On Sun, May 15, 2011 at 05:33, Dmitry Karpeev <karpeev at mcs.anl.gov> wrote:
> Would it be dangerous to be adding fields to a PetscLayout shared by > many Vecs/Mats (hence, PCs)? > I think PetscLayout should be strictly immutable after PetscLayoutSetUp(). Yes, in fact, a field, at least in my mind, is more than just > combinatorial information (IS), and might > involve some linear-algebraic information (e.g., if getting the > corresponding subvec or updating > the containing vec requires a linear transformation). > I think this might be snowballing beyond what is reasonable to handle at this level. Someone might say that converting [Density,Momentum,Energy] to [Pressure,Velocity,Temperature] has some semantic meaning to them and they want to tell PETSc about it, but it may be a hard sell to demonstrate that an equation of state belongs in PetscLayout. This example isn't even contrived though: the relevant Schur complement for preconditioning low-Mach Euler is a parabolic operator in the pressure space, despite the fact that pressure is not a conserved variable (thus not explicitly present in the original system). -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20110515/615d6cc5/attachment.html>
