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# MatGetTrace
Gets the trace of a matrix. The sum of the diagonal entries. 
## Synopsis
```
#include "petscmat.h" 
PetscErrorCode MatGetTrace(Mat mat, PetscScalar *trace)
```
Collective


## Input Parameter

- ***mat -*** the matrix



## Output Parameter

- ***trace -*** the sum of the diagonal entries





## See Also
 [](ch_matrices), `Mat`

## Level
advanced

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


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