petsc-3.3-p7 2013-05-11

SNESGetLagPreconditioner

Indicates how often the preconditioner is rebuilt

Synopsis

#include "petscsnes.h"  
#include "petscdmshell.h" 
#include "petscsys.h" 
PetscErrorCode  SNESGetLagPreconditioner(SNES snes,PetscInt *lag)

Not Collective

Input Parameter

snes -the SNES context

Output Parameter

lag --1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

Options Database Keys

-snes_lag_preconditioner <lag> - Notes: The default is 1 The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

Keywords