petsc-3.7.5 2017-01-01

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

 KSP_CONVERGED_CG_CONSTRAINED

 KSP_CONVERGED_STEP_LENGTH

 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.)

Notes: Can only be called after the call the KSPSolve() is complete.

Keywords

KSP, nonlinear, set, convergence, test

Examples