Re: [Axiom-developer] touchgraph, hypertex, hypergraph

[Pierre Doucy]

Hi all,

I'm not sure I fully understand what you what to do w/ graphs and if
you really need the "click somewhere to move the graph", but here we
go

> There is another project called HyperGraph that is quite similar
> to TouchGraph but uses a hyperbolic layout. See
>
> [...] 

Graphviz ( http://www.graphviz.org/ ) might help too. I won't give you
a java applet, but just any graphic file format (PDF, PS, JPG, ...),
and is available both from a standalone command-line program, or
through a programmatic interface.

> 
> But when I gave it the full 1300 node graph, what it drew was
> a graph so dense that all the edges overlapped into something
> that looked just like a big ball of wool and the program took
> a very long time to redraw the graph if you even touched it
> anywhere [...]

Depending on the complexity of your graph, graphviz is able to draw
huge graphs without too much pain, and the layout is generally very
readable.

>
>
> Clearly in order to draw the Axiom algebra graph, we are going
> to have to do it in some hierarchical manner but hopefuly one
> that can be computed from the structure of the graph - not
> imposed manually like the current layers in the Axiom makefiles.
> Some day real soon now I hope to find a source for some cookbook
> graph theory programs what can manipulate graphs of this size,
> find strongly connected component, prune redundant edges, etc.

There's a (C++) library - boost (www.boost.org,
http://www.boost.org/libs/graph/doc/table_of_contents.html), which is
a generic programming library, allowing you to represent a graph in
any manner (adjacency lists, adjacency matrix,...) , and provides some
basic algorithms.
The paradigm behind boost - generic programming - is somewhat weird,
but it actually allows great flexibility. I used it in a project
related to random graphs/social networks. If I remember well, someone
I used to work with (and who reads this list) implemented the
algorithm to find strongly connected components.
Besides, it integrates with graphviz, in the sense that you can import
and export from the graphviz format to boost (see
http://www.boost.org/libs/graph/doc/write-graphviz.html,
http://www.boost.org/libs/graph/doc/read-graphviz.html )

Hope that helps...


Pierre


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Cats are intended to teach us that not everything in nature has a function.