:orphan:
# MATAIJ
MATAIJ = "aij" - A matrix type to be used for sparse matrices. This matrix type is identical to `MATSEQAIJ` when constructed with a single process communicator,
and `MATMPIAIJ` otherwise.  As a result, for single process communicators,
`MatSeqAIJSetPreallocation()` is supported, and similarly `MatMPIAIJSetPreallocation()` is supported
for communicators controlling multiple processes.  It is recommended that you call both of
the above preallocation routines for simplicity.


## Options Database Key

- ***-mat_type aij -*** sets the matrix type to "aij" during a call to `MatSetFromOptions()`





## Note
Subclasses include `MATAIJCUSPARSE`, `MATAIJPERM`, `MATAIJSELL`, `MATAIJMKL`, `MATAIJCRL`, and also automatically switches over to use inodes when
enough exist.


## See Also
 [](ch_matrices), `Mat`, `MatCreateAIJ()`, `MatCreateSeqAIJ()`, `MATSEQAIJ`, `MATMPIAIJ`, `MATSELL`, `MATSEQSELL`, `MATMPISELL`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/seq/aij.c.html#MATAIJ">src/mat/impls/aij/seq/aij.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/tutorials/ex14.c.html">src/dm/tutorials/ex14.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/ex34.c.html">src/ksp/ksp/tutorials/ex34.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex4.c.html">src/ksp/ksp/tutorials/ex4.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex42.c.html">src/ksp/ksp/tutorials/ex42.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex43.c.html">src/ksp/ksp/tutorials/ex43.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex44f.F90.html">src/ksp/ksp/tutorials/ex44f.F90</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex49.c.html">src/ksp/ksp/tutorials/ex49.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex52f.F90.html">src/ksp/ksp/tutorials/ex52f.F90</A><BR>
<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>


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


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