TSSetTolerances

Set tolerances for local truncation error when using an adaptive controller

Synopsis

#include "petscts.h"  
PetscErrorCode TSSetTolerances(TS ts, PetscReal atol, Vec vatol, PetscReal rtol, Vec vrtol)

Logically Collective

Input Parameters

• ts - time integration context

• atol - scalar absolute tolerances

• vatol - vector of absolute tolerances or NULL, used in preference to atol if present

• rtol - scalar relative tolerances

• vrtol - vector of relative tolerances or NULL, used in preference to rtol if present

Options Database Keys

• -ts_rtol - relative tolerance for local truncation error

• -ts_atol - Absolute tolerance for local truncation error

Notes

PETSC_CURRENT or PETSC_DETERMINE may be used for atol or rtol to indicate the current value or the default value from when the object’s type was set.

With PETSc’s implicit schemes for DAE problems, the calculation of the local truncation error (LTE) includes both the differential and the algebraic variables. If one wants the LTE to be computed only for the differential or the algebraic part then this can be done using the vector of tolerances vatol. For example, by setting the tolerance vector with the desired tolerance for the differential part and infinity for the algebraic part, the LTE calculation will include only the differential variables.

Fortran Note

Use PETSC_CURRENT_INTEGER or PETSC_DETERMINE_INTEGER.

See Also

TS: Scalable ODE and DAE Solvers, TS, TSAdapt, TSErrorWeightedNorm(), TSGetTolerances()

Level

beginner

Location

src/ts/interface/ts.c

Examples

src/tao/unconstrained/tutorials/burgers_spectral.c
src/tao/unconstrained/tutorials/spectraladjointassimilation.c
src/ts/tutorials/ex49.c
src/ts/tutorials/ex50.c
src/ts/tutorials/ex30.c

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