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Bellman Ford Visitor Concept

This concept defines the visitor interface for bellman_ford_shortest_paths(). Users can define a class with the Bellman Ford Visitor interface and pass and object of the class to bellman_ford_shortest_paths(), thereby augmenting the actions taken during the graph search.

Refinement of

Copy Constructible (copying a visitor should be a lightweight operation).

Notation

V A type that is a model of Bellman Ford Visitor.

vis

An object of type V.

G

A type that is a model of Graph.

g

An object of type G.

e

An object of type boost::graph_traits<G>::edge_descriptor.

s,u

An object of type boost::graph_traits<G>::vertex_descriptor.

Associated Types

none

Valid Expressions

Name Expression Return Type Description

Examine Edge

vis.examine_edge(e, g)

void

This is invoked on every edge in the graph num_vertices(g) times.

Edge Relaxed

vis.edge_relaxed(e, g)

void

Upon examination, if the following condition holds then the edge is relaxed (its distance is reduced), and this method is invoked.
` tie(u,v) = incident(e, g);`
D d_u = get(d, u), d_v = get(d, v);
W w_e = get(w, e);
assert(compare(combine(d_u, w_e), d_v));

Edge Not Relaxed

edge_not_relaxed(e, g)

void

Upon examination, if the edge is not relaxed (see above) then this method is invoked.

Edge Minimized

vis.edge_minimized(e, g)

void

After num_vertices(g) iterations through the edge set of the graph are completed, one last iteration is made to test whether each edge was minimized. If the edge is minimized then this function is invoked.

Edge Not Minimized

edge_not_minimized(e, g)

void

If the edge is not minimized, this function is invoked. This happens when there is a negative cycle in the graph.

Models

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