/// <summary>
/// Generate an initial population of individuals
/// </summary>
/// <param name="individuals">An empty list to populate with the individuals</param>
public void Populate(ArrayList individuals)
{
while (individuals.Count < populationSize)
{
RoadNetwork network = new RoadNetwork(map);
int startIndex = network.AddVertexUnique(map.Start);
int endIndex = network.AddVertexUnique(map.End);
Vertex start = network.GetVertex(startIndex);
Vertex end = network.GetVertex(endIndex);
int nPaths = random.Next(10);
for (int i = 0; i < nPaths; i++)
{
int midpointIndex = network.AddVertexUnique(random.Next(map.Width), random.Next(map.Height));
Vertex midpoint = network.GetVertex(midpointIndex);
StepMutator.StepPath(network, start, midpoint);
StepMutator.StepPath(network, midpoint, end);
}
int nCross = random.Next(10);
for (int i = 0; i < nCross; i++)
{
Vertex startPoint = network.GetVertex(random.Next(network.VertexCount));
Vertex endPoint = network.GetVertex(random.Next(network.VertexCount));
StepMutator.StepPath(network, startPoint, endPoint);
}
network.SetEnd(endIndex);
individuals.Add(network);
}
}
/// <summary>
/// Generate an initial population of individuals
/// </summary>
/// <param name="individuals">An empty list to populate with the individuals</param>
public void Populate(ArrayList individuals)
{
RoadNetwork original = new RoadNetwork(map);
int startIndex = original.AddVertexUnique(map.Start);
int endIndex = original.AddVertexUnique(map.End);
Vertex start = original.GetVertex(startIndex);
Vertex end = original.GetVertex(endIndex);
StepMutator.StepPath(original, start, end);
original.SetEnd(endIndex);
individuals.Add(original);
while (individuals.Count < populationSize)
{
individuals.Add(StepMutator.Mutate((RoadNetwork)individuals[random.Next(individuals.Count)]));
}
}
/// <summary>
/// Make a path between two vertices in a RoadNetwork out of a number of edges connecting adjacent points.
/// </summary>
/// <param name="network">The RoadNetwork to make the path in</param>
/// <param name="start">The start Vertex of the path</param>
/// <param name="end">The end Vertex of the path</param>
public static void StepPath(RoadNetwork network, Vertex start, Vertex end)
{
int dX = end.Coordinates.X - start.Coordinates.X;
int dY = end.Coordinates.Y - start.Coordinates.Y;
int xStep = 1;
if (dX < 0)
{
dX = -dX;
xStep = -1;
}
int yStep = 1;
if (dY < 0)
{
dY = -dY;
yStep = -1;
}
int x = start.Coordinates.X;
int y = start.Coordinates.Y;
Vertex startVertex = start;
while (dX > 1 || dY > 1)
{
if (dX > dY)
{
x += xStep;
dX--;
}
else if (dY > dX)
{
y += yStep;
dY--;
}
else
{
x += xStep;
dX--;
y += yStep;
dY--;
}
int index = network.AddVertexUnique(x, y);
Vertex endVertex = network.GetVertex(index);
network.AddEdge(startVertex, endVertex);
startVertex = endVertex;
}
network.AddEdge(startVertex, end);
}
/// <summary>
/// Randomly alter a RoadNetwork to Produce a slightly different RoadNetwork
/// </summary>
/// <param name="source">The RoadNetwork to mutate</param>
/// <returns>The mutated RoadNetwork</returns>
public static RoadNetwork Mutate(RoadNetwork source)
{
Map map = source.Map;
int mapWidth = map.Width;
int mapHeight = map.Height;
int maxXChange = 1 + mapWidth / 10;
int maxYChange = 1 + mapHeight / 10;
source.ClearCopies();
source.SetVisited(false);
source.SetBroken(true);
RoadNetwork destination = new RoadNetwork(map);
int endVertexIndex = -1;
LinkedList<Vertex> vertexStack = new LinkedList<Vertex>();
source.Start.Visited = true;
vertexStack.AddFirst(source.Start);
while (vertexStack.Count > 0)
{
Vertex vertex = vertexStack.First();
vertexStack.RemoveFirst();
List<Vertex> nextVertices = new List<Vertex>();
for (int i = 0; i < vertex.EdgeCount; i++)
{
Edge edge = vertex.GetEdge(i);
Vertex nextVertex = edge.End;
if (!nextVertex.Visited)
{
edge.Broken = false;
nextVertex.Visited = true;
nextVertices.Add(nextVertex);
}
}
//If this vertex is a leaf of the tree and not the end vertex it has a 25% chance of
//begin removed.
if (nextVertices.Count > 0 || vertex == source.End || random.Next(4) > 0)
{
Coordinates coordinates = vertex.Coordinates;
if (vertex != source.Start && vertex != source.End && random.Next(4) == 0)
{
coordinates = RandomAdjacentPoint(vertex.Coordinates);
}
int index = destination.AddVertexUnique(vertex.Coordinates);
vertex.Copy = destination.GetVertex(index);
if (vertex == source.End)
{
endVertexIndex = index;
}
}
//Shuffle Vertices
for (int n = nextVertices.Count - 1; n > 0; n--)
{
int m = random.Next(n + 1);
Vertex temp = nextVertices[m];
nextVertices[m] = nextVertices[n];
nextVertices[n] = temp;
}
//Push vertices onto stack in shiffled order.
foreach (Vertex nextVertex in nextVertices)
{
vertexStack.AddFirst(nextVertex);
}
}
for (int i = 0; i < source.EdgeCount; i++)
{
Edge edge = source.GetEdge(i);
if ((!edge.Broken || random.Next(4) > 0) && edge.Start.Copy != null && edge.End.Copy != null)
{
StepPath(destination, edge.Start.Copy, edge.End.Copy);
}
}
int newVertices = random.Next(20);
for (int i = 0; i < newVertices; i++)
{
Vertex startVertex = destination.GetVertex(random.Next(destination.VertexCount));
int index = destination.AddVertexUnique(RandomAdjacentPoint(startVertex.Coordinates));
Vertex endVertex = destination.GetVertex(index);
destination.AddEdge(startVertex, endVertex);
}
if (endVertexIndex == -1)
{
throw new Exception("End vertex not found.");
}
else
{
destination.SetEnd(endVertexIndex);
}
return destination;
}