model.agent.humanAgent.aatom.tacticalLevel.navigation.pathfinder

Class AStarPathFinder

java.lang.Object

model.agent.humanAgent.aatom.tacticalLevel.navigation.pathfinder.PathFinder

model.agent.humanAgent.aatom.tacticalLevel.navigation.pathfinder.AStarPathFinder

public class AStarPathFinder
extends PathFinder

The A* Path Finder uses the A* algorithm to find a path from a start Position to a goal Position. Returns a path with only the goal position if no path could be found.

Author:

S.A.M. Janssen

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.ArrayList<AStarNode>	closed The set of nodes that have been searched through
private AStarNode[][]	graph The graph in array format.
private java.util.ArrayList<AStarNode>	open The set of nodes that we do not yet consider fully searched

Fields inherited from class model.agent.humanAgent.aatom.tacticalLevel.navigation.pathfinder.PathFinder

discretizedMap, map, precision

Constructor Summary

Constructors

Constructor and Description
AStarPathFinder(Map map, double precision) Creates an A* path finder.

Method Summary

Modifier and Type	Method and Description
private double	getHeuristicDistance(AStarNode node, AStarNode goal) Gets the heuristic distance between two AStarNodes.
private java.util.Collection<AStarNode>	getNeighbors(AStarNode node) Gets the neighbors of a AStarNode.
private AStarNode	getNodeFromPosition(Position position) Gets a AStar node from a Position.
java.util.List<Position>	getPath(Position start, Position goal, boolean smooth) Gets a feasible path from a specified start Position to a goal Position.
private Position	getPositionFromNode(AStarNode node) Gets a Position from a A Star Node.

Methods inherited from class model.agent.humanAgent.aatom.tacticalLevel.navigation.pathfinder.PathFinder

directPathPossible, getCornerPoints2, getPath, smooth

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

closed

private java.util.ArrayList<AStarNode> closed

The set of nodes that have been searched through

graph

private AStarNode[][] graph

The graph in array format.

open

private java.util.ArrayList<AStarNode> open

The set of nodes that we do not yet consider fully searched

Constructor Detail

AStarPathFinder

public AStarPathFinder(Map map,
                       double precision)

Creates an A* path finder.

Parameters:

map - The map.

precision - The precision.

Method Detail

getHeuristicDistance

private double getHeuristicDistance(AStarNode node,
                                    AStarNode goal)

Gets the heuristic distance between two AStarNodes. It is the euclidean distance between the two nodes (while assuming no obstacles), but corrects for the maximum angle allowed in the graph.

Parameters:

node - The starting node.

goal - The goal node.

Returns:

The heuristic distance between the nodes.

getNeighbors

private java.util.Collection<AStarNode> getNeighbors(AStarNode node)

Gets the neighbors of a AStarNode.

Parameters:

node - The node.

Returns:

The neighbors.

getNodeFromPosition

private AStarNode getNodeFromPosition(Position position)

Gets a AStar node from a Position.

Parameters:

position - The position.

Returns:

The node.

getPath

public java.util.List<Position> getPath(Position start,
                                        Position goal,
                                        boolean smooth)

Description copied from class: PathFinder

Gets a feasible path from a specified start Position to a goal Position. The method returns a list of points that are the corner points of the specified path.

Specified by:

getPath in class PathFinder

Parameters:

start - The start position.

goal - The goal position.

smooth - Smooth or not.

Returns:

The path.

getPositionFromNode

private Position getPositionFromNode(AStarNode node)

Gets a Position from a A Star Node.

Parameters:

node - The node.

Returns:

The position.