/// <summary>
/// Copy an existing NodeGene. Only the id and the type will be copied.
/// </summary>
/// <param name="nodeGene"></param>
public NodeGene(NodeGene nodeGene)
{
_id = nodeGene.ID;
_type = nodeGene.Type;
_typeOfFunction = nodeGene.TypeOfActivationFunction;
_xValue = nodeGene.XValue;
_inputs = new List <ConnectionGene>();
}
/// <summary>
/// Create a new node gene with an id and a type
/// </summary>
/// <param name="id">of the node gene. Must be unique</param>
/// <param name="type">of the node gene</param>
public NodeGene(int id, NodeGeneType type, float xValue)
{
_id = id;
_type = type;
_xValue = xValue;
_inputs = new List <ConnectionGene>();
_typeOfFunction = ActivationFunctionHelper.Function.SIGMOID;
}
/// <summary>
/// Create a new node gene with an id and a type
/// </summary>
/// <param name="id">of the node gene. Must be unique</param>
/// <param name="type">of the node gene</param>
/// <param name="function">the type of activation function</param>
public NodeGene(int id, NodeGeneType type, float yValue, ActivationFunctionHelper.Function function)
{
_id = id;
_type = type;
_typeOfFunction = function;
_xValue = yValue;
_inputs = new List <ConnectionGene>();
}
/// <summary>
/// Mutate the genome and replaces an existing connection with a new node and two new connections.
/// The existing connection will be disabled and a new node will be created. The new node will
/// be set between the input and output node of the old connection.
/// Two connections will be created. The first one is from the disabled connections input node to the newly created node with a weight of 1.
/// The second is from the newly created input node the the disabled connections output node with the weight if the disabled connection.
/// If the connection is already disabled, null will be returned
/// </summary>
/// <param name="connection">the existing connection that will be replaced</param>
/// <returns>an array with 4 objects.
/// Index 0: the disabled connection
/// Index 1: the newly created Node
/// Index 2: the newly created Connection between the Input and the newly created node and a weight of 1
/// Index 3: the newly created Connection between the newly created node and the output node with the weight of the given connection.
/// Return null, if the connection is already disabled</returns>
public System.Object[] AddNodeMutation(ConnectionGene connection, int nodeID, int inToNewNodeInnovationNumber, int newToOutNodeInnovationNumber)
{
//Test if the connection is available
if (!IsNodePossible(connection))
{
return(null);
}
NodeGene inNode = _nodes[connection.InNode];
NodeGene outNode = _nodes[connection.OutNode];
//Disable the connection
connection.Expressed = false;
//TODO new
float yValue = inNode.XValue + ((outNode.XValue - inNode.XValue) / 2);
//Get the activation function
ActivationFunctionHelper.Function type = Random.Range(-1f, 1f) >= 0 ? inNode.TypeOfActivationFunction : outNode.TypeOfActivationFunction;
NodeGene newNode = new NodeGene(nodeID, NodeGeneType.HIDDEN, yValue, type);
ConnectionGene inToNewNodeConnection = new ConnectionGene(inNode.ID, newNode.ID, 1f, true, inToNewNodeInnovationNumber);
ConnectionGene newToOutNodeConnection = new ConnectionGene(newNode.ID, outNode.ID, connection.Weight, true, newToOutNodeInnovationNumber);
_nodes.Add(newNode.ID, newNode);
_connections.Add(inToNewNodeConnection.InnovationNumber, inToNewNodeConnection);
_connections.Add(newToOutNodeConnection.InnovationNumber, newToOutNodeConnection);
System.Object[] changedValues = new System.Object[4];
changedValues[0] = connection;
changedValues[1] = newNode;
changedValues[2] = inToNewNodeConnection;
changedValues[3] = newToOutNodeConnection;
return(changedValues);
}
