| package com.yahoo.labs.samoa.learners.classifiers.trees; |
| |
| /* |
| * #%L |
| * SAMOA |
| * %% |
| * Copyright (C) 2013 Yahoo! Inc. |
| * %% |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * #L% |
| */ |
| |
| import com.yahoo.labs.samoa.core.DoubleVector; |
| import com.yahoo.labs.samoa.instances.Instance; |
| |
| /** |
| * Abstract class that represents a node in the tree model. |
| * |
| * @author Arinto Murdopo |
| * |
| */ |
| abstract class Node implements java.io.Serializable { |
| |
| private static final long serialVersionUID = 4008521239214180548L; |
| |
| protected final DoubleVector observedClassDistribution; |
| |
| /** |
| * Method to route/filter an instance into its corresponding leaf. This method will be invoked recursively. |
| * |
| * @param inst |
| * Instance to be routed |
| * @param parent |
| * Parent of the current node |
| * @param parentBranch |
| * The index of the current node in the parent |
| * @return FoundNode which is the data structure to represent the resulting leaf. |
| */ |
| abstract FoundNode filterInstanceToLeaf(Instance inst, SplitNode parent, int parentBranch); |
| |
| /** |
| * Method to return the predicted class of the instance based on the statistic inside the node. |
| * |
| * @param inst |
| * To-be-predicted instance |
| * @param map |
| * ModelAggregatorProcessor |
| * @return The prediction result in the form of class distribution |
| */ |
| abstract double[] getClassVotes(Instance inst, ModelAggregatorProcessor map); |
| |
| /** |
| * Method to check whether the node is a leaf node or not. |
| * |
| * @return Boolean flag to indicate whether the node is a leaf or not |
| */ |
| abstract boolean isLeaf(); |
| |
| /** |
| * Constructor of the tree node |
| * |
| * @param classObservation |
| * distribution of the observed classes. |
| */ |
| protected Node(double[] classObservation) { |
| this.observedClassDistribution = new DoubleVector(classObservation); |
| } |
| |
| /** |
| * Getter method for the class distribution |
| * |
| * @return Observed class distribution |
| */ |
| protected double[] getObservedClassDistribution() { |
| return this.observedClassDistribution.getArrayCopy(); |
| } |
| |
| /** |
| * A method to check whether the class distribution only consists of one class or not. |
| * |
| * @return Flag whether class distribution is pure or not. |
| */ |
| protected boolean observedClassDistributionIsPure() { |
| return (observedClassDistribution.numNonZeroEntries() < 2); |
| } |
| |
| protected void describeSubtree(ModelAggregatorProcessor modelAggrProc, StringBuilder out, int indent) { |
| // TODO: implement method to gracefully define the tree |
| } |
| |
| // TODO: calculate promise for limiting the model based on the memory size |
| // double calculatePromise(); |
| } |