public void Clear()
{
mRootNode = DecisionTreeMethods.CreateRootNode <T>(this);
mRootNode.HandleCost += (gain, feature_name) =>
{
if (HandleCost != null)
{
return(HandleCost(gain, feature_name));
}
return(gain);
};
}
/// <summary>
/// split for the root node
/// </summary>
public void Split(HashSet <string> feature_names, IEnumerable <T> data_store)
{
DecisionTreePartition <T> root_partition = DecisionTreePartition <T> .Create(this, data_store);
DecisionTreeMethods.Split <T>(root_partition, feature_names, (gain, feature_name) =>
{
if (HandleCost != null)
{
return(HandleCost(gain, feature_name));
}
return(gain);
});
}
public static Dictionary <string, DecisionTreePartition <T> > SplitPartitionByFeatureVariable <T>(DecisionTreePartition <T> partition, string variable_name, DoAttributeCostGainHandle handle_cost)
where T : DDataRecord
{
IEnumerable <T> data_store = partition.DataStore;
DecisionTreeNode <T> tree_node = partition.TreeNode;
Dictionary <string, DecisionTreePartition <T> > sub_partitions = new Dictionary <string, DecisionTreePartition <T> >();
Dictionary <string, List <T> > sub_data_stores = new Dictionary <string, List <T> >();
foreach (T rec in data_store)
{
string variable_value = rec[variable_name];
List <T> sub_data_store = null;
if (sub_data_stores.ContainsKey(variable_value))
{
sub_data_store = sub_data_stores[variable_value];
}
else
{
sub_data_store = new List <T>();
sub_data_stores[variable_value] = sub_data_store;
}
sub_data_store.Add(rec);
}
foreach (string variable_value in sub_data_stores.Keys)
{
List <T> sub_data_store = sub_data_stores[variable_value];
DecisionTreeNode <T> sub_node = DecisionTreeMethods.CreateTreeNode <T>(variable_name, variable_value, tree_node);
sub_node.HandleCost += (gain, fname) =>
{
if (handle_cost != null)
{
return(handle_cost(gain, fname));
}
return(gain);
};
sub_partitions[variable_value] = DecisionTreePartition <T> .Create(sub_node, sub_data_store);
}
return(sub_partitions);
}
public KeyValuePair <string, Dictionary <string, DecisionTreeNode <T> > > Prune()
{
Dictionary <string, DecisionTreeNode <T> > children = mChildren;
KeyValuePair <string, Dictionary <string, DecisionTreeNode <T> > > tree_info = new KeyValuePair <string, Dictionary <string, DecisionTreeNode <T> > >(
mSplitVariableName,
children);
DecisionTreePartition <T> partition = DecisionTreePartition <T> .Create(this);
Dictionary <string, DecisionTreePartition <T> > sub_partitions_by_class_variable = DecisionTreeMethods.SplitPartitionByClassVariable <T>(partition, (gain, feature_name) =>
{
if (HandleCost != null)
{
return(HandleCost(gain, feature_name));
}
return(gain);
});
partition.UpdateSubPartitions(sub_partitions_by_class_variable, DecisionTree <T> .ClassVariableName);
return(tree_info);
}
