[petsc-dev] VI vs. SNESLineSearchPostCheck and projecting to bounds

[Matthew Knepley]

On Fri, Apr 27, 2012 at 3:57 PM, Peter Brune <prbrune at gmail.com> wrote:

> Seems to me we have at least two ways of enforcing physicality or other
> constraints on the solution; SNESLineSearchPostCheck and the VI machinery.
> I'm trying to solve PFLOTRAN examples that make extensive use of
> SNESLineSearchPostCheck and am having to put postchecks at strategic places
> in SNESNGMRES and other solvers that don't just use the line searches
> directly make sure the solution becomes physical.
>
> Jed, you've already complained about post-check checking the step after
> taking it being nonsensical, and I agree on this point as well.  Should we
> move towards an interface so that there's a general "SNESProjectToBounds"
> or whatever, with VI doing what it needs to do through this as well? This
> way we have the ability to solve the constrained problems with all the
> solvers.  We already have hooks for this kind of thing in the DM.
>

I am cool with that. Its at least good enough for projected gradient.

   Matt


> Thanks,
>
> - Peter
>
>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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