private void Mutate(MathExpressionTree expression)
{
MathExpressionNode randomNode = expression.GetRandomNode();
randomNode.SubstiteValue(randomNode.IsLeaf ?
stohasticGenerator.GetRandomOperand()
: stohasticGenerator.GetRandomOperator(randomNode.LeftChild, randomNode.RightChild));
}
public MathExpressionTree GenerateIndividual()
{
MathExpressionTree validExpression;
do
{
int operandsCount = stohasticGenerator.OperandsCount();
List <MathExpressionNode> operatorsAndOperands = Enumerable.Range(0, 2 * operandsCount - 1)
.Select(x => x % 2 == 0 ? stohasticGenerator.GetRandomOperand() : stohasticGenerator.GetRandomOperator())
.ToList();
MathExpressionNode root = operatorsAndOperands.Where(x => !x.IsLeaf)
.OrderBy(x => Guid.NewGuid())
.First();
MathExpressionNode getGenome(List <MathExpressionNode> elements, MathExpressionNode parent, MathExpressionNode rootNode = null)
{
if (elements.Count == 0)
{
return(null);
}
MathExpressionNode currentNode = (rootNode ?? elements.FirstOrDefault(x => !x.IsLeaf)) ?? elements.First();
currentNode.Parent = parent;
if (!currentNode.IsLeaf)
{
int currentNodeIndex = elements.IndexOf(currentNode);
currentNode.LeftChild = getGenome(elements.Take(currentNodeIndex).ToList(), currentNode);
currentNode.RightChild = getGenome(elements.Skip(currentNodeIndex + 1).ToList(), currentNode);
}
return(currentNode);
}
validExpression = new MathExpressionTree(getGenome(operatorsAndOperands, null, root));
} while (!validExpression.IsValidExpression());
return(validExpression);
}
