public int CountNodes(Node node)
{
int result = 1;
if (node.GetLeft() != null)
result += CountNodes(node.GetLeft());
if (node.GetRight() != null)
result += CountNodes(node.GetRight());
return result;
}
public int CountLeafLastNodes(Node node)
{
int result = 0;
if (node.GetLeft() != null)
result += CountLeafLastNodes(node.GetLeft());
if (node.GetRight() != null)
result += CountLeafLastNodes(node.GetRight());
if (node.GetLeft() == null && node.GetRight() == null)
return node.leaf;
return result;
}
public void Algorithm(double[][] dataInput, Node node)
{
/*
* Choose class for node if is the case.
*/
node.classType = sameClass(dataInput);
if (node.classType != -1)
{
node.leaf = dataInput.Length;
return;
}
node.classType = sameAtributtes(dataInput);
if (node.classType != -1)
{
node.leaf = dataInput.Length;
return;
}
/*
* Choose best axis-parallel split node for dataInput.
*/
bestAxisParallel(dataInput, node);
/*
* Apply OC1
*/
Node auxNode = (Node)node.Clone();
for (int i = 0; i < R; i++)
{
if (i > 0)
auxNode.Random();
step1:
double initialGain = gain(dataInput, node); // Gain for better node.
for (int d = 0; d < dataInput[0].Length; d++)
{
pertube(d, auxNode, dataInput);
if (gain(dataInput, auxNode) > initialGain)
{
node.SetNode(auxNode);
break;
}
}
// step 2
initialGain = gain(dataInput, node);
for (int j = 0; j < J; j++)
{
Random rand = new Random();
int direction = rand.Next(dataInput[0].Length - 1);
pertube(direction, auxNode, dataInput);
if (gain(dataInput, auxNode) > initialGain)
{
node.SetNode(auxNode);
goto step1;
}
}
if (gain(dataInput, auxNode) > gain(dataInput, node))
node.SetNode(auxNode);
}
/*
* Recursive Algorithm for each branch for node.
*/
Node left = new Node(new double[dataInput[0].Length], 0);
Node right = new Node(new double[dataInput[0].Length], 0);
node.SetLeft(left);
node.SetRight(right);
List<double[]>[] data = divideData(dataInput, node);
Algorithm(data[0].ToArray(), node.GetLeft());
Algorithm(data[1].ToArray(), node.GetRight());
}
private void pertube(int m, Node node, double[][] dataInput)
{
if (!node.ActiveAtributtes[m])
return;
Node auxNode = (Node)node.Clone();
double[] U = new double[dataInput.Length];
for (int i = 0; i < dataInput.Length; i++)
U[i] = Math.Min((node.weights[m] * dataInput[i][m] - node.Evaluate(dataInput[i])) / dataInput[i][m], 0);
Array.Sort(U);
int bestA = 0;
int dif = Int16.MaxValue;
for (int i = 0; i < U.Length; i++)
{
int positive = 0;
int negative = 0;
for (int j = 0; j < U.Length; j++)
{
if (j <= i && U[j] <= 0)
negative++;
else if (j > i && U[j] > 0)
positive++;
}
if (Math.Abs(positive - negative) < dif)
{
dif = Math.Abs(positive - negative);
bestA = i;
}
}
auxNode.weights[m] = U[bestA];
if (gain(dataInput, auxNode) > gain(dataInput, node))
{
node.weights[m] = U.Max();
node.ResetPmove();
}
else if (gain(dataInput, auxNode) == gain(dataInput, node))
{
if(node.EvaluatePmove())
node.weights[m] = U.Max();
node.DecreasePmove();
}
}
private void bestAxisParallel(double[][] dataInput, Node n)
{
bool[] dimensionUsed = new bool[dataInput[0].Length];
dimensionUsed[dataInput[0].Length - 1] = true;
for (int k = 0; k < _k; k++)
{
int bestDimension = 0;
double bestGain = gain(dataInput, n);
for (int d = 0; d < dataInput[0].Length; d++)
{
if (!dimensionUsed[d])
{
n.weights[d] = 1;
for (int i = 0; i < dataInput.Length; i++)
{
double baias = n.baias;
n.SetBaias(dataInput[i]);
if (gain(dataInput, n) > bestGain)
{
bestDimension = d;
bestGain = gain(dataInput, n);
}
else
n.baias = baias;
}
n.weights[d] = 0;
}
}
dimensionUsed[bestDimension] = true;
n.weights[bestDimension] = 1;
n.Activate(bestDimension);
}
}
private static double gain(double[][] input, Node node)
{
double gain = entropy(input);
List<double[]>[] dataGroups = divideData(input, node);
for (int i = 0; i < 2; i++)
{
if(dataGroups[i].Count > 0)
gain -= (dataGroups[i].Count * entropy(dataGroups[i].ToArray())) / input.Length;
}
return gain;
}
/*
* data[0]: left
* data[1]: right
*/
private static List<double[]>[] divideData(double[][] input, Node node)
{
List<double[]>[] data = new List<double[]>[2];
data[0] = new List<double[]>();
data[1] = new List<double[]>();
for (int i = 0; i < input.Length; i++)
{
if (node.Evaluate(input[i]) < 0) //Curioso caso.
data[0].Add(input[i]);
else
data[1].Add(input[i]);
}
return data;
}
private void setParent(Node parent)
{
_parent = parent;
}
public void SetRight(Node right)
{
_right = right;
_right.setParent(this);
}
public void SetNode(Node input)
{
for (int i = 0; i < weights.Length; i++)
{
weights[i] = input.weights[i];
}
baias = input.baias;
}
public void SetLeft(Node left)
{
_left = left;
_left.setParent(this);
}
public DesicionTree(Node root)
{
_root = root;
}
private void Prunning(int n, Node node)
{
if (node.GetLeft() != null)
Prunning(n, node.GetLeft());
if (node.GetRight() != null)
Prunning(n, node.GetRight());
if (node.GetRight() == null && node.GetLeft() == null)
return;
if (node.GetRight() == null && node.GetLeft().leaf < n)
{
node.leaf += node.GetLeft().leaf;
node.classType = node.GetLeft().classType;
node.RemoveLeft();
}
else if (node.GetLeft() == null && node.GetRight().leaf < n)
{
node.leaf += node.GetRight().leaf;
node.classType = node.GetRight().classType;
node.RemoveRight();
}
else if (node.GetRight().leaf < n && node.GetLeft().leaf >= n)
{
node.classType = node.GetRight().classType;
node.leaf += node.GetRight().leaf;
node.RemoveRight();
}
else if (node.GetRight().leaf >= n && node.GetLeft().leaf < n)
{
node.classType = node.GetLeft().classType;
node.leaf += node.GetLeft().leaf;
node.RemoveLeft();
}
else if (node.GetRight().leaf < n && node.GetLeft().leaf < n)
{
if (node.GetRight().leaf > node.GetLeft().leaf)
node.classType = node.GetRight().classType;
else
node.classType = node.GetLeft().classType;
node.leaf += node.GetLeft().leaf + node.GetRight().leaf;
node.RemoveLeft();
node.RemoveRight();
}
}