:orphan:
# MatGetOwnershipRange
For matrices that own values by row, excludes `MATELEMENTAL` and `MATSCALAPACK`, returns the range of matrix rows owned by this MPI rank. For all matrices  it returns the range of matrix rows associated with rows of a vector that would contain the result of a matrix vector product with this matrix. See [Matrix Layouts](sec_matlayout) for details on matrix layouts 
## Synopsis
```
#include "petscmat.h" 
PetscErrorCode MatGetOwnershipRange(Mat mat, PetscInt *m, PetscInt *n)
```
Not Collective


## Input Parameter

- ***mat -*** the matrix



## Output Parameters

- ***m -*** the global index of the first local row, use `NULL` to not obtain this value
- ***n -*** one more than the global index of the last local row, use `NULL` to not obtain this value





## Note
This function requires that the matrix be preallocated. If you have not preallocated, consider using
`PetscSplitOwnership`(`MPI_Comm` comm, `PetscInt` *n, `PetscInt` *N)
and then `MPI_Scan()` to calculate prefix sums of the local sizes.


## See Also
 [](ch_matrices), `Mat`, `MatGetOwnershipRanges()`, `MatGetOwnershipRangeColumn()`, `MatGetOwnershipRangesColumn()`, `PetscSplitOwnership()`, `PetscSplitOwnershipBlock()`,
`PetscLayout`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/interface/matrix.c.html#MatGetOwnershipRange">src/mat/interface/matrix.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/bench_kspsolve.c.html">src/ksp/ksp/tutorials/bench_kspsolve.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex11.c.html">src/ksp/ksp/tutorials/ex11.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex11f.F90.html">src/ksp/ksp/tutorials/ex11f.F90</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex12.c.html">src/ksp/ksp/tutorials/ex12.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex15.c.html">src/ksp/ksp/tutorials/ex15.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex15f.F90.html">src/ksp/ksp/tutorials/ex15f.F90</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex16.c.html">src/ksp/ksp/tutorials/ex16.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex18.c.html">src/ksp/ksp/tutorials/ex18.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex19.c.html">src/ksp/ksp/tutorials/ex19.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex2.c.html">src/ksp/ksp/tutorials/ex2.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex2f.F90.html">src/ksp/ksp/tutorials/ex2f.F90</A><BR>


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[Index of all Mat routines](index.md)  
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[Index of all manual pages](/manualpages/singleindex.md)