OK, I think I've got it, thanks. I was using -- for a bidirectional connection. --Kip
Sent from my iPad On Feb 15, 2013, at 7:47 PM, Raul Miller <[email protected]> wrote: > On Fri, Feb 15, 2013 at 7:23 PM, km <[email protected]> wrote: >> My code is for directed graphs as defined in Graphs in Computer Science: >> >> http://web.cecs.pdx.edu/~sheard/course/Cs163/Doc/Graphs.html > > This is consistent with my intent when I used the phrase. > >> However, suppose our undirected graph is >> >> 0--1--2--3 (the only edges are those shown). >> >> Am I right that every set of two nodes is visitable from node 2? These are > > > I cannot say for sure, because you have not indicated the direction of > the connection. If the connections are all bi-directional, then yes. > But I would have diagramed that something like this: > > 0<-->1<-->2<-->3 > >> {0 1} contained in 0--1--2 >> >> {0 2} contained in 0--1--2 >> >> {0 3} contained in 0--1--2--3 >> >> {1 2} contained in 1--2 >> >> {1 3} contained in 1--2--3 >> >> {2 3} contained in 2--3 >> >> ( No order is implied in the conventional set notation {a b} ) > > I am not sure what you are getting at, here, But I will note that the > relevant visitable sets here (assuming 2-way connections) are: > > 1 node: > {2} > > 2 nodes: > {1 2} > {2 3} > > 3 nodes: > {0 1 2} > {1 2 3} > > 4 nodes: > {0 1 2 3} > > On the other hand if, for example, the connections only went from left > to right, the only visitable sets would be: > > 1 node: > {2} > > 2 nodes: > {2 3} > > That said, yes - ordering is irrelevant when discussing sets. It's > their construction - determining their contents - where ordering is > relevant. > >> Kip >> >> P.S. I do not expect my directed graph code to be efficient for large >> graphs and long chains, but I will experiment and report back. > > Thanks! > > -- > Raul > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
