petsc-3.8.4 2018-03-24

DMSubDomainHookAdd

adds a callback to be run when restricting a problem to the coarse grid

Synopsis

#include "petscdm.h"          
#include "petscdmlabel.h"     
#include "petscds.h"     
PetscErrorCode DMSubDomainHookAdd(DM global,PetscErrorCode (*ddhook)(DM,DM,void*),PetscErrorCode (*restricthook)(DM,VecScatter,VecScatter,DM,void*),void *ctx)

Logically Collective

Input Arguments

	global	- global DM
	ddhook	- function to run to pass data to the decomposition DM upon its creation
	restricthook	- function to run to update data on block solve (at the beginning of the block solve)
	ctx	- [optional] user-defined context for provide data for the hooks (may be NULL)

Calling sequence for ddhook

   ddhook(DM global,DM block,void *ctx)

	global	- global DM
	block	- block DM
	ctx	- optional user-defined function context

Calling sequence for restricthook

   restricthook(DM global,VecScatter out,VecScatter in,DM block,void *ctx)

	global	- global DM
	out	- scatter to the outer (with ghost and overlap points) block vector
	in	- scatter to block vector values only owned locally
	block	- block DM
	ctx	- optional user-defined function context

Notes

This function is only needed if auxiliary data needs to be set up on subdomain DMs.

If this function is called multiple times, the hooks will be run in the order they are added.

In order to compose with nonlinear preconditioning without duplicating storage, the hook should be implemented to extract the global information from its context (instead of from the SNES).