DMDAGetProcessorSubset#

Returns a communicator consisting only of the processors in a DMDA that own a particular global x, y, or z grid point (corresponding to a logical plane in a 3D grid or a line in a 2D grid).

Synopsis#

#include "petscdmda.h"   
PetscErrorCode DMDAGetProcessorSubset(DM da, DMDirection dir, PetscInt gp, MPI_Comm *comm)

Collective; No Fortran Support

Input Parameters#

da - the distributed array
dir - Cartesian direction, either DM_X, DM_Y, or DM_Z
gp - global grid point number in this direction

Output Parameter#

comm - new communicator

Notes#

All processors that share the DMDA must call this with the same gp value

After use, comm should be freed with MPI_Comm_free()

This routine is particularly useful to compute boundary conditions or other application-specific calculations that require manipulating sets of data throughout a logical plane of grid points.