Re: [Boost-Users] [BGL] Daisy chaining algorithms using vistor mechanism?

From: Jeremy Siek (jsiek_at_[hidden])
Date: 2002-10-02 08:26:36

Hi Chris,

On Wed, 2 Oct 2002, Chris Russell wrote:
[snip]
cdr> finish_vertex method in a dfs_visitor will not compile however. This
cdr> is because the graph is passed by const reference into the visitor
cdr> method and in_edges requires a non-const graph reference?

No, in_edges is declared const for the graph parameter, at least for
adjacency_list, and it should be for other graph types as well.

cdr> Generally, I would like to be able to daisy chain graph algorithms -
cdr> that is invoke a sub-algorithm from within a visitor method called by
cdr> a controlling algorithm. This would require that the sub-algorithm
cdr> not change the graph topology, trample on properties used by its
cdr> controller (e.g. coloring), or otherwise invalidate vertex
cdr> descriptors or iterators so some care would need to be taken in
cdr> designing the sub-algorithm. But it seems like a useful mechanism for
cdr> extension.

You can do that as long as you use a different color map, etc.

Regards,
Jeremy

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 Jeremy Siek                          http://php.indiana.edu/~jsiek/
 Ph.D. Student, Indiana Univ. B'ton   email: jsiek_at_[hidden]
 C++ Booster (http://www.boost.org)   office phone: [phone]
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