# 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#

the matrix**mat -**the number of index sets**n -**the array of index sets (these index sets will changed during the call)**is -**the additional overlap requested**ov -**

## Options Database Key#

use a scalable algorithm to compute the overlap (supported by MPIAIJ matrix)**-mat_increase_overlap_scalable -**

## 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#

Matrices, `Mat`

, `PCASM`

, `MatSetBlockSize()`

, `MatIncreaseOverlapSplit()`

, `MatCreateSubMatrices()`

## Level#

developer

## Location#

## Examples#

## 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

Index of all Mat routines

Table of Contents for all manual pages

Index of all manual pages