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From Simone Tripodi <simonetrip...@apache.org>
Subject Re: [graph] Why the Vertex and Edge interfaces?
Date Fri, 02 Mar 2012 20:35:24 GMT
That would be appreciated as well, thanks!
-Simo

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



On Fri, Mar 2, 2012 at 9:30 PM, Ted Dunning <ted.dunning@gmail.com> wrote:
> 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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>>
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