Re: [Boost-users] BGL connected_components ComponentMap

From: Jens Müller (jens.mueller_at_[hidden])
Date: 2007-09-13 11:27:19

Andreas Fabri wrote:
> Hello,
> 
> Why does the ComponentMap not get accessed via the property map
> obtained with   get(vertex_index, g) ?

What exactly do you mean? The component map is not just used internally 
(after all, getting connected components is the whole purpose of the 
algorithm).

The color map, which is used internally only, is created using 
vertex_index if not explicitly passed.

> Many other algorithms do that, e.g. dijksta_shortest_paths.

Do exactly what?

Comparing
http://www.boost.org/libs/graph/doc/connected_components.html
and
http://www.boost.org/libs/graph/doc/dijkstra_shortest_paths.html
I don't see what you mean.

For Dijkstra, you don't have to pass the distance map and the color map, 
they are then created using the color map. Just the same as for 
connected_components().

> Is this just an inconsistency, or are there technical reasons.

I don't see the inconsistency.