public TreeAttributeCollection GetValidAttributeCollection() { TreeAttributeCollection returnCollection = new TreeAttributeCollection(); foreach (DataColumn column in this.Columns) { TreeAttribute currentAttribute = new TreeAttribute(column.ColumnName, GetValuesFromColumn(column.ColumnName)); if (returnCollection.ContainsAttribute(currentAttribute) || currentAttribute.AttributeName.ToUpper().Trim() == "EXPLOSIVE") { continue; } returnCollection.Add(currentAttribute); } return(returnCollection); }
private TreeAttribute getBestAttribute(DataTable samples, TreeAttributeCollection attributes) { double maxGain = 0.0; TreeAttribute result = null; foreach (TreeAttribute attribute in attributes) { double aux = gain(samples, attribute); if (aux > maxGain) { maxGain = aux; result = attribute; } } return(result); }
public TreeNode(TreeAttribute attribute) { if (attribute != null && attribute.PossibleValues != null) { _children = new TreeNodeCollection(); for (int i = 0; i < attribute.PossibleValues.Count; i++) { _children.Add(null); } } else { _children = new TreeNodeCollection(); _children.Add(null); } _attribute = attribute; }
private double gain(DataTable samples, TreeAttribute attribute) { PossibleValueCollection values = attribute.PossibleValues; double sum = 0.0; for (int i = 0; i < values.Count; i++) { int positives, negatives; positives = negatives = 0; getValuesToAttribute(samples, attribute, values[i], out positives, out negatives); double entropy = calculateEntropy(positives, negatives); sum += -(double)(positives + negatives) / mTotal * entropy; } return(mEntropySet + sum); }
private void getValuesToAttribute(DataTable samples, TreeAttribute attribute, string value, out int positives, out int negatives) { positives = 0; negatives = 0; foreach (DataRow aRow in samples.Rows) { if (((string)aRow[attribute.AttributeName] == value)) { if (aRow[mTargetAttribute].ToString().Trim().ToUpper() == "TRUE") { positives++; } else { negatives++; } } } }
private TreeNode buildTree(DataTable samples, string targetAttribute, TreeAttributeCollection attributes) { if (samples == null) { return(new TreeNode(new OutcomeTreeAttribute(targetAttribute))); } if (allSamplesArePositive(samples, targetAttribute) == true) { return(new TreeNode(new OutcomeTreeAttribute(true))); } if (allSamplesAreNegative(samples, targetAttribute) == true) { return(new TreeNode(new OutcomeTreeAttribute(false))); } if (attributes.Count == 0) { return(new TreeNode(new OutcomeTreeAttribute(getMostCommonValue(samples, targetAttribute)))); } mTotal = samples.Rows.Count; mTargetAttribute = targetAttribute; mTotalPositives = countTotalPositives(samples); mEntropySet = calculateEntropy(mTotalPositives, mTotal - mTotalPositives); TreeAttribute bestAttribute = getBestAttribute(samples, attributes); TreeNode root = new TreeNode(bestAttribute); if (bestAttribute == null) { return(root); } DataTable aSample = samples.Clone(); foreach (string value in bestAttribute.PossibleValues) { aSample.Rows.Clear(); DataRow[] rows = samples.Select(bestAttribute.AttributeName + " = " + "'" + value + "'"); foreach (DataRow row in rows) { aSample.Rows.Add(row.ItemArray); } TreeAttributeCollection aAttributes = new TreeAttributeCollection(); //ArrayList aAttributes = new ArrayList(attributes.Count - 1); for (int i = 0; i < attributes.Count; i++) { if (attributes[i].AttributeName != bestAttribute.AttributeName) { aAttributes.Add(attributes[i]); } } if (aSample.Rows.Count == 0) { return(new TreeNode(new OutcomeTreeAttribute(getMostCommonValue(aSample, targetAttribute)))); } else { DecisionTree dc3 = new DecisionTree(); TreeNode ChildNode = dc3.mountTree(aSample, targetAttribute, aAttributes); root.AddTreeNode(ChildNode, value); } } return(root); }