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AStar Visitor Concept

3rdParty/boost/1.78.0/libs/graph/doc/AStarVisitor.html

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AStar Visitor Concept

This concept defines the visitor interface for astar_search(). Users can define a class with the AStar Visitor interface and pass an object of the class to astar_search(), 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 AStar Visitor. | | vis | An object of type V. | | G | A type that is a model of Graph. | | g | An object of type const G&. | | e | An object of type boost::graph_traits<G>::edge_descriptor. | | s,u,v | An object of type boost::graph_traits<G>::vertex_descriptor. | | d | An object of type DistanceMap. | | WeightMap | A type that is a model of Readable Property Map. | | w | An object of type WeightMap. |

Associated Types

none

Valid Expressions

NameExpressionReturn TypeDescription
Initialize Vertexvis.initialize_vertex(u, g)voidThis is invoked on each vertex of the graph when it is first initialized (i.e., when its property maps are initialized).
Discover Vertexvis.discover_vertex(u, g)voidThis is invoked when a vertex is first discovered and is added to the OPEN list.
Examine Vertexvis.examine_vertex(u, g)voidThis is invoked on a vertex as it is popped from the queue (i.e., it has the lowest cost on the OPEN list). This happens immediately before examine_edge() is invoked on each of the out-edges of vertex u.
Examine Edgevis.examine_edge(e, g)voidThis is invoked on every out-edge of each vertex after it is examined.
Edge Relaxedvis.edge_relaxed(e, g)voidUpon examination, if the following condition holds then the edge is relaxed (the distance of its target vertex is reduced) and this method is invoked:
tie(u, s) = incident(e, g);
D d_u = get(d, u), d_v = get(d, s);
W w_e = get(w, e);
assert(compare(combine(d_u, w_e), d_s));

| | Edge Not Relaxed | vis.edge_not_relaxed(e, g) | void | Upon examination, if an edge is not relaxed (see above) then this method is invoked. | | Black Target | vis.black_target(e, g) | void | This is invoked when a vertex that is on the CLOSED list is ``rediscovered'' via a more efficient path and is re-added to the OPEN list. | | Finish Vertex | vis.finish_vertex(u, g) | void | This is invoked on a vertex when it is added to the CLOSED list. This happens after all of its out-edges have been examined. |

Models

See also

Visitor concepts


| Copyright © 2004 | Kristopher Beevers, Rensselaer Polytechnic Institute ([email protected]) |