public TGPTerminal FindRandomTerminal(TGPTerminal current_terminal = null)
{
for (int attempts = 0; attempts < 10; attempts++)
{
double r = mWeightSum * TreeGP.Distribution.DistributionModel.GetUniform();
double current_sum = 0;
foreach (KeyValuePair <TGPTerminal, double> point in mTerminals)
{
current_sum += point.Value;
if (current_sum >= r)
{
if (point.Key != current_terminal)
{
return(point.Key);
}
else
{
break;
}
}
}
}
return(current_terminal);
}
public void AddTerminal(TGPTerminal terminal, double weight = 1)
{
mTerminals.Add(new KeyValuePair <TGPTerminal, double>(terminal, weight));
terminal.mTerminalIndex = mTerminals.Count - 1;
terminal.mIsConstant = true;
mWeightSum += weight;
}
public void AddTerminal(TGPTerminal terminal, double weight = 1)
{
mTerminals[terminal.Symbol] = new KeyValuePair <TGPTerminal, double>(terminal, weight);
terminal.mTerminalIndex = mTerminals.Count - 1;
terminal.mIsConstant = false;
mWeightSum += weight;
}
/// <summary>
/// Method that implements the "Point Mutation" described in Section 2.4 of "A Field Guide to Genetic Programming"
/// In Section 5.2.2 of "A Field Guide to Genetic Programming", this is also described as node replacement mutation
/// </summary>
public virtual void MicroMutate()
{
TGPNode node = FindRandomNode();
if (node.IsTerminal)
{
TGPTerminal terminal = FindRandomTerminal();
int trials = 0;
int max_trials = 50;
while (node.Primitive == terminal)
{
terminal = FindRandomTerminal();
trials++;
if (trials > max_trials)
{
break;
}
}
if (terminal != null)
{
node.Primitive = terminal;
}
}
else
{
int parameter_count = node.Arity;
TGPOperator op = mOperatorSet.FindRandomOperator(parameter_count, (TGPOperator)node.Primitive);
if (op != null)
{
node.Primitive = op;
}
}
}
public void AddConstant(string symbol, object value, double weight = 1)
{
TGPTerminal terminal = new TGPTerminal("");
terminal.Value = value;
AddTerminal(terminal);
terminal.mSymbol = symbol;
}
/// <summary>
/// Method that adds a function with no arguments to the constant set
/// </summary>
/// <param name="symbol">The symbol for the function</param>
/// <param name="function">The actual mechanism of the function which returns a value</param>
/// <param name="weight">weight for the function for selection</param>
public void AddFunction(string symbol, TGPTerminal.FunctorHandle function, double weight = 1)
{
TGPTerminal terminal = new TGPTerminal("");
terminal.FunctionHandle = function;
terminal.Value = null;
AddTerminal(terminal);
terminal.mSymbol = symbol;
}
public TGPTerminal Clone()
{
TGPTerminal clone = new TGPTerminal(mSymbol);
clone.mTerminalIndex = mTerminalIndex;
clone.mIsConstant = mIsConstant;
clone.mValue = mValue;
clone.FunctionHandle = FunctionHandle;
return(clone);
}
internal void Update(params object[] tags)
{
foreach (KeyValuePair <TGPTerminal, double> pair in mTerminals)
{
TGPTerminal terminal = pair.Key;
if (terminal.FunctionHandle != null)
{
terminal.Value = terminal.FunctionHandle(tags);
}
}
}
public bool IsVariable(TGPPrimitive primitive)
{
if (primitive.IsTerminal)
{
TGPTerminal terminal = primitive as TGPTerminal;
if (!terminal.IsConstant)
{
return(true);
}
}
return(false);
}