ufl team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Mon, Jan 25, 2010 at 03:09:06PM +0000, Garth N. Wells wrote:
>
>
> Anders Logg wrote:
> > On Mon, Jan 25, 2010 at 03:19:36PM +0100, Marie Rognes wrote:
> >> noreply@xxxxxxxxxxxxx wrote:
> >>> ------------------------------------------------------------
> >>> revno: 892
> >>> committer: Anders Logg <logg@xxxxxxxxx>
> >>> branch nick: ufl-main
> >>> timestamp: Mon 2010-01-25 13:26:37 +0100
> >>> message:
> >>>  Add function sort_elements for sorting elements backwards with nested sub
> >>>  elements first. Using pygraph library for sorting directed acyclic graph.
> >>> modified:
> >>>  ufl/algorithms/__init__.py
> >>>  ufl/algorithms/analysis.py
> >>>
> >>>
> >> Is pygraph super-standard?
> >
> > I don't know but it's in Ubuntu... :-)
> >
> > It was the simplest way I could find to store a list of elements based
> > on their dependencies to sub elements.
> >
> > If it's a problem, we could implement the sorting ourselves.
> >
>
> If it's simple, I would suggest implementing it ourselves to avoid a
> dependency since UFL didn't have any dependencies beyond the standard
> Python modules. It can wait until until the UFL/FFC change are complete
> though.

You mean like tomorrow?

If anyone has a simple piece of code to do the following, let me know:

  # Create directed graph
  g = digraph()

  # Add nodes (elements)
  for element in elements:
      g.add_node(element)

  # Add edges (dependencies)
  for element in elements:
      for sub_element in element.sub_elements():
          g.add_edge(element, sub_element)

  # Sort graph
  sorted_elements = topological_sorting(g)

--
Anders

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