petsc-3.7.5 2017-01-01

VecGetSubVector

Gets a vector representing part of another vector

Synopsis

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

Collective on IS (and Vec if nonlocal entries are needed)

Input Arguments

	X	- vector from which to extract a subvector
	is	- index set representing portion of X to extract

Output Arguments

Y -subvector corresponding to is

Notes

The subvector Y should be returned with 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.

Examples