KSPGetConvergedReason#
Gets the reason the KSP iteration was stopped.
Synopsis#
#include "petscksp.h"
PetscErrorCode KSPGetConvergedReason(KSP ksp, KSPConvergedReason *reason)
Not Collective
Input Parameter#
ksp - the KSP context
Output Parameter#
reason - negative value indicates diverged, positive value converged, see KSPConvergedReason
Possible values for reason: See also manual page for each reason
KSP_CONVERGED_RTOL (residual 2-norm decreased by a factor of rtol, from 2-norm of right hand side)
KSP_CONVERGED_ATOL (residual 2-norm less than abstol)
KSP_CONVERGED_ITS (used by the preonly preconditioner that always uses ONE iteration, or when the KSPConvergedSkip() convergence test routine is set.
KSP_CONVERGED_CG_NEG_CURVE (see note below)
KSP_CONVERGED_CG_CONSTRAINED (see note below)
KSP_CONVERGED_STEP_LENGTH (see note below)
KSP_CONVERGED_ITERATING (returned if the solver is not yet finished)
KSP_DIVERGED_ITS (required more than its to reach convergence)
KSP_DIVERGED_DTOL (residual norm increased by a factor of divtol)
KSP_DIVERGED_NANORINF (residual norm became Not-a-number or Inf likely due to 0/0)
KSP_DIVERGED_BREAKDOWN (generic breakdown in method)
KSP_DIVERGED_BREAKDOWN_BICG (Initial residual is orthogonal to preconditioned initial residual. Try a different preconditioner, or a different initial Level.)
Options Database#
-ksp_converged_reason - prints the reason to standard out
Notes#
If this routine is called before or doing the KSPSolve() the value of KSP_CONVERGED_ITERATING is returned
The values KSP_CONVERGED_CG_NEG_CURVE, KSP_CONVERGED_CG_CONSTRAINED, and KSP_CONVERGED_STEP_LENGTH are returned only by the special KSPNASH, KSPSTCG, and KSPGLTR solvers which are used by the SNESNEWTONTR (trust region) solver.
See Also#
KSPSetConvergenceTest()
, KSPConvergedDefault()
, KSPSetTolerances()
, KSPConvergedReason
,
KSPConvergedReasonView()
Level#
intermediate
Location#
Examples#
src/dm/impls/stag/tutorials/ex4.c.html
src/dm/impls/stag/tutorials/ex8.c.html
src/ksp/pc/tutorials/ex1.c.html
src/ksp/pc/tutorials/ex2.c.html
src/ksp/ksp/tutorials/ex59.c.html
src/ksp/ksp/tutorials/ex72.c.html
src/ksp/ksp/tutorials/ex77.c.html
src/snes/tutorials/ex6.c.html
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages