[petsc-dev] PetscSection

[Jed Brown]

On Sat, Nov 10, 2012 at 2:05 PM, Matthew Knepley <knepley at gmail.com> wrote:

> Well, you have to designate the set with something. The easiest thing to
> use is
> an integer, so I use that. This is the only value associated with the set,
> so I
> would say Labels really only make sets.
>

I was looking at DMComplexGetLabelValue() and didn't realize it's just one
value per stratum. So you get the value associated with a point by
searching to find which stratum it resides in. In the implementation, if
point is not in the set specified by the label, it does not set *value. Is
that intentional? And there is no way to query stratum values without
getting a point that is a member. What about if a given level happens to be
empty?

Also, linear search, oh my. ;-)


>
> Exactly, they are sorted by strata, not dimension.
>

Okay, then dimensional query would really need to return an IS, provided it
didn't switch to sorting by dimension.


Can you answer how you can distinguish a quad from a tet in a
non-interpolated mesh?
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