petsc-3.14.6 2021-03-30

MatPreallocateLocation

An alternative to MatPreallocateSet() that puts the nonzero locations into the matrix if it exists

#include <petscmat.h>
PetscErrorCode MatPreallocateLocations(Mat A,PetscInt row,PetscInt ncols,PetscInt *cols,PetscInt *dnz,PetscInt *onz)

Not Collective

	A	- matrix
	row	- row where values exist (must be local to this process)
	ncols	- number of columns
	cols	- columns with nonzeros
	dnz	- the array that will be passed to the matrix preallocation routines
	onz	- the other array passed to the matrix preallocation routines

See Users-Manual: ch_performance for more details.

Do not malloc or free dnz and onz that is handled internally by these routines

This is a MACRO not a function because it uses a bunch of variables private to the MatPreallocation.... routines.

intermediate