[erlang-questions] digraph questions

[Hugo Mills]

On Tue, Apr 09, 2019 at 12:46:21PM +1200, Richard O'Keefe wrote:
> The obvious way to visualise a graph would be to drive
> something like GraphViz or Gephi or, ideally, UbiGraph
> (https://github.com/alan86alves/ubigraph_server has a
> copy of the Linux x86-64 version; the official source
> is currently unreachable).  There is an erlubi. But
> perhaps the thing you might want to look at first is
> https://github.com/aol/erlgraph
> It will take a bit of patching to get up to date with
> current versions of Erlang and Cowboy.

   These kinds of graphs get *very* dense, and it's almost impossible
to draw the whole graph in any meaningful sense. You can't just throw
the graph at a graph drawing package and expect to get usable output.

   You really need to spend the time on working out what it is you
want to show, whether it's "everything directly relating to this one
character", or "the sequence of events in this scene", or "who was
with who over the course of the story", and then strip out everything
else to show the graph. You're going to be spending much more of your
time thinking about *what* to show than how to show it, in my
experience.

   Hugo.

> On Tue, 9 Apr 2019 at 11:29, <lloyd@REDACTED> wrote:
> 
> > The Erlang digraph library looks like it may provide an interesting way to
> > diagram scenes in a novel.
> >
> >
> >
> > 1> Scene10 = digraph:new().
> >
> >
> >
> > Imagine:
> >
> >
> >
> > Setting:"park"
> >
> > Character1:"Franco"
> >
> > Character2:"Sophia"
> >
> >
> >
> > 2> digraph:add_vertex(Scene10, "Park", "Night").
> >
> > 3> digraph:add_vertex(Scene10, "Franco", "Old and fat").
> >
> > 4> digraph:add_vertex(Scene10, "Sophia", "Young and beautiful").
> >
> > 5> digraph:add_edge(Scene10, "Franco", "Sophia", "loves").
> >
> >
> >
> > OK to here EXCEPT command 5 returns:
> >
> >
> >
> > ['$e'|0]
> >
> >
> >
> > 6> digraph:add_edge(Scene10, "Sophia", "Franco", "hates").
> >
> >
> >
> > OK to here EXCEPT command 5 returns:
> >
> >
> >
> > ['$e'|0]
> >
> >
> >
> > 6> digraph:add_edge(Scene10, "Sophia", "Franco", "hates").
> >
> > ['$e'|1]
> >
> >
> >
> > Wah!
> >
> >
> >
> > Question 1: How do I see labels?
> >
> >
> >
> > Question 2: Be cool to add a sequence of actions. I can probably figure
> > this out, but is there an elegant solution?
> >
> >
> >
> > Question 3: I'd love to visualize the graph. I see it can be done in
> > Elixir. But I don't know Elixir. Has anyone programmed a way to visualize
> > digraphs in Erlang?
> >
> >
> >
> > Comment: Digraph is crying out for a comprehensive tutorial. I'd love to
> > do it, but just don't know enough yet.
> >
> >
> >
> > Many thanks,
> >
> >
> >
> > LRP
> >
> >
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > erlang-questions mailing list
> > erlang-questions@REDACTED
> > http://erlang.org/mailman/listinfo/erlang-questions
> >

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-- 
Hugo Mills             | Books are superior to radio: the soundtrack is
hugo@REDACTED carfax.org.uk | better
http://carfax.org.uk/  |
PGP: E2AB1DE4          |
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