MatGetOwnershipRange#
For matrices that own values by row, excludes MATELEMENTAL and MATSCALAPACK, returns the range of matrix rows owned by this MPI rank. For all matrices it returns the range of matrix rows associated with rows of a vector that would contain the result of a matrix vector product with this matrix. See Matrix Layouts for details on matrix layouts
Synopsis#
#include "petscmat.h"
PetscErrorCode MatGetOwnershipRange(Mat mat, PetscInt *m, PetscInt *n)
Not Collective
Input Parameter#
mat - the matrix
Output Parameters#
m - the global index of the first local row, use
NULLto not obtain this valuen - one more than the global index of the last local row, use
NULLto not obtain this value
Note#
This function requires that the matrix be preallocated. If you have not preallocated, consider using
PetscSplitOwnership(MPI_Comm comm, PetscInt *n, PetscInt *N)
and then MPI_Scan() to calculate prefix sums of the local sizes.
See Also#
Matrices, Mat, MatGetOwnershipRanges(), MatGetOwnershipRangeColumn(), MatGetOwnershipRangesColumn(), PetscSplitOwnership(), PetscSplitOwnershipBlock(),
PetscLayout
Level#
beginner
Location#
Examples#
src/ksp/ksp/tutorials/bench_kspsolve.c
src/ksp/ksp/tutorials/ex11.c
src/ksp/ksp/tutorials/ex11f.F90
src/ksp/ksp/tutorials/ex12.c
src/ksp/ksp/tutorials/ex15.c
src/ksp/ksp/tutorials/ex15f.F90
src/ksp/ksp/tutorials/ex16.c
src/ksp/ksp/tutorials/ex18.c
src/ksp/ksp/tutorials/ex19.c
src/ksp/ksp/tutorials/ex2.c
src/ksp/ksp/tutorials/ex2f.F90
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages