MatGetColumnIJ — PETSc 3.24.5 documentation

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# MatGetColumnIJ

Returns the compressed column storage i and j indices for sequential matrices.

## Synopsis

    #include "petscmat.h"
    PetscErrorCode MatGetColumnIJ(Mat mat, PetscInt shift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)

Collective

## Input Parameters

- mat - the matrix

- shift - 1 or zero indicating we want the indices starting at 0 or 1

- symmetric - `PETSC_TRUE` or `PETSC_FALSE` indicating the matrix data structure should be symmetrized

- inodecompressed - `PETSC_TRUE` or `PETSC_FALSE` indicating if the nonzero structure of the inodes or the nonzero elements is wanted. For `MATBAIJ` matrices the compressed version is always used.

## Output Parameters

- n - number of columns in the (possibly compressed) matrix

- ia - the column pointers; that is ia[0] = 0, ia[col] = i[col-1] + number of elements in that col of the matrix

- ja - the row indices

- done - `PETSC_TRUE` or `PETSC_FALSE`, indicating whether the values have been returned

## See Also

Matrices, `Mat`, `MatGetRowIJ()`, `MatRestoreColumnIJ()`

## Level

developer

## Location

src/mat/interface/matrix.c

## Implementations

MatGetColumnIJ_SeqAIJ() in src/mat/impls/aij/seq/aij.c
MatGetColumnIJ_SeqBAIJ() in src/mat/impls/baij/seq/baij.c

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