[petsc-dev] DMPlex "chart" term

[Matthew Knepley]

On Wed, Oct 11, 2017 at 4:54 AM, Patrick Sanan <patrick.sanan at gmail.com>
wrote:

> Another terminology question to help with the docs.
>
> What's the origin of the term "chart" in DMPlex? I'm only previously
> familiar with the term in the context of manifolds (where chart =
> homeomorphism from an open set in the manifold to an open set in R^n).
>

That is what it is supposed to be. A chart is coordinates on a patch of the
manifold. We intend the same thing here in that you can
locally refer to points with a given name, but they may have a different
name on another chart (process). The names are matched up using the PetscSF.


> In terms of the use in DMPlex, is there anything wrong with thinking of
> "chart" as a shorter way to say "interval of integers, closed on the left
> and open on the right, e.g.  [pStart,pEnd)"?
>

No, since we depend on continuity of point names almost everywhere.

  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

https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
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