id3algorithm.java

一个数据挖掘软件ALPHAMINERR的整个过程的JAVA版源代码

/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/**
 * Title: XELOPES Data Mining Library
 * Description: The XELOPES library is an open platform-independent and data-source-independent library for Embedded Data Mining.
 * Copyright: Copyright (c) 2002 Prudential Systems Software GmbH
 * Company: ZSoft (www.zsoft.ru), Prudsys (www.prudsys.com)
 * @author Valentine Stepanenko ([e-mail])
 * @version 1.0
 */

package com.prudsys.pdm.Models.Classification.DecisionTree.Algorithms.Id3;

import com.prudsys.pdm.Core.MiningException;
import com.prudsys.pdm.Core.NumericAttribute;
import com.prudsys.pdm.Models.Classification.DecisionTree.DecisionTreeAlgorithm;
import com.prudsys.pdm.Models.Supervised.Classifier;

/**
 * Realization of ID3 algorithm.
 */
public class ID3Algorithm extends DecisionTreeAlgorithm
{
    private ID3TreeNode root;

    /**
     * Empty constructor.
     */
    public ID3Algorithm()
    {
    }

    /**
     * Runs ID3 algorithm.
     *
     * @throws MiningException
     */
    protected void runAlgorithm() throws MiningException
    {
        root = new ID3TreeNode( miningInputStream, metaData, target );
        root.buildTree();
    }

    /**
     * Returns decision tree classifier.
     *
     * @return decision tree classifier
     */
    protected Classifier getClassifier()
    {
        return root;
    }

    /**
     * Checks mining algorithm for completeness by calling verify method
     * of superclass. Adiitionally, it checks whether all attributes
     * are categorical.
     *
     * @throws IllegalArgumentException if some algorithm attributes are incorrect
     */
    public void verify() throws IllegalArgumentException
    {
      super.verify();

      for (int i = 0; i < metaData.getAttributesNumber(); i++)
        if (metaData.getMiningAttribute(i) instanceof NumericAttribute)
          throw new IllegalArgumentException("ID3 cannot handle numeric attributes");
    }

}