petsc-3.9.4 2018-09-11
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VecGetValues

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

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

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

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

VecAssemblyBegin(), VecAssemblyEnd(), VecSetValues()

Level

beginner

Location

src/vec/vec/interface/rvector.c

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