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Subject: Re: [Boost-users] dijkstra-example.cpp
From: Kunzman, Douglas (Doug) (DKunzman_at_[hidden])
Date: 2012-01-27 17:48:01

The tree that result from calling dijkstra's algorithm does not result in a each vertice have at least one black edge reaching it. I would assume something is wrong? Can someone offer some suggestions?


-----Original Message-----
From: boost-users-bounces_at_[hidden] [mailto:boost-users-bounces_at_[hidden]] On Behalf Of Jeremiah Willcock
Sent: Friday, January 27, 2012 4:18 PM
To: boost-users_at_[hidden]
Subject: Re: [Boost-users] dijkstra-example.cpp

On Fri, 27 Jan 2012, fergie wrote:

> I’ve been reviewing the dijkstra-example.cpp that is provided as part
> of boost Graph. I think I understand most of it and have been able to
> demonstrate the application working to my boss. I have one question
> about the code. When output the .dot file near the end of the program
> the results are shaded either grey or black. What is the significance
> of the black and grey lines?

Black lines are edges in the single-source shortest path tree, while gray lines are edges that are not in the tree. Look at for exactly what the tree represents.

> I’ve looked through the documentation and am also confused about the
> source and the target since we have an iterator going through the
> entire graph. What defines a source and target vertex?

The graph is directed, so each edge goes from a defined source to a defined target. The arrows in the output file show the directions of the edges.

-- Jeremiah Willcock

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