costmatrix.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;

import java.util.Collection;

import com.prudsys.pdm.Core.CategoricalAttribute;
import com.prudsys.pdm.Core.Category;
import com.prudsys.pdm.Core.MiningException;

/**
  * Defines cost of misclassifications. <p>
  *
  * A CostMatrix is used to measure the cost of predictions made by a
  * supervised model. The value at entry (j, k) of a cost matrix specifies
  * the user valuation of predicting target class j when target class k is
  * the truth. <p>
  *
  * By default, returns 0 on the diagonal and 1 on the off-diagonal
  * if no other value has been set.
  *
  * From CWM Data Mining. <p>
  *
  * Superclasses:
  * <ul>
  *   <li> Class
  * </ul>
  */
public class CostMatrix extends com.prudsys.pdm.Cwm.Core.Class
{
    // -----------------------------------------------------------------------
    //  Variables declarations
    // -----------------------------------------------------------------------
    /** Reference to classification settings. Not used. */
    public ClassificationSettings settings[];

    /** Number of rows (=columns) of the matrix. */
    private int size = 0;

    /** Categorical attribute used as container for categories. */
    private CategoricalAttribute categories = new CategoricalAttribute();

    /** Cost values of the matrix. */
    private double[][] values = null;

    // -----------------------------------------------------------------------
    //  Constructors
    // -----------------------------------------------------------------------
    /**
     * Empty constructor.
     */
    public CostMatrix()
    {
       this(0);
    }

    /**
     * Constructor with given number of rows.
     *
     * @param size number of rows (= #coumns) of cost matrix
     */
    public CostMatrix(int size) {

      this.size   = size;
      this.values = new double[size][size];
    }

    // -----------------------------------------------------------------------
    //  Getter and setter methods
    // -----------------------------------------------------------------------
    /**
     * Returns size of cost matrix, i.e. the maximum number of categories
     * ( = #rows = #columns) that build up the matrix.
     *
     * @return size of cost matrix
     */
    public int getSize() {

      return size;
    }

    /**
     * Set size of cost matrix, i.e. the maximum number of categories
     * ( = #rows = #columns) that build up the matrix.
     *
     * @param size new size of cost matrix
     */
    public void setSize(int size) {

      this.size   = size;
      this.values = new double[size][size];
      categories.removeValues();
    }

    /**
     * Returns collection of all categories of the cost matrix.
     *
     * @return categories of cost matrix
     */
    public Collection getCategories() {

      return categories.getValues();
    }

    /**
     * Sets new cost value for category pair. If a category is used for
     * the first time, it is dynamically added - supposed the number of
     * categories does not exceed the size. In the latter case an exception
     * is thrown.
     *
     * @param actualTarget actual target value
     * @param predictedTarget predicted target value
     * @param cost costs of misprediction
     * @throws MiningException unknown category that can't be used because
     * already size of matrix is reached
     */
    public void setValue(Category actualTarget, Category predictedTarget, double cost)
        throws MiningException {

      if ( categories.getCategoriesNumber() == 0 )
        throw new MiningException("size of matrix is zero");

      int ncatt    = categories.getCategoriesNumber();
      double kact  = categories.getKey(actualTarget);
      double kpred = categories.getKey(predictedTarget);

      if ( (Category.isMissingValue(kact) || Category.isMissingValue(kpred)) && ncatt == size)
        throw new MiningException("can't set value for unknown category since alraedy at bounds");
      if ( (Category.isMissingValue(kact) && Category.isMissingValue(kpred)) && ncatt == size-1)
        throw new MiningException("can't set value for unknown categories since alraedy at bounds");

      if ( Category.isMissingValue(kact)  ) kact  = categories.addCategory(actualTarget);
      if ( Category.isMissingValue(kpred) ) kpred = categories.addCategory(predictedTarget);

      values[ (int) kact ][ (int) kpred ] = cost;
    }

    /**
     * Returns cost value for category pair.
     *
     * @param actualTarget actual target value
     * @param predictedTarget predicted target value
     * @return cost costs of misprediction
     * @throws MiningException unknown category doesn't belong to cost matrix
     */
    public double getValue(Category actualTarget, Category predictedTarget)
        throws MiningException {

      double kact  = categories.getKey(actualTarget);
      double kpred = categories.getKey(predictedTarget);

      if ( Category.isMissingValue(kact) || Category.isMissingValue(kpred) )
        throw new MiningException("category doesn't belong to cost matrix");

      return values[ (int) kact ][ (int) kpred ];
    }
}