private static TreeNode GetRootNode(DataTable data, string edge)
{
var attributes = new List <MyAttribute>();
var highestInformationGainIndex = -1;
var highestInformationGain = double.MinValue;
// Get all names, amount of attributes and attributes for every column
for (var i = 0; i < data.Columns.Count - 1; i++)
{
var differentAttributenames = MyAttribute.GetDifferentAttributeNamesOfColumn(data, i);
attributes.Add(new MyAttribute(data.Columns[i].ToString(), differentAttributenames));
}
// Calculate Entropy (S)
var tableEntropy = CalculateTableEntropy(data);
for (var i = 0; i < attributes.Count; i++)
{
attributes[i].InformationGain = GetGainForAllAttributes(data, i, tableEntropy);
if (attributes[i].InformationGain > highestInformationGain)
{
highestInformationGain = attributes[i].InformationGain;
highestInformationGainIndex = i;
}
}
try
{
return(new TreeNode(attributes[highestInformationGainIndex].Name, highestInformationGainIndex, attributes[highestInformationGainIndex], edge));
}catch (Exception e)
{
return(null);
}
}
public TreeNode(string name, int tableIndex, MyAttribute nodeAttribute, string edge)
{
Name = name;
TableIndex = tableIndex;
NodeAttribute = nodeAttribute;
ChildNodes = new List <TreeNode>();
Edge = edge;
}