private void BuildGraph(StarSystem start, StarSystem goal, double maxJump)
{
logger.Trace("Building graph for route from '{0}' to '{1}'", start.Name, goal.Name);
List<StarSystem> systems = GetLocalSystems(start, goal).ToList();
logger.Trace("Building edges for route from '{0}' to '{1}'", start.Name, goal.Name);
for (int i = 0; i < systems.Count; i++)
{
StarSystem a = systems[i];
for (int j = 0; j < systems.Count; j++)
{
StarSystem b = systems[j];
if (a.Equals(b))
continue;
if (a.DistanceFrom(b) <= maxJump)
{
var edge = new Edge<StarSystem>(a, b);
double edgeWeight = CalculateEdgeWeight(a, b);
graph.AddVerticesAndEdge(edge);
weights.Add(edge, edgeWeight);
}
}
}
logger.Trace("{2} edges added for route from '{0}' to '{1}'", start.Name, goal.Name, graph.Edges.Count());
}
private IEnumerable<Edge<StarSystem>> FindPath(StarSystem start, StarSystem goal, double maxJump)
{
BuildGraph(start, goal, maxJump);
// if we only have one edge, then that is the shortest path
if (graph.Edges.Count() == 1)
return graph.Edges;
// setup the shortest path algorithm
var edgeCost = AlgorithmExtensions.GetIndexer(weights);
var tryGetPath = graph.ShortestPathsBellmanFord(edgeCost, start);
//var tryGetPath = graph.ShortestPathsDijkstra(edgeCost, start);
logger.Trace("Searching for route from '{0}' to '{1}'", start.Name, goal.Name);
IEnumerable<Edge<StarSystem>> path;
if (tryGetPath(goal, out path))
return path;
else
throw new RouteNotFoundException(string.Format("Unable to find route from '{0}' to '{1}'", start.Name, goal.Name));
}
public Route(StarSystem start, StarSystem end)
{
this.start = start;
this.end = end;
hops = new List<Edge<StarSystem>>();
}
public Route(IEnumerable<Edge<StarSystem>> path)
{
hops = path.ToList();
start = hops[0].Source;
end = hops[hops.Count - 1].Target;
}
public double DistanceFrom(StarSystem other)
{
return Location.DistanceFrom(other.Location);
}
/// <summary>
/// Gets a list of StarSystems that surround the starting system. The distance between the
/// starting system and the ending system defines the radius of the search circle.
/// </summary>
/// <param name="start">The starting point</param>
/// <param name="end">The goal system</param>
/// <returns>A list of systems inside the radius of the search circle</returns>
private IEnumerable<StarSystem> GetLocalSystems(StarSystem start, StarSystem end)
{
double radius = start.DistanceFrom(end);
return provider.Systems.Where(s => s.DistanceFrom(start) <= radius);
}
private double CalculateEdgeWeight(StarSystem a, StarSystem b)
{
return a.DistanceFrom(b);
}
public Route Find(StarSystem start, StarSystem end, double maxJump)
{
IEnumerable<Edge<StarSystem>> path = FindPath(start, end, maxJump);
return new Route(path);
}
public Route Find(StarSystem start, StarSystem end)
{
return Find(start, end, 15);
}
