[petsc-users] SNESSetConvergenceTest usage?

[Barry Smith]

> On Oct 7, 2015, at 5:12 PM, William Coirier <William.Coirier at kratosdefense.com> wrote:
> 
> Without going into too many details regarding the application, here is a problem I’ve encountered and wonder if anyone has any suggestions.
>  
> I have supplied a convergence test function for SNES using the SNESSetConvergenceTest API. My convergence test function sets the SNESConvergedReason variable referenced in the argument list to a handful of SNESConvergedReasons (and does other stuff, but that is not relevant…)
>  
> In my application code, after I call SNESSolve, I call SNESGetConvergedReason, and for some reason I will occasionally see SNESConvergedReasons that are NOT in the subset of those I supply with my convergence test function.
>  
> It’s as if my test function setting of the converged reason is either being overwritten, or ignored.
>  
> As an example, I’m using the newtonls (default) scheme, and (an inexact, but workable) Jacobian. My test function only will set SNESConvergedReason to SNES_CONVERGED_ITERATING, SNES_CONVERGED_SNORM_RELATIVE or SNES_DIVERGED_MAX_IT. But, I see DIVERGED_LINE_SEARCH from the call to SNESGetConvergedReason.

   The line search routines themselves can set the converged reason, when the line search fails, this happens before it has the next solution so before the next time your line search tester is called. So your value is not been overwritten or ignored. 

   I am not sure what you want to do about this? It is just the way it is.

  Barry

>  
> Is the line search diverging (most likely?!) and blowing by my convergence test function?? Maybe (most likely?) I’m doing something stupid…
>  
> Otherwise things are working great. PETSc is awesome!
>  
> Any help/suggestions/input is appreciated.
>  
>  
> -----------------------------------------------------------------------
> William J. Coirier, Ph.D.
> Director, Aerosciences and Engineering Analysis
> Advanced Technology Division
> Kratos/Digital Fusion, Inc.
> 4904 Research Drive
> Huntsville, AL 35805
> 256-327-8170
> 256-327-8120 (fax)
>  
> 
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> 
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