/// <summary>
/// The crossover function, takes two parent programs, and generates two sons
/// From the two parents.
/// </summary>
/// <param name="progParentOne">Parent program one</param>
/// <param name="progParentTwo">Parent program two</param>
/// <param name="progSonOne">Son program one</param>
/// <param name="progSonTwo">Son program two</param>
protected override void Crossover(BaseProgram baseProgParentOne, BaseProgram baseProgParentTwo,
out BaseProgram baseProgSonOne, out BaseProgram baseProgSonTwo)
{
TreeProgram progParentOne = (TreeProgram)baseProgParentOne;
TreeProgram progParentTwo = (TreeProgram)baseProgParentTwo;
TreeProgram progSonOne;
TreeProgram progSonTwo;
// Get the global random ...
ImprovedRandom rndRandom = GlobalRandom.m_rndRandom;
progSonOne = (TreeProgram)progParentOne.Clone();
progSonTwo = (TreeProgram)progParentTwo.Clone();
// Generate new sons more and more, until the new sons tree limit's are
// Good enough and stand the tree limits. Or just do this for the first time
// That sons are being generated.
for (int nRootNum = 0; nRootNum < progSonOne.m_arrRoots.Length; nRootNum++)
{
bool bGeneratedNewSons = false;
while (((progSonOne.m_arrRoots[nRootNum].Depth > this.m_nMaxOverallTreeDepth) ||
(progSonTwo.m_arrRoots[nRootNum].Depth > this.m_nMaxOverallTreeDepth)) ||
!bGeneratedNewSons)
{
// Clone both parent roots
progSonOne.m_arrRoots[nRootNum] = (Node)progParentOne.m_arrRoots[nRootNum].Clone();
progSonTwo.m_arrRoots[nRootNum] = (Node)progParentTwo.m_arrRoots[nRootNum].Clone();
// Random two nodes as a crossover points in the two sons (which are
// Now supposed to be a cloned version of the parents)
int nSelectNodeInParentOne = rndRandom.Next(
NodeHelper.CountNodes(progSonOne.m_arrRoots[nRootNum]));
int nSelectNodeInParentTwo = rndRandom.Next(
NodeHelper.CountNodes(progSonTwo.m_arrRoots[nRootNum]));
NodeHelper.NodeResult ndNodeToExchangeOne = NodeHelper.FindNode(
progSonOne.m_arrRoots[nRootNum], nSelectNodeInParentOne);
NodeHelper.NodeResult ndNodeToExchangeTwo = NodeHelper.FindNode(
progSonTwo.m_arrRoots[nRootNum], nSelectNodeInParentTwo);
// Exchange the crossover branches between the two sons, when it is done,
// The new sons are ready to be called "new sons" and not just a clone.
NodeHelper.ExchangeNodes(
ndNodeToExchangeOne.ndNode, ndNodeToExchangeOne.ndNodeParent,
ref progSonOne.m_arrRoots[nRootNum],
ndNodeToExchangeTwo.ndNode, ndNodeToExchangeTwo.ndNodeParent,
ref progSonTwo.m_arrRoots[nRootNum]);
bGeneratedNewSons = true;
}
}
baseProgSonOne = progSonOne;
baseProgSonTwo = progSonTwo;
}
public BaseProgram GetMinFitnessProgramForIsland(int nIslandIndex)
{
// Sample the first program as a starting fitness
BaseProgram progMinFitness = this.m_engEngine.Population[nIslandIndex][0];
float fMinFitness = progMinFitness.m_fFitness;
// Go through all the programs and get the program with the
// Minimal fitness
foreach (BaseProgram progProgram in this.m_engEngine.Population[nIslandIndex])
{
// If the current program has least fitness than all the rest so far
// Then it's the most minimal fitness program.
if (fMinFitness > progProgram.m_fFitness)
{
fMinFitness = progProgram.m_fFitness;
progMinFitness = progProgram;
}
}
return(progMinFitness);
}
/// <summary>
/// Creates a random node in the tree. The function is recursive, and
/// Creates a random node. Which means, a random function or variable will
/// Be selected . If a function is selected, then another nodes for the
/// Function will be created. If a variable will be selected, then
/// The tree will stop evolving at this branch.
/// </summary>
/// <param name="nCurrentDepth">The current tree depth</param>
/// <returns>A random tree node</returns>
private Node CreateRandomNode(int nCurrentDepth, BaseProgram baseProgOwner, ArrayList arrRandomableTypes)
{
TreeProgram progOwner = (TreeProgram)baseProgOwner;
// The chosen index in all the types array, to choose some random thing,
// Either variable of function, to insert as a node.
int nChosenTypeIndex = GlobalRandom.m_rndRandom.Next(arrRandomableTypes.Count);
object objChosenType = arrRandomableTypes[nChosenTypeIndex];
// If we are above the tree limit, choose randomly until we select a variable.
bool fFoundLeaf = false;
while ((nCurrentDepth > this.m_nMaxInitialTreeDepth) &&
(fFoundLeaf == false))
{
nChosenTypeIndex = GlobalRandom.m_rndRandom.Next(arrRandomableTypes.Count);
objChosenType = arrRandomableTypes[nChosenTypeIndex];
if (objChosenType is FunctionType)
{
if (((FunctionType)objChosenType).NumberOfArguments == 0)
{
fFoundLeaf = true;
}
}
else // The type is variable
{
fFoundLeaf = true;
}
}
// If we are below the initial tree limit, choose randomly until we select
// A function.
bool fFoundBranch = false;
while ((nCurrentDepth < this.m_nMinInitialTreeDepth) &&
(fFoundBranch == false))
{
nChosenTypeIndex = GlobalRandom.m_rndRandom.Next(arrRandomableTypes.Count);
objChosenType = arrRandomableTypes[nChosenTypeIndex];
if (objChosenType is FunctionType)
{
if (((FunctionType)objChosenType).NumberOfArguments > 0)
{
fFoundBranch = true;
}
}
}
// If the object chosen is a variable, create a new VariableNode
if (objChosenType is Variable)
{
Variable vlVariable = (Variable)objChosenType;
return(new VariableNode(vlVariable, progOwner));
}
// If the object chosen is a value, create a new ValueNode
else if (objChosenType is Value)
{
Value vlValue = (Value)objChosenType;
return(new ValueNode(vlValue));
}
// If the object chosen is a RandomMacro, create a new ValueNode which
// Will be randomized.
else if (objChosenType is RandomMacro)
{
return(new ValueNode(((RandomMacro)objChosenType).ReturnValue()));
}
// If the object chosen is a function, then create a function and also
// Create trees for that function.
else if (objChosenType is Function)
{
FunctionNode fncNewNode = new FunctionNode();
Function funcChosenFunction = (Function)objChosenType;
fncNewNode.m_funcFunction = funcChosenFunction;
fncNewNode.m_arrSons = new Node[funcChosenFunction.NumberOfArguments];
for (int nSonIndex = 0;
nSonIndex < fncNewNode.m_arrSons.Length;
nSonIndex++)
{
fncNewNode.m_arrSons[nSonIndex] =
CreateRandomNode(nCurrentDepth + 1, progOwner, arrRandomableTypes);
}
return(fncNewNode);
}
// We will never normally reach here.
return(null);
}
protected override void RunProgram(BaseProgram progProgram)
{
this.EvalFitnessForProgramEvent((TreeProgram)progProgram, this);
}
