SNESSetLagJacobianPersists#
Set whether or not the Jacobian lagging persists through multiple nonlinear solves
Synopsis#
#include "petscsnes.h"
PetscErrorCode SNESSetLagJacobianPersists(SNES snes, PetscBool flg)
Logically collective
Input Parameters#
snes - the
SNES
contextflg - jacobian lagging persists if true
Options Database Keys#
-snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
-snes_lag_jacobian <- 2,1,2,…> - sets the lag
-snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
-snes_lag_preconditioner <- 2,1,2,…> - sets the lag
Notes#
Normally when SNESSetLagJacobian()
is used, the Jacobian is always rebuilt at the beginning of each new nonlinear solve, this removes that.
This is useful both for nonlinear preconditioning, where it’s appropriate to have the Jacobian be stale by several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several timesteps may present huge efficiency gains.
See Also#
SNES: Nonlinear Solvers, SNES,
SNESSetLagPreconditionerPersists(),
SNESSetLagJacobian(),
SNESGetLagJacobian(),
SNESGetNPC(),
SNESSetLagJacobianPersists()`
Level#
advanced
Location#
Index of all SNES routines
Table of Contents for all manual pages
Index of all manual pages