MatGetRowIJ#
Returns the compressed row storage i and j indices for the local rows of a sparse matrix
Synopsis#
#include "petscmat.h" 
PetscErrorCode MatGetRowIJ(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 - 0 or 1 indicating we want the indices starting at 0 or 1 
- symmetric - - PETSC_TRUEor- PETSC_FALSEindicating the matrix data structure should be symmetrized
- inodecompressed - - PETSC_TRUEor- PETSC_FALSEindicating if the nonzero structure of the inodes or the nonzero elements is wanted. For- MATBAIJmatrices the compressed version is always used.
Output Parameters#
- n - number of local rows in the (possibly compressed) matrix, use - NULLif not needed
- ia - the row pointers; that is ia[0] = 0, ia[row] = ia[row-1] + number of elements in that row of the matrix, use - NULLif not needed
- ja - the column indices, use - NULLif not needed
- done - indicates if the routine actually worked and returned appropriate ia[] and ja[] arrays; callers are responsible for handling the case when done == - PETSC_FALSEand ia and ja are not set
Notes#
You CANNOT change any of the ia[] or ja[] values.
Use MatRestoreRowIJ() when you are finished accessing the ia[] and ja[] values.
Fortran Notes#
Use
    PetscInt, pointer :: ia(:),ja(:)
    call MatGetRowIJF90(mat,shift,symmetric,inodecompressed,n,ia,ja,done,ierr)
    ! Access the ith and jth entries via ia(i) and ja(j)
MatGetRowIJ() Fortran binding is deprecated (since PETSc 3.19), use MatGetRowIJF90()
See Also#
Matrices, Mat, MATAIJ, MatGetRowIJF90(), MatGetColumnIJ(), MatRestoreRowIJ(), MatSeqAIJGetArray()
Level#
developer
Location#
Implementations#
MatGetRowIJ_MPIAdj() in src/mat/impls/adj/mpi/mpiadj.c
MatGetRowIJ_MPIAIJ() in src/mat/impls/aij/mpi/mpiaij.c
MatGetRowIJ_SeqAIJ() in src/mat/impls/aij/seq/aij.c
MatGetRowIJ_SeqBAIJ() in src/mat/impls/baij/seq/baij.c
MatGetRowIJ_SeqSBAIJ() in src/mat/impls/sbaij/seq/sbaij.c
Index of all Mat routines
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Index of all manual pages