PCSetModifySubMatrices#
Sets a user-defined routine for modifying the submatrices that arise within certain subdomain-based preconditioners such as PCASM
Synopsis#
#include "petscksp.h" 
PetscErrorCode PCSetModifySubMatrices(PC pc, PetscErrorCode (*func)(PC pc, PetscInt nsub, const IS row[], const IS col[], Mat submat[], void *ctx), void *ctx)
Logically Collective
Input Parameters#
- pc - the - PCpreconditioner context
- func - routine for modifying the submatrices 
- ctx - optional user-defined context (may be - NULL)
Calling sequence of func#
- pc - the - PCpreconditioner context
- nsub - number of index sets 
- 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#
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.
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.
See Also#
KSP: Linear System Solvers, PC, PCBJACOBI, PCASM, PCModifySubMatrices()
Level#
advanced
Location#
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages