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# MATSEQAIJ
MATSEQAIJ = "seqaij" - A matrix type to be used for sequential sparse matrices, based on compressed sparse row format. 
## Options Database Key

- ***-mat_type seqaij -*** sets the matrix type to "seqaij" 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


## Developer Note
It would be nice if all matrix formats supported passing `NULL` in for the numerical values


## See Also
 [](ch_matrices), `Mat`, `MatCreateSeqAIJ()`, `MatSetFromOptions()`, `MatSetType()`, `MatCreate()`, `MatType`, `MATSELL`, `MATSEQSELL`, `MATMPISELL`

## Level
beginner

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

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex59.c.html">src/ksp/ksp/tutorials/ex59.c</A><BR>
<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/ex83f.F90.html">src/ksp/ksp/tutorials/ex83f.F90</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/tutorials/ex1.c.html">src/mat/tutorials/ex1.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/tutorials/ex12.c.html">src/mat/tutorials/ex12.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/tutorials/ex5cu.cu.html">src/mat/tutorials/ex5cu.cu</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/leastsquares/tutorials/tomography.c.html">src/tao/leastsquares/tutorials/tomography.c</A><BR>


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


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