[petsc-dev] VecNestSetSubVec for VecNest.

[Jed Brown]

Yes, I made this transformation for MatNest in January. It will be easier
for VecNest.
On Oct 16, 2011 3:23 PM, "Vijay S. Mahadevan" <vijay.m at gmail.com> wrote:

> > Let's wait on optimizing until we have a use case where it matters. Since
> > everything else expects data structures to be rebuilt if anything
> changes, I
> > don't think it's a concern just yet. If we allow more resizing in the
> > future, we can optimize this routine.
>
> Agreed. No need for premature optimization.
>
> I do find the flow of creating a Nest vector odd now that the
> SetSubVec* are in place. Because due to the VecCreateNest signature,
> you still need to provide a set of vectors to create the leaf nodes.
> Perhaps it might be useful to modify this signature to conform to the
> usual strategy now ? i.e., VecCreate(), VecSetSizes(), VecSetType(),
> VecSetFromOptions(), VecSetSubVecs(), VecAssemblyBegin/End() ?
>
> On Sun, Oct 16, 2011 at 11:25 AM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
> > On Sat, Oct 15, 2011 at 10:12, Vijay S. Mahadevan <vijay.m at gmail.com>
> wrote:
> >>
> >> Find attached the bundle with the changes for
> >> VecNestSetSubVec/VecNestSetSubVecs. The test file and the outputs are
> >> also included in the bundle. Feel free to modify the documentation if
> >> need be.
> >
> > Thanks, applied.
> >
> >>
> >> The only thing that I think needs a better implementation is the
> >> SetSubVecs where I've just looped over the indices and recursively
> >> called the single SetSubVec. This was hard to optimize since
> >> accommodating variable vectors involves traversing the IS one by one
> >> and I couldn't figure out a way to implement this concurrently.
> >> Anyway, if you can think of something better, let me know.
> >
> > Let's wait on optimizing until we have a use case where it matters. Since
> > everything else expects data structures to be rebuilt if anything
> changes, I
> > don't think it's a concern just yet. If we allow more resizing in the
> > future, we can optimize this routine.
>
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