VecGetSubVector#

Gets a vector representing part of another vector

Synopsis#

#include "petscvec.h"   
PetscErrorCode VecGetSubVector(Vec X, IS is, Vec *Y)

Collective

Input Parameters#

  • X - vector from which to extract a subvector

  • is - index set representing portion of X to extract

Output Parameter#

  • Y - subvector corresponding to is

Notes#

The subvector Y should be returned with VecRestoreSubVector(). X and is must be defined on the same communicator

Changes to the subvector will be reflected in the X vector on the call to VecRestoreSubVector().

This function may return a subvector without making a copy, therefore it is not safe to use the original vector while modifying the subvector. Other non-overlapping subvectors can still be obtained from X using this function.

The resulting subvector inherits the block size from is if greater than one. Otherwise, the block size is guessed from the block size of the original X.

See Also#

Vectors and Parallel Data, Vec, IS, VECNEST, MatCreateSubMatrix()

Level#

advanced

Location#

src/vec/vec/interface/rvector.c

Examples#

src/snes/tutorials/ex63.c
src/ksp/ksp/tutorials/ex81.c
src/vec/vec/tutorials/ex44.c
src/ts/tutorials/ex77.c
src/snes/tutorials/ex70.c
src/dm/tutorials/ex22.c

Implementations#

VecGetSubVector_MPIKokkos() in src/vec/vec/impls/mpi/kokkos/mpikok.kokkos.cxx
VecGetSubVector_Nest() in src/vec/vec/impls/nest/vecnest.c
VecGetSubVector_SeqKokkos() in src/vec/vec/impls/seq/kokkos/veckok.kokkos.cxx


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