Boost C++ Libraries

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distance_recorder<DistanceMap, EventTag>

This is an EventVisitor that records the distance of a vertex (using a property map) from some source vertex during a graph search. When applied to edge e = (u,v), the distance of v is recorded to be one more than the distance of u. The distance recorder is typically used with the on_tree_edge or on_relax_edge events and cannot be used with vertex events.

distance_recorder can be used with graph algorithms by wrapping it with the algorithm specific adaptor, such as bfs_visitor and dfs_visitor. Also, this event visitor can be combined with other event visitors using std::pair to form an EventVisitorList.

Example

See the example for bfs_visitor.

Model of

EventVisitor

Where Defined

boost/graph/visitors.hpp

Template Parameters

Parameter Description Default

DistanceMap A WritablePropertyMap where the key type and the value type are the vertex descriptor type of the graph.

EventTag The tag to specify when the distance_recorder should be applied during the graph algorithm. EventTag must be an edge event.

Parameter	Description	Default
`DistanceMap`	A WritablePropertyMap where the key type and the value type are the vertex descriptor type of the graph.
`EventTag`	The tag to specify when the `distance_recorder` should be applied during the graph algorithm. `EventTag` must be an edge event.

Associated Types

Type	Description
`distance_recorder::event_filter`	This will be the same type as the template parameter `EventTag`.

Member Functions

Member Description

distance_recorder(DistanceMap pa); Construct a distance recorder object with distance property map pa.

template <class Edge, class Graph> void operator()(Edge e, const Graph& g); Given edge e = (u,v), this records the distance of v as one plus the distance of u.

Member	Description
`distance_recorder(DistanceMap pa);`	Construct a distance recorder object with distance property map `pa`.
`template <class Edge, class Graph> void operator()(Edge e, const Graph& g);`	Given edge e = (u,v), this records the distance of v as one plus the distance of u.

Non-Member Functions

Function	Description
`template <class DistanceMap, class Tag> distance_recorder<DistanceMap, Tag> record_distances(DistanceMap pa, Tag);`	A convenient way to create a `distance_recorder`.