MatIncreaseOverlap#

Given a set of submatrices indicated by index sets, replaces the index sets by larger ones that represent submatrices with additional overlap.

Synopsis#

#include "petscmat.h" 
PetscErrorCode MatIncreaseOverlap(Mat mat, PetscInt n, IS is[], PetscInt ov)

Collective

Input Parameters#

mat - the matrix
n - the number of index sets
is - the array of index sets (these index sets will changed during the call)
ov - the additional overlap requested

Options Database Key#

-mat_increase_overlap_scalable - use a scalable algorithm to compute the overlap (supported by MPIAIJ matrix)

Note#

The computed overlap preserves the matrix block sizes when the blocks are square. That is: if a matrix nonzero for a given block would increase the overlap all columns associated with that block are included in the overlap regardless of whether each specific column would increase the overlap.