On Mon, Feb 6, 2012 at 12:47 PM, Jed Brown <[email protected]> wrote:

On Mon, Feb 6, 2012 at 21:42, Matthew Knepley <[email protected]> wrote:

...

I don't like this because it would mean calling VecSetUp() all over the place. Couldn't the ghosting flag be on the same level as the sizes?

Maybe VecSetUp() is wrong because that would imply collective. This memory allocation is simple and need not be collective.

Ghosting information is an array, so placing it in VecSetSizes() would seem unnatural to me. I wouldn't really want VecSetGhosts(Vec,PetscInt,const PetscInt*) to be order-dependent with respect to VecSetType(), but maybe the VecSetUp() would be too messy.

I needed to be more specific. I think VecSetSizes(local, global, ghost) would work. Then VecSetGhostIndices() can be called anytime, and even remapped. Matt -- 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