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# MatMPIAIJGetSeqAIJ

Returns the local pieces of this distributed matrix

## Synopsis

    #include "petscmat.h"
    PetscErrorCode MatMPIAIJGetSeqAIJ(Mat A, Mat *Ad, Mat *Ao, const PetscInt *colmap[])

Not Collective

## Input Parameter

- A - The `MATMPIAIJ` matrix

## Output Parameters

- Ad - The local diagonal block as a `MATSEQAIJ` matrix

- Ao - The local off-diagonal block as a `MATSEQAIJ` matrix

- colmap - An array mapping local column numbers of `Ao` to global column numbers of the parallel matrix

## Note

The rows in `Ad` and `Ao` are in [0, Nr), where Nr is the number of local rows on this process. The columns in `Ad` are in [0, Nc) where Nc is the number of local columns. The columns are `Ao` are in [0, Nco), where Nco is the number of nonzero columns in the local off-diagonal piece of the matrix `A`. The array colmap maps these local column numbers to global column numbers in the original matrix.

## Fortran Notes

`MatMPIAIJGetSeqAIJ()` Fortran binding is deprecated (since PETSc 3.19), use `MatMPIAIJGetSeqAIJF90()`

## See Also

Matrices, `Mat`, `MATMPIAIJ`, `MatMPIAIJGetSeqAIJF90()`, `MatMPIAIJRestoreSeqAIJF90()`, `MatMPIAIJGetLocalMat()`, `MatMPIAIJGetLocalMatCondensed()`, `MatCreateAIJ()`, `MATSEQAIJ`

## Level

intermediate

## Location

src/mat/impls/aij/mpi/mpiaij.c

## Examples

src/ksp/ksp/tutorials/ex19.c
src/mat/tutorials/ex8.c

Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages