petsc-3.12.5 2020-03-29

VecSetValues

Inserts or adds values into certain locations of a vector.

Synopsis

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

Not Collective

Input Parameters

	x	- vector to insert in
	ni	- number of elements to add
	ix	- indices where to add
	y	- array of values
	iora	- either INSERT_VALUES or ADD_VALUES, where ADD_VALUES adds values to any existing entries, and INSERT_VALUES replaces existing entries with new values

Notes

VecSetValues() sets x[ix[i]] = y[i], for i=0,...,ni-1.

Calls to VecSetValues() with the INSERT_VALUES and ADD_VALUES options cannot be mixed without intervening calls to the assembly routines.

These values may be cached, so VecAssemblyBegin() and VecAssemblyEnd() MUST be called after all calls to VecSetValues() have been completed.

VecSetValues() 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. This allows easily inserting element load matrices with homogeneous Dirchlet boundary conditions that you don't want represented in the vector.

Level

beginner

VecSetValues

Synopsis

Input Parameters

Notes

See Also

Level

Location

Examples

Implementations