On Fri, Apr 27, 2012 at 3:57 PM, Peter Brune <[email protected]> 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