Accord.Genetic.GPTreeChromosome.Mutate C# (CSharp) Method

        public override void Mutate()
        {
            var rand = Generator.Random;

            // current tree level
            int currentLevel = 0;

            // current node
            GPTreeNode node = root;

            for (; ; )
            {
                // regenerate node if it does not have children
                if (node.Children == null)
                {
                    if (currentLevel == maxLevel)
                    {
                        // we reached maximum possible level, so the gene
                        // can be an argument only
                        node.Gene.Generate(GPGeneType.Argument);
                    }
                    else
                    {
                        // generate subtree
                        Generate(node, rand.Next(maxLevel - currentLevel));
                    }
                    break;
                }

                // if it is a function node, than we need to get a decision, about
                // mutation point - the node itself or one of its children
                int r = rand.Next(node.Gene.ArgumentsCount + 1);

                if (r == node.Gene.ArgumentsCount)
                {
                    // node itself should be regenerated
                    node.Gene.Generate();

                    // check current type
                    if (node.Gene.GeneType == GPGeneType.Argument)
                    {
                        node.Children = null;
                    }
                    else
                    {
                        // create children's list if it was absent
                        if (node.Children == null)
                            node.Children = new List<GPTreeNode>();

                        // check for missing or extra children
                        if (node.Children.Count != node.Gene.ArgumentsCount)
                        {
                            if (node.Children.Count > node.Gene.ArgumentsCount)
                            {
                                // remove extra children
                                node.Children.RemoveRange(node.Gene.ArgumentsCount, node.Children.Count - node.Gene.ArgumentsCount);
                            }
                            else
                            {
                                // add missing children
                                for (int i = node.Children.Count; i < node.Gene.ArgumentsCount; i++)
                                {
                                    // create new child
                                    GPTreeNode child = new GPTreeNode();
                                    Generate(child, rand.Next(maxLevel - currentLevel));
                                    // add the new child
                                    node.Children.Add(child);
                                }
                            }
                        }
                    }
                    break;
                }

                // mutation goes further to one of the children
                node = (GPTreeNode)node.Children[r];
                currentLevel++;
            }
        }