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From Ted Dunning <ted.dunn...@gmail.com>
Subject Re: [graph] Why the Vertex and Edge interfaces?
Date Fri, 02 Mar 2012 20:07:40 GMT
Having weights on vertices is quite common.  Consider any probability
transition network.  The weight on each node is the probability of being in
that state and the weights on the edges are conditional probabilties.

Page rank is a related example of having weights on nodes.

On Fri, Mar 2, 2012 at 12:40 AM, Claudio Squarcella <
squarcel@dia.uniroma3.it> wrote:

> Hi all,
>
>  Claudio is aware also about algorithms where weights are associated to
>> Vertex - he's preparing his PhD research on graphes - maybe he can
>> show us a more long-vision roadmap and evaluate benefits on
>> simplifying the design.
>>
>
> yes there are algorithms with weights on vertices. Of course those with
> weighted edges (like the ones already implemented) are much more widespread
> and frequently used, but still we cannot forget about that. Also, although
> on a secondary level, labels on vertices/edges are kind of important in
> many situations (including testing, debugging) where I think it is good to
> keep them distinct from the standard "toString" method (you might want to
> represent only a subset of info in the label, etc).
>
> Matthew Pocock suggested an alternative approach back in the days of
> weight abstraction:
>
>  * the graph itself is extremely simple and naked: no weights/labels on
>   vertices/edges;
>  * all properties are stored in some external structure, which I
>   imagine composed of associative maps (Map<Edge, Weight>, etc etc).
>
> He motivated the idea with a "personal use case": often graphs are used
> and reused with the same structure but different weights (and/or labels,
> etc). Now if James' question becomes a second use case, maybe it's the
> right time to exhume that idea ;)
>
> Ciao,
> Claudio
>
> --
> Claudio Squarcella
> PhD student at Roma Tre University
> http://www.dia.uniroma3.it/~**squarcel<http://www.dia.uniroma3.it/~squarcel>
> http://squarcella.com/
>
>
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