of course, in that situation Vertex/Weight are just useless marker :P -Simo
http://people.apache.org/~simonetripodi/ http://simonetripodi.livejournal.com/ http://twitter.com/simonetripodi http://www.99soft.org/ On Fri, Mar 2, 2012 at 10:14 PM, Simone Tripodi <simonetrip...@apache.org> wrote: > Hi James, > > looking at the the code I think we can safety keep the Weighted* > version AND use external functions you described. It is the same > Comparable/Comparator pattern, WDYT? > > 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 10:09 PM, James Carman > <jcar...@carmanconsulting.com> wrote: >> My point isn't that we would not need weights ever but we're putting a >> needless restriction on the users (implementing a marker interface). The >> Edge and Vertex interfaces add no value. >> >> The weights can be external, too. It's only a function from edge to >> weight. Your algorithm can take a function for its weights. The files >> library does it similar to this. >> On Mar 2, 2012 3:08 PM, "Ted Dunning" <ted.dunn...@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 < >>> squar...@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/ >>> > >>> > >>> > ------------------------------**------------------------------**--------- >>> > To unsubscribe, e-mail: dev-unsubscribe@commons.**apache.org< >>> dev-unsubscr...@commons.apache.org> >>> > For additional commands, e-mail: dev-h...@commons.apache.org >>> > >>> > >>> --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
