SNESGetLagJacobian#

Get how often the Jacobian is rebuilt. See SNESGetLagPreconditioner() to determine when the preconditioner is rebuilt

Synopsis#

#include "petscsnes.h"  
PetscErrorCode SNESGetLagJacobian(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.

Notes#

The default is 1

The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or SNESSetLagJacobianPersists() was called.

See Also#

SNES: Nonlinear Solvers, SNES, SNESSetTrustRegionTolerance(), SNESSetLagJacobian(), SNESSetLagPreconditioner(), SNESGetLagPreconditioner(), SNESSetLagJacobianPersists(), SNESSetLagPreconditionerPersists()

Level#

intermediate

Location#

src/snes/interface/snes.c

Index of all SNES routines
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Index of all manual pages