIAIJ matrix)
## Note
The computed overlap preserves the matrix block sizes when the blocks are square.
That is: if a matrix nonzero for a given block would increase the overlap all columns associated with
that block are included in the overlap regardless of whether each specific column would increase the overlap.
## See Also
[](ch_matrices), `Mat`, `PCASM`, `MatSetBlockSize()`, `MatIncreaseOverlapSplit()`, `MatCreateSubMatrices()`
## Level
developer
## Location
src/mat/interface/matrix.c
## Examples
src/ksp/ksp/tutorials/ex82.c
## Implementations
MatIncreaseOverlap_MPIAIJ in src/mat/impls/aij/mpi/mpiov.c
MatIncreaseOverlap_SeqAIJ in src/mat/impls/aij/seq/aij.c
MatIncreaseOverlap_MPIBAIJ in src/mat/impls/baij/mpi/baijov.c
MatIncreaseOverlap_SeqBAIJ in src/mat/impls/baij/seq/baij2.c
MatIncreaseOverlap_Htool in src/mat/impls/htool/htool.cxx
MatIncreaseOverlap_IS in src/mat/impls/is/matis.c
MatIncreaseOverlap_Normal in src/mat/impls/normal/normm.c
MatIncreaseOverlap_MPISBAIJ in src/mat/impls/sbaij/mpi/sbaijov.c
MatIncreaseOverlap_SeqSBAIJ in src/mat/impls/sbaij/seq/sbaij2.c
---
[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/mat/interface/matrix.c)
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