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From Simone Tripodi <simonetrip...@apache.org>
Subject Re: [Graph] Weighted as an interface
Date Mon, 05 Dec 2011 09:01:14 GMT
Hi Claudio,
what a pleasant surprise! :) I was hoping commons-graph would have
caught the interest of researchers on that field, I'm really happy you
would like to contribute!

I agree with your observations, please fill new issues on JIRA[1] and
feel free to provide patches, I'll process them ASAP :)

Moreover, I start having the feeling the {{WeightedGraph}} is a
useless interface: it is enough marking the vertices/edges as weighted
depending on the problem... or not? At the end of the day,
{{WeightedGraph}} does nothing than having the the edges marked as
weighted, so Dijkstra signature changed as:

<V extends Vertex, WE extends WeightedEdge, G extends DirectedGraph<V,
WE>> WeightedPath<V, WE> findShortestPath( G graph,  V source, V
target )

still define well the input type, a graph wich relations are directed
edges and edges are weighted... WDYT?

Looking forward for your contributions, can't wait for them! :)
Simo

[1] https://issues.apache.org/jira/browse/SANDBOX

http://people.apache.org/~simonetripodi/
http://simonetripodi.livejournal.com/
http://twitter.com/simonetripodi
http://www.99soft.org/



On Mon, Dec 5, 2011 at 2:00 AM, James Carman <james@carmanconsulting.com> wrote:
> Welcome!  Contributions (and the contributor) are always welcome.  In my
> past life, I did quite a bit of graph programming to solve "business"
> problems.  We used yfiles, though.  I hope to get around to playing with
> [graph] someday too.  Please do submit a patch!
> On Dec 4, 2011 6:43 PM, "Claudio Squarcella" <squarcel@dia.uniroma3.it>
> wrote:
>
>> Hello,
>>
>> I have been reading the source in the past days and I found that the
>> concept of "weight" (e.g. weighted edge, graph, etc) could benefit from a
>> bit of abstraction.
>>
>> The basic idea would be to have an interface called Weighted with an
>> obvious method getWeight(). Changes in the code would easily derive from
>> that. As a side effect it would be easy to implement new stuff like
>> weighted vertices: not as glorious as weighted edges, but still needed in
>> some problems (e.g. all-pairs bottleneck paths) and therefore desirable for
>> a general purpose graph API.
>>
>> One step further. A weight is not necessarily a double: in some cases not
>> even a number, but rather a "comparable" of some sort. So I would suggest
>> to make use of generics in some way, possibly the smartest. Suggestions are
>> welcome :-)
>>
>> If my thoughts meet some interest I will work on a patch.
>>
>> Ciao,
>> Claudio
>>
>>
>> P.S.
>> I am a first-timer here, so what follows is a short introduction.
>> I am doing a PhD in Graph Drawing and Information Visualization. I always
>> looked for a standard, unified way to represent and handle graphs when
>> developing prototypes. So my interest in this project is quite natural, and
>> I am willing to help and see it become a robust project.
>>
>> --
>> Claudio Squarcella
>> PhD student at Roma Tre University
>> E-mail address: squarcel@dia.uniroma3.it
>> Phone: +39-06-57333215
>> Fax: +39-06-57333612
>> http://www.dia.uniroma3.it/~**squarcel<http://www.dia.uniroma3.it/~squarcel>
>>
>>
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>>

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