petsc-3.9.4 2018-09-11

PCSetModifySubMatrices

Sets a user-defined routine for modifying the submatrices that arise within certain subdomain-based preconditioners. The basic submatrices are extracted from the preconditioner matrix as usual; the user can then alter these (for example, to set different boundary conditions for each submatrix) before they are used for the local solves.

Synopsis

#include "petscksp.h" 
PetscErrorCode  PCSetModifySubMatrices(PC pc,PetscErrorCode (*func)(PC,PetscInt,const IS[],const IS[],Mat[],void*),void *ctx)

Logically Collective on PC

Input Parameters

	pc	- the preconditioner context
	func	- routine for modifying the submatrices
	ctx	- optional user-defined context (may be null)

Calling sequence of func

    func (PC pc,PetscInt nsub,IS *row,IS *col,Mat *submat,void *ctx);

row -an array of index sets that contain the global row numbers that comprise each local submatrix

col -an array of index sets that contain the global column numbers that comprise each local submatrix

submat -array of local submatrices

ctx -optional user-defined context for private data for the user-defined func routine (may be null)

Notes

PCSetModifySubMatrices() MUST be called before KSPSetUp() and KSPSolve().

A routine set by PCSetModifySubMatrices() is currently called within the block Jacobi (PCBJACOBI) and additive Schwarz (PCASM) preconditioners. All other preconditioners ignore this routine.

Keywords

PC, set, modify, submatrices

Level

advanced

Location

src/ksp/pc/interface/precon.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages