[pyton] how to use dijkstra's shortest path algorithm

Hi everyone,

I am completely new to Boost, and have been playing with it through the python bindings, but I'm getting a bit confused. 

What I'm trying to do is use dijkstra's shortest path algorithm (with predecessor) on a graph I'm reading in from a graphviz file. My code is as below:

import boost.graph as bgl

#Create a new graph from the graphviz file
graph = bgl.Graph.read_graphviz('code/mst.dot')
#try to get shortest path
min_paths = bgl.dijkstra_shortest_paths(graph,graph.vertices.next(),predecessorMap,distanceMap)

which is the way variables should be entered according to the documentation.

dijkstra_shortest_paths(graph, root_vertex, predecessor_map = None, 

                        distance_map = None, weight_map = None, 

                        visitor = None)

I'm not completely sure what I'm doing wrong. Basically, I would like to get the predecessors and then print them out to screen.

And finally, how do you actually access a single vertex. Say I want vertex one of my graph, or vertex two or whatever. Do I have to iterate over until I get there or is there an easier way?

Thanks (sorry is this has already been posted. I searched but couldn't find a previous posting)

Neeraj








	
	
		
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