TSPseudoComputeFunction#

Compute nonlinear residual for pseudo-timestepping

Synopsis#

#include "petscts.h"   
PetscErrorCode TSPseudoComputeFunction(TS ts, Vec solution, Vec *residual, PetscReal *fnorm)

This computes the residual for \(\dot U = 0\), i.e. \(F(U, 0)\) for the IFunction.

Collective

Input Parameters#

ts - the timestep context
solution - the solution vector

Output Parameter#

residual - the nonlinear residual
fnorm - the norm of the nonlinear residual

Note#

TSPSEUDO records the nonlinear residual and the solution vector used to generate it. If given the same solution vector (as determined by the vector’s PetscObjectState), this function will return those recorded values.

This can be used in a custom adaptive timestepping implementation that needs access to the residual, but can reuse the calculation already done by TSPSEUDO.

To correctly get the residual reuse behavior, solution must be the same Vec that was returned by TSGetSolution() or the Vec given by TSAdaptCheckStage().

Level#

advanced

Location#

src/ts/impls/pseudo/posindep.c

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