AStarVisitor

class graph_tool.search.AStarVisitor

Bases: object

A visitor object that is invoked at the event-points inside the astar_search() algorithm. By default, it performs no action, and should be used as a base class in order to be useful.

Methods

black_target(e)	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.
discover_vertex(u)	This is invoked when a vertex is first discovered and is added to the OPEN list.
edge_not_relaxed(e)	Upon examination, if the edge is not relaxed (see edge_relaxed()) then this method is invoked.
edge_relaxed(e)	Upon examination, if the following condition holds then the edge is relaxed (its distance is reduced), and this method is invoked.
examine_edge(e)	This is invoked on every out-edge of each vertex after it is examined.
examine_vertex(u)	This is invoked on a vertex as it is popped from the queue (i.e. it has the lowest cost on the OPEN list).
finish_vertex(u)	This is invoked on a vertex when it is added to the CLOSED list, which happens after all of its out edges have been examined.
initialize_vertex(u)	This is invoked on every vertex of the graph before the start of the graph search.

black_target(e)

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.

discover_vertex(u)

This is invoked when a vertex is first discovered and is added to the OPEN list.

edge_not_relaxed(e)

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

edge_relaxed(e)

Upon examination, if the following condition holds then the edge is relaxed (its distance is reduced), and this method is invoked.

(u, v) = tuple(e)
assert compare(combine(d[u], weight[e]), d[v])

examine_edge(e)

This is invoked on every out-edge of each vertex after it is examined.

examine_vertex(u)

This 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.

finish_vertex(u)

This is invoked on a vertex when it is added to the CLOSED list, which happens after all of its out edges have been examined.

initialize_vertex(u)

This is invoked on every vertex of the graph before the start of the graph search.