VecGetValues#

Gets values from certain locations of a vector. Currently can only get values on the same processor on which they are owned

Synopsis#

#include "petscvec.h"   
PetscErrorCode VecGetValues(Vec x, PetscInt ni, const PetscInt ix[], PetscScalar y[])

Not Collective

Input Parameters#

  • x - vector to get values from

  • ni - number of elements to get

  • ix - indices where to get them from (in global 1d numbering)

Output Parameter#

  • y - array of values, must be passed in with a length of ni

Notes#

The user provides the allocated array y; it is NOT allocated in this routine

VecGetValues() gets y[i] = x[ix[i]], for i=0,…,ni-1.

VecAssemblyBegin() and VecAssemblyEnd() MUST be called before calling this if VecSetValues() or related routine has been called

VecGetValues() uses 0-based indices in Fortran as well as in C.

If you call VecSetOption(x, VEC_IGNORE_NEGATIVE_INDICES,PETSC_TRUE), negative indices may be passed in ix. These rows are simply ignored.

See Also#

Vectors and Parallel Data, Vec, VecAssemblyBegin(), VecAssemblyEnd(), VecSetValues()

Level#

beginner

Location#

src/vec/vec/interface/rvector.c

Examples#

src/vec/vec/tutorials/ex2f.F90

Implementations#

VecGetValues_MPI() in src/vec/vec/impls/mpi/pdvec.c
VecGetValues_Seq() in src/vec/vec/impls/seq/bvec2.c


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