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# MatSetBlockSizesFromMats
Sets the matrix block row and column sizes to match a pair of matrices 
## Synopsis
```
#include "petscmat.h" 
PetscErrorCode MatSetBlockSizesFromMats(Mat mat, Mat fromRow, Mat fromCol)
```
Logically Collective


## Input Parameters

- ***mat -*** the matrix
- ***fromRow -*** matrix from which to copy row block size
- ***fromCol -*** matrix from which to copy column block size (can be same as fromRow)





## See Also
 [](ch_matrices), `Mat`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSizes()`

## Level
developer

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

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex76.c.html">src/ksp/ksp/tutorials/ex76.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex76f.F90.html">src/ksp/ksp/tutorials/ex76f.F90</A><BR>


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