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SNESSetLagPreconditioner

Determines when the preconditioner is rebuilt in the nonlinear solve.

Synopsis

#include "petscsnes.h"  
PetscErrorCode  SNESSetLagPreconditioner(SNES snes,PetscInt lag)
Logically Collective on SNES

Input Parameters

snes - the SNES context
lag - 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_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

The default is 1 The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or SNESSetLagPreconditionerPersists() was called

SNESSetLagPreconditionerPersists() allows using the same uniform lagging (for example every second solve) across multiple solves.

See Also

SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESSetLagPreconditionerPersists(),
SNESSetLagJacobianPersists()

Level

intermediate

Location

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