Dmitry,
I haven't heard back from you on this. Any thoughts?
Barry
> On Apr 20, 2015, at 6:23 PM, Barry Smith <[email protected]> wrote:
>
>
> Dmitry,
>
> Rather than introducing another whole complexity of flags for indicating
> domain errors in user functions just do the following.
>
> 1) just stick a Nan into the functions result
> 2) remove the VecValidValues() at the END of routines like MatMult()
> 3) when Nan or Inf pop up in Krylov methods (which will happen within
> VecNorm or VecDot() and thus we get free collective knowledge of the problem
> even if it happened on only one node), generate the appropriate
> KSP_DIVERGED_NANORINF. This is already handled sometimes (most of the time?),
> for example in KSPSolve_CG is code
> ierr = VecXDot(Z,R,&beta);CHKERRQ(ierr); /* beta <- z'*r */
> if (PetscIsInfOrNanScalar(beta)) {
> if (ksp->errorifnotconverged)
> SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_NOT_CONVERGED,"KSPSolve
> has not converged due to Nan or Inf inner product");
> else {
> ksp->reason = KSP_DIVERGED_NANORINF;
> PetscFunctionReturn(0);
> }
> }
>
> 4) SNES already handles failed to converge KSP and
> 5 ) TS already handles failed to converged SNES; by, for example, cutting
> the timestep.
>
> Barry
>
>
