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Do not use A* for Optimization, use Dijkstra, use all the nodes already in the queue (not visited) for optimization.

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glax 2024-07-29 04:21:22 +02:00
parent 62d527737a
commit 032cce4552
1 changed files with 69 additions and 27 deletions
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96
astar/Astar.cs
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@ -6,12 +6,10 @@ using OSM_Regions;
namespace astar
{
public class Astar(ValueTuple<float, float, float, float>? priorityWeights = null, ValueTuple<float, float, float, float>? optimizingWeights = null, int? explorationDistance = null, int? explorationMultiplier = null)
public class Astar(ValueTuple<float, float, float, float>? priorityWeights = null, int? explorationMultiplier = null)
{
private readonly ValueTuple<float, float, float, float> DefaultPriorityWeights = priorityWeights ?? new(0.75f, 1f, 0.1f, 0);
private readonly ValueTuple<float, float, float, float> OptimizingWeights = optimizingWeights ?? new(0, 0.07f, 0, 0);
private readonly int _explorationDistanceFromRoute = explorationDistance ?? 1200;
private readonly int _explorationMultiplier = explorationMultiplier ?? 65;
private readonly ValueTuple<float, float, float, float> DefaultPriorityWeights = priorityWeights ?? new(0.7f, 1.08f, 0, 0);
private readonly int _explorationMultiplier = explorationMultiplier ?? 200;
public Route FindPath(float startLat, float startLon, float endLat, float endLon, float regionSize, bool car = true, PathMeasure pathing = PathMeasure.Distance, string? importFolderPath = null, ILogger? logger = null)
{
@ -69,16 +67,14 @@ namespace astar
if(meetingEnds is null)
return new Route(graph, Array.Empty<Step>().ToList(), false);
List<Node> routeNodes = PathFound(graph, meetingEnds.Value.Item1, meetingEnds.Value.Item2, car).Steps.Select(s => s.Node1).ToList();
Dictionary<ulong, int> routeQueue = toVisitStart.UnorderedItems.Select(l => l.Element).Union(toVisitEnd.UnorderedItems.Select(l => l.Element)).Where(id =>
//List<Node> routeNodes = PathFound(graph, meetingEnds.Value.Item1, meetingEnds.Value.Item2, car).Steps.Select(s => s.Node1).ToList();
Queue<ulong> routeQueue = new();
foreach (ulong id in toVisitStart.UnorderedItems.Select(l => l.Element)
.Union(toVisitEnd.UnorderedItems.Select(l => l.Element)))
{
Node p = graph.Nodes[id];
return routeNodes.Any(route => route.DistanceTo(p) < _explorationDistanceFromRoute);
}).ToDictionary(id => id, _ => int.MinValue);
PriorityQueue<ulong, int> combinedQueue = new();
foreach ((ulong key, int value) in routeQueue)
combinedQueue.Enqueue(key, value);
ValueTuple<Node, Node>? newMeetingEnds = Optimize(graph, combinedQueue, car, rl, priorityHelper, pathing, startNode.Value, endNode.Value, logger);
routeQueue.Enqueue(id);
}
ValueTuple<Node, Node>? newMeetingEnds = Optimize(graph, routeQueue, car, rl, pathing, logger);
meetingEnds = newMeetingEnds ?? meetingEnds;
return PathFound(graph, meetingEnds!.Value.Item1, meetingEnds.Value.Item2, car, logger);
@ -102,18 +98,11 @@ namespace astar
OSM_Graph.Way way = graph.Ways[wayId.Key];
byte speed = SpeedHelper.GetSpeed(way, car);
if(speed < 1)
continue;
if(!way.AccessPermitted())
if(!IsNeighborReachable(speed, wayId.Value, fromStart, way, car))
continue;
if (car && !way.IsPriorityRoad())
speed = (byte)(speed * 0.75f);
if(wayId.Value && way.GetDirection() == (fromStart ? WayDirection.Backwards : WayDirection.Forwards) && car)
continue;
