public NewNodeMutation AddNode(Genome genome, List <NewNodeMutation> mutations)
{
List <Connection> candidateConnections = FindCandidateConnectionsForNewNode(genome);
Connection connectionToSplit = candidateConnections[Random.Next(candidateConnections.Count)];
connectionToSplit.Enabled = false;
// Check if this exact mutation has already been done this evolution cycle
int nodeId, toNewNodeId, fromNewNodeId;
List <NewNodeMutation> existingMutations = mutations.Where(x => x.SplittedConnectionId == connectionToSplit.Id).ToList();
if (existingMutations.Count > 0)
{
NewNodeMutation existingMutation = existingMutations[0];
nodeId = existingMutation.NewNodeId;
toNewNodeId = existingMutation.ToNewNodeConnectionId;
fromNewNodeId = existingMutation.FromNewNodeConnectionId;
}
else
{
nodeId = NodeId++;
toNewNodeId = ConnectionId++;
fromNewNodeId = ConnectionId++;
}
// Create new node
Node newNode = new Node(nodeId, NodeType.Hidden);
// Create new connections
Connection toNewNode = new Connection(toNewNodeId, connectionToSplit.FromNode, newNode);
connectionToSplit.FromNode.OutConnections.Add(toNewNode);
newNode.InConnections.Add(toNewNode);
toNewNode.Weight = 1;
Connection fromNewNode = new Connection(fromNewNodeId, newNode, connectionToSplit.ToNode);
newNode.OutConnections.Add(fromNewNode);
connectionToSplit.ToNode.InConnections.Add(fromNewNode);
fromNewNode.Weight = connectionToSplit.Weight;
genome.HiddenNodes.Add(newNode);
genome.Nodes.Add(nodeId, newNode);
genome.Connections.Add(toNewNodeId, toNewNode);
genome.Connections.Add(fromNewNodeId, fromNewNode);
genome.CalculateDepths();
return(new NewNodeMutation()
{
SplittedConnectionId = connectionToSplit.Id,
NewNodeId = newNode.Id,
ToNewNodeConnectionId = toNewNode.Id,
FromNewNodeConnectionId = fromNewNode.Id
});
}
public void MutateTopology(Genome g, MutationInformation info, List <NewNodeMutation> newNodeMutations, List <NewConnectionMutation> newConnectionMutations)
{
int possibleNewNodeMutations = FindCandidateConnectionsForNewNode(g).Count;
int possibleNewConnectionMutations = FindCandidateConnections(g).Count;
int allPossibleMutations = possibleNewNodeMutations + possibleNewConnectionMutations;
float addNewNodeChance = (float)possibleNewNodeMutations / (float)allPossibleMutations;
double rng = Random.NextDouble();
if (rng <= addNewNodeChance)
{
NewNodeMutation mutation = AddNode(g, newNodeMutations);
if (newNodeMutations.Where(x => x.SplittedConnectionId == mutation.SplittedConnectionId).Count() == 0)
{
newNodeMutations.Add(mutation);
}
if (info != null)
{
info.NumNewNodeMutations++;
}
}
else
{
NewConnectionMutation mutation = AddConnection(g, newConnectionMutations);
if (newConnectionMutations.Where(x =>
(x.FromNodeId == mutation.FromNodeId && x.ToNodeId == mutation.ToNodeId) ||
(x.FromNodeId == mutation.ToNodeId && x.ToNodeId == mutation.FromNodeId)
).Count() == 0)
{
newConnectionMutations.Add(mutation);
}
if (info != null)
{
info.NumNewConnectionsMutations++;
}
}
}
