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# MATMPIAIJ
MATMPIAIJ = "mpiaij" - A matrix type to be used for parallel sparse matrices. 
## Options Database Keys

- ***-mat_type mpiaij -*** sets the matrix type to `MATMPIAIJ` during a call to `MatSetFromOptions()`





## Notes
`MatSetValues()` may be called for this matrix type with a `NULL` argument for the numerical values,
in this case the values associated with the rows and columns one passes in are set to zero
in the matrix

`MatSetOptions`(,`MAT_STRUCTURE_ONLY`,`PETSC_TRUE`) may be called for this matrix type. In this no
space is allocated for the nonzero entries and any entries passed with `MatSetValues()` are ignored


## See Also
 [](ch_matrices), `Mat`, `MATSEQAIJ`, `MATAIJ`, `MatCreateAIJ()`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/mpi/mpiaij.c.html#MATMPIAIJ">src/mat/impls/aij/mpi/mpiaij.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex54.c.html">src/ksp/ksp/tutorials/ex54.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex54f.F90.html">src/ksp/ksp/tutorials/ex54f.F90</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex70.c.html">src/snes/tutorials/ex70.c</A><BR>


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