On Wed, Dec 14, 2011 at 9:35 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
> On Wed, Dec 14, 2011 at 19:31, Barry Smith <bsmith at mcs.anl.gov> wrote: > >> If you are truly near 0 in temperature or pressure and differencing can >> push you over the limit then I submit it is perfectly reasonable to solve >> them as VI. >> > > Note that this tends to grow the algebraic systems quite a bit. Usually > such problems are solved in conservative variables (density, momentum, > energy), but the more troublesome constraints (pressure, temperature) are > nonlinear functions of the conservative variables. As currently > implemented, you would have to solve (density, momentum, energy, pressure, > temperature) in order to impose those constraints with SNESVI. I wonder if > there is a way to eliminate these constraints earlier so that the systems > don't grow so much. > The trouble is that the constraints can get "eliminated" only when they become active. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20111214/7848e0a6/attachment.html>