Doug Gregor wrote:

On Feb 20, 2006, at 3:43 PM, Alejandro Aragón wrote:

...

Hi everyboty,

Can someone point to a concrete example of a graph without parallel edges??? I am using setS as my container for the edges but I still insert edges twice in my graph algorithm. Thank you,

When using setS for the OutEdgeListS, insertion of a parallel edge should have no effect at all. If this isn't the behavior you are seeing, we have a bug and we'll need to fix it.

Doug

Well, for some reason, the boolean inserted turns out to be always 1. I'll run an example and I will let you know. a^2

On Feb 28, 2006, at 1:23 AM, Alejandro Aragón wrote:

Well, it seems now that the problem is fixed. I was using a directedS graph with setS for the OutEdgeListS. I changed that to undirectedS and now edges are not added twice as before. I thought that setS completely discarded parallel edges no matter of the choice of the directivity of the graph. It doesn't make sense to me that you can have a directed graph with a disjoint set container that doesn't allow the parallel edge behavior. I think there should be some warning if you use setS with directedS right?

I think the Graph library is doing the right thing here. In a directed graph, the edges (u, v) and (v, u) are not parallel edges, so even with OutEdgeListS=setS you can have both in a graph. By using setS, you won't be able to have two edges (u, v) and (u, v). Doug