--snip-- (sorry, first reply was too big)
Hi Nick,
Thanks for the explanation of the distributed BFS. This is indeed quite helpful. Especially at later stages. I haven't gotten to a point to comment on the data model but the current architecture is swell from what I can judge.
I hesitate to ask explanation at every minor detail but I now confused about passing the same vertex descriptor. Specifically I didn't quite grasp the statement "source vertex just has to be graph_traits<Graph>::vertex_descriptor, which you can construct using vertex() call if you want to generate it from a global vertex index". The source vertex has to graph_traits<Graph>::vertex_descriptor which I takes two arguments the index and the graph --these two parameters can only identify local vertices. For global vertices we need global descriptors which also require the owner.
Appreciate your help in clarifying this.
Thanks Sandeep
The vertex() call takes a global index and constructs a vertex_descriptor, which is basically a pair containing the local index and the owning process. vertex(i, g) will construct the i'th vertex descriptor in g on any process, regardless of where the vertex is actually stored. The confusion is that there are two indices here, global indices, and local indices. The graph distribution object maps between the two. vertex() takes a global index, specifically for this use case. Hope that helps, Nick