if(!wayId.Value && way.GetDirection() == (fromStart ? WayDirection.Forwards : WayDirection.Backwards) && car)
continue;
Node neighborNode = graph.Nodes[neighborId];
if (neighborNode.PreviousIsFromStart is not null &&
@ -137,7 +126,20 @@ namespace astar
return null;
}
private ValueTuple<Node, Node>? Optimize(Graph graph, PriorityQueue<ulong, int> combinedQueue, bool car, RegionLoader rl, PriorityHelper priorityHelper, PathMeasure pathing, Node startNode, Node goalNode, ILogger? logger = null)
private static bool IsNeighborReachable(byte speed, bool wayDirection, bool fromStart, OSM_Graph.Way way, bool car)
{
if(speed < 1)
return false;
if(!way.AccessPermitted())
return false;
if(wayDirection && way.GetDirection() == (fromStart ? WayDirection.Backwards : WayDirection.Forwards) && car)
return false;
if(!wayDirection && way.GetDirection() == (fromStart ? WayDirection.Forwards : WayDirection.Backwards) && car)
return false;
return true;
}
private ValueTuple<Node, Node>? Optimize(Graph graph, Queue<ulong> combinedQueue, bool car, RegionLoader rl, PathMeasure pathing, ILogger? logger = null)
{
int currentPathLength = graph.Nodes.Values.Count(node => node.PreviousNodeId is not null);
int optimizeAfterFound = (int)(combinedQueue.Count * _explorationMultiplier); //Check another x% of unexplored Paths.
@ -145,11 +147,51 @@ namespace astar
ValueTuple<Node, Node>? newMeetingEnds = null;
while (optimizeAfterFound-- > 0 && combinedQueue.Count > 0)
{
ulong nodeId = combinedQueue.Peek();
Node node = graph.Nodes[nodeId];
bool fromStart = (bool)node.PreviousIsFromStart!;
newMeetingEnds = ExploreSide(fromStart, graph, combinedQueue, rl, priorityHelper, fromStart ? goalNode : startNode, car, OptimizingWeights, pathing, logger);
ulong currentNodeId = combinedQueue.Dequeue();
Node currentNode = graph.Nodes[currentNodeId];
bool fromStart = (bool)currentNode.PreviousIsFromStart!;
foreach ((ulong neighborId, KeyValuePair<ulong, bool> wayId) in currentNode.Neighbors)
{
if (!graph.ContainsNode(neighborId))
graph.ConcatGraph(Graph.FromGraph(rl.LoadRegionFromNodeId(neighborId)));
if (!graph.ContainsWay(wayId.Key))
{
logger?.LogDebug("Loading way... This will be slow.");
foreach (global::Graph.Graph? g in rl.LoadRegionsFromWayId(wayId.Key))
graph.ConcatGraph(Graph.FromGraph(g));
}
OSM_Graph.Way way = graph.Ways[wayId.Key];
byte speed = SpeedHelper.GetSpeed(way, car);
if(!IsNeighborReachable(speed, wayId.Value, fromStart, way, car))
continue;
if (car && !way.IsPriorityRoad())
speed = (byte)(speed * 0.75f);
Node neighborNode = graph.Nodes[neighborId];
if (neighborNode.PreviousIsFromStart is not null &&
neighborNode.PreviousIsFromStart != fromStart) //Check if we found the opposite End
{
newMeetingEnds = fromStart ? new(currentNode, neighborNode) : new(neighborNode, currentNode);
}
float metric = (currentNode.Metric ?? float.MaxValue) + (pathing is PathMeasure.Distance
? (float)currentNode.DistanceTo(neighborNode)
: (float)currentNode.DistanceTo(neighborNode) / speed);
if (neighborNode.PreviousNodeId is null || (neighborNode.PreviousIsFromStart == fromStart && neighborNode.Metric > metric))
{
neighborNode.PreviousNodeId = currentNodeId;
neighborNode.Metric = metric;
neighborNode.PreviousIsFromStart = fromStart;
combinedQueue.Enqueue(neighborId);
}
logger?.LogTrace($"Neighbor {neighborId} {neighborNode}");
logger?.LogDebug($"Optimization Contingent: {optimizeAfterFound}/{combinedQueue.Count}");
}
}
logger?.LogDebug($"Nodes in Queue after Optimization: {combinedQueue.Count}");
return newMeetingEnds;
}