petsc-3.14.6 2021-03-30
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SNESSetLagJacobianPersists

 Set whether or not the Jacobian lagging persists through multiple solves

Synopsis

#include "petscsnes.h"  
PetscErrorCode  SNESSetLagJacobianPersists(SNES snes,PetscBool flg)
Logically collective on SNES

Input Parameter

snes - the SNES context
flg - jacobian lagging persists if true

Options Database Keys

-snes_lag_jacobian_persists <true,false> - sets the persistence
-snes_lag_jacobian <- 2,1,2,...> - sets the lag
-snes_lag_preconditioner_persists <true,false> - sets the persistence
-snes_lag_preconditioner <- 2,1,2,...> - sets the lag

Notes

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

SNESSetLagPreconditionerPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC(), SNESSetLagJacobianPersists()

Level

developer

Location

src/snes/interface/snes.c
Index of all SNES routines
Table of Contents for all manual pages
Index of all manual pages