petsc-3.7.5 2017-01-01

KSPSetConvergenceTest

Sets the function to be used to determine convergence.

Synopsis

#include "petscksp.h" 
PetscErrorCode  KSPSetConvergenceTest(KSP ksp,PetscErrorCode (*converge)(KSP,PetscInt,PetscReal,KSPConvergedReason*,void*),void *cctx,PetscErrorCode (*destroy)(void*))

Logically Collective on KSP

Input Parameters

	ksp	- iterative context obtained from KSPCreate()
	converge	- pointer to int function
	cctx	- context for private data for the convergence routine (may be null)
	destroy	- a routine for destroying the context (may be null)

Calling sequence of converge

    converge (KSP ksp, int it, PetscReal rnorm, KSPConvergedReason *reason,void *mctx)

	ksp	- iterative context obtained from KSPCreate()
	it	- iteration number
	rnorm	- (estimated) 2-norm of (preconditioned) residual
	reason	- the reason why it has converged or diverged
	cctx	- optional convergence context, as set by KSPSetConvergenceTest()

Notes

Must be called after the KSP type has been set so put this after a call to KSPSetType(), or KSPSetFromOptions().

The default convergence test, KSPConvergedDefault(), aborts if the residual grows to more than 10000 times the initial residual.

The default is a combination of relative and absolute tolerances. The residual value that is tested may be an approximation; routines that need exact values should compute them.

In the default PETSc convergence test, the precise values of reason are macros such as KSP_CONVERGED_RTOL, which are defined in petscksp.h.

Keywords

KSP, set, convergence, test, context

Examples

src/ksp/ksp/examples/tutorials/ex2f.F.html