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
