petsc3.15.0 20210405
VecISAXPY
Adds a reduced vector to the appropriate elements of a fullspace vector. vfull[is[i]] += alpha*vreduced[i]
Synopsis
#include "petscvec.h"
PetscErrorCode VecISAXPY(Vec vfull, IS is, PetscScalar alpha, Vec vreduced)
Input Parameters
 vfull   the fullspace vector

 is   the index set for the reduced space

 alpha   the scalar coefficient

 vreduced   the reducedspace vector

Output Parameters
 vfull   the sum of the fullspace vector and reducedspace vector

Notes
The index set identifies entries in the global vector.
Negative indices are skipped; indices outside the ownership range of vfull will raise an error.
See Also
VecAXPY(), VecGetOwnershipRange()
Level
advanced
Location
src/vec/vec/utils/projection.c
Index of all Vec routines
Table of Contents for all manual pages
Index of all manual pages