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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 20:30:00 GMT
No way that I have time to make real contributions, but if I see a quick
something to drop into the discussion, I will.

On Fri, Mar 2, 2012 at 12:25 PM, Simone Tripodi <simonetripodi@apache.org>wrote:

> Hi Ted,
>
> thanks for your valuable feedback! Please take in consideration that
> contributions are more than welcome, so if you intend sending
> contributions about this algorithms, they would bu much more than
> appreciated!
>
> best,
> -Simo
>
> http://people.apache.org/~simonetripodi/
> http://simonetripodi.livejournal.com/
> http://twitter.com/simonetripodi
> http://www.99soft.org/
>
>
>
> On Fri, Mar 2, 2012 at 9:07 PM, Ted Dunning <ted.dunning@gmail.com> wrote:
> > 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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