On Tue, Nov 19, 2013 at 4:35 PM, Geoffrey Irving <[email protected]> wrote:
> The documentation for DMPlexGetStratumIS helpfully explains that the
> "value" argument is
>
> - value - The stratum value
>
This is exactly right. A DMLabel is a map from value --> {set of integers}.
There
are no builtin semantics on the values.
> One has to look in DMPlexStratify to find that the value is probably
> (the word "value" isn't actually used) either the dimension or the
> codimension. But not which!
>
DMPlexStratify() builds a DMLabel called "depth". The values in this label
are point depths in the mesh graph.
> The documentation for DMPlexStratify seems to imply that the meaning
> of the stratum value is up to the user. Is that right? If so it
> makes it hard to design robust libraries; the library would have to
> either know how the DMPlex was created or reverse engineer the
> dimension 0 stratum from the coordinate section (or similar
> hideousness).
>
> If there is a convention, can I add it to the documentation of
> DMPlexGetStratumIS and DMPlexGetStratumSize?
These are documenting the generic DMLabel interface. These functions are
in fact just the delegator pattern, where they dispatch to the named label.
I
am considering just eliminating all of them in favor of DMGetLabel().
Matt
>
> Geoffrey
>
--
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
