# MATBAIJ
MATBAIJ = "baij" - A matrix type to be used for block sparse matrices. This matrix type is identical to `MATSEQBAIJ` when constructed with a single process communicator,
and `MATMPIBAIJ` otherwise.


## Options Database Keys

- ***-mat_type baij -*** sets the matrix type to `MATBAIJ` during a call to `MatSetFromOptions()`





## See Also
 `Mat`, `MatCreateBAIJ()`, `MATSEQBAIJ`, `MATMPIBAIJ`, `MatMPIBAIJSetPreallocation()`, `MatMPIBAIJSetPreallocationCSR()`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/baij/mpi/mpibaij.c.html#MATBAIJ">src/mat/impls/baij/mpi/mpibaij.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex35.cxx.html">src/ts/tutorials/ex35.cxx.html</A><BR>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/mat/impls/baij/mpi/mpibaij.c)


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