KSPSetTolerances

Sets the relative, absolute, divergence, and maximum iteration tolerances used by the default KSP convergence testers.

Synopsis

int KSPSetTolerances(KSP ksp,double rtol,double atol,double dtol,int maxits)
Collective on KSP

Input Parameters

ksp - the Krylov subspace context
rtol - the relative convergence tolerance (relative decrease in the residual norm)
atol - the absolute convergence tolerance (absolute size of the residual norm)
dtol - the divergence tolerance (amount residual can increase before KSPDefaultConverged concludes that the method is diverging)
maxits - maximum number of iterations to use

Options Database Keys

-ksp_atol <atol> - Sets atol
-ksp_rtol <rtol> - Sets rtol
-ksp_divtol <dtol> - Sets dtol
-ksp_max_it <maxits> - Sets maxits

Notes

Use PETSC_DEFAULT to retain the default value of any of the tolerances.

See KSPDefaultConverged() for details on the use of these parametersin the default convergence test. See also KSPSetConvergenceTest() for setting user-defined stopping criteria.

Keywords

KSP, set, tolerance, absolute, relative, divergence,
convergence, maximum, iterations

See Also

KSPGetTolerances(), KSPDefaultConverged(), KSPSetConvergenceTest()

Examples

src/sles/examples/tutorials/ex1f.F
src/sles/examples/tutorials/ex2f.F
src/sles/examples/tutorials/ex13f.F
src/sles/examples/tutorials/ex15f.F
src/sles/examples/tutorials/ex1.c
src/sles/examples/tutorials/ex2.c
src/sles/examples/tutorials/ex3.c
src/sles/examples/tutorials/ex7.c
src/sles/examples/tutorials/ex13.c
src/sles/examples/tutorials/ex15.c
src/snes/examples/tutorials/ex1f.F
src/snes/examples/tutorials/ex1.c

Location: src/ksp/interface/itfunc.c
KSP Index
Table of Contents