VecGetOwnershipRanges#

Returns the range of indices owned by EACH processor, The vector is laid out with the first n1 elements on the first processor, next n2 elements on the second, etc. For certain parallel layouts this range may not be well defined.

Synopsis#

#include "petscvec.h"   
PetscErrorCode VecGetOwnershipRanges(Vec x, const PetscInt *ranges[])

Not Collective

Input Parameter#

  • x - the vector

Output Parameter#

  • ranges - array of length size + 1 with the start and end+1 for each process

Notes#

If the Vec was obtained from a DM with DMCreateGlobalVector(), then the range values are determined by the specific DM.

If the Vec was created directly the range values are determined by the local size passed to VecSetSizes() or VecCreateMPI(). If PETSC_DECIDE was passed as the local size, then the vector uses default values for the range using PetscSplitOwnership().

The high argument is one more than the last element stored locally.

For certain DM, such as DMDA, it is better to use DM specific routines, such as DMDAGetGhostCorners(), to determine the local values in the vector.

The high argument is one more than the last element stored locally.

If ranges are used after all vectors that share the ranges has been destroyed, then the program will crash accessing ranges.

Fortran Notes#

You must PASS in an array of length size + 1, where size is the size of the communicator owning the vector

See Also#

Vectors and Parallel Data, Vec, MatGetOwnershipRange(), MatGetOwnershipRanges(), VecGetOwnershipRange(), PetscSplitOwnership(), VecSetSizes(), VecCreateMPI(), PetscLayout, DMDAGetGhostCorners(), DM

Level#

beginner

Location#

src/vec/vec/interface/vector.c

Examples#

src/tao/pde_constrained/tutorials/elliptic.c

Index of all Vec routines
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Index of all manual pages