[BGL] BFS and copy problem (was Re: [boost] Compilation)

From: lucatoldo (luca.toldo_at_[hidden])
Date: 2002-01-24 05:06:48

I think there is something I do not know, rather important, about the 
process of adding edges to the graph object. Infact, even in the 
simple example/bfs.cpp if I swap the start with the ends, I get 
different results. Namely:

If I change the code from this

boost::add_edge(0,2,G);
boost::add_edge(1,1,G);
boost::add_edge(3,1,G);
...
boost::add_edge(4,1,G);

to 

boost::add_edge(2,0,G);
boost::add_edge(1,1,G);
boost::add_edge(1,3,G);
...
boost::add_edge(1,4,G);

then I get

the graph OK but the distances and the parent vectors are screwed:

I get

distances: 0 2 2 2 1
instead of
distances: 0 2 1 2 2

and

parent[0] = 0
parent[1] = 4
parent[2] = 4
parent[3] = 4
parent[4] = 0

instead of

parent[0] = 0
parent[1] = 2
parent[2] = 0
parent[3] = 2
parent[4] = 2

I feel I am missing some basic knowledge on how to appropriately use 
this powerful and amazingly fast system. I would love to learn the 
missing bit.

Looking forward your advice and sorry again for the dumminess of this 
question.