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# MATSEQSBAIJ
MATSEQSBAIJ = "seqsbaij" - A matrix type to be used for sequential symmetric block sparse matrices, based on block compressed sparse row format.  Only the upper triangular portion of the matrix is stored. For complex numbers by default this matrix is symmetric, NOT Hermitian symmetric. To make it Hermitian symmetric you
can call `MatSetOption`(`Mat`, `MAT_HERMITIAN`).


## Options Database Key
. -mat_type seqsbaij - sets the matrix type to "seqsbaij" during a call to `MatSetFromOptions()`




## Notes
By default if you insert values into the lower triangular part of the matrix they are simply ignored (since they are not
stored and it is assumed they symmetric to the upper triangular). If you call `MatSetOption`(`Mat`,`MAT_IGNORE_LOWER_TRIANGULAR`,`PETSC_FALSE`) or use
the options database `-mat_ignore_lower_triangular` false it will generate an error if you try to set a value in the lower triangular portion.

The number of rows in the matrix must be less than or equal to the number of columns


## See Also
 [](ch_matrices), `Mat`, `MATSEQSBAIJ`, `MatCreateSeqSBAIJ()`, `MatType`, `MATMPISBAIJ`

## Level
beginner

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


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