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 > > > > >
