resortstreamvectors.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 Michael Thess
  * @version 1.0
  */
package com.prudsys.pdm.Transform.Special;

import java.util.Random;

import com.prudsys.pdm.Core.MiningDataSpecification;
import com.prudsys.pdm.Core.MiningException;
import com.prudsys.pdm.Input.MiningFilterStream;
import com.prudsys.pdm.Input.MiningInputStream;
import com.prudsys.pdm.Transform.MiningStreamTransformer;
import com.prudsys.pdm.Utils.IntVector;

/**
 * Resorts the vectors of a mining input stream using a randomization
 * function. Seed value can be given as parameter.
 *
 * @see MiningInputStream
 * @see MiningFilterStream
 */
public class ResortStreamVectors implements MiningStreamTransformer
{
    // -----------------------------------------------------------------------
    //  Variables declarations
    // -----------------------------------------------------------------------
    /** Seed value for random generator. */
    private long seed = 64;

    // -----------------------------------------------------------------------
    //  Constructor
    // -----------------------------------------------------------------------
    /**
     * Empty constructor.
     */
    public ResortStreamVectors() {

    }

    // -----------------------------------------------------------------------
    //  Getter and setter methods
    // -----------------------------------------------------------------------
    /**
     * Returns seed number of random generator.
     *
     * @return seed number of random generator
     */
    public long getSeed()
    {
      return seed;
    }

    /**
     * Sets seed number of random generator.
     *
     * @param seed new seed number of random generator
     */
    public void setSeed(long seed)
    {
      this.seed = seed;
    }

    // -----------------------------------------------------------------------
    //  Transformation methods
    // -----------------------------------------------------------------------
  /**
   * Resorts mining input stream to another one. The
   * targetStream must contain an updatable mining stream.
   *
   * @param sourceStream mining stream used as source to copy, must support
   * free cursor access
   * @param targetStream mining stream used as target of copy
   * @return number of vectors of transformation
   * @exception MiningException cannot execute transformation
   */
  public int transform( MiningInputStream sourceStream, MiningInputStream targetStream )
    throws MiningException {

    // Copy metadata:
    MiningDataSpecification metaDataSource = sourceStream.getMetaData();
    targetStream.updateSetMetaData( metaDataSource );

    // Use auxiliary vector for swapping assignment:
    Random rand = new Random(seed);
    int nVec = sourceStream.getVectorsNumber();
    IntVector assVec = new IntVector();
    for (int i = 0; i < nVec; i++)
      assVec.addElement(i);
    for (int i = nVec - 1; i > 0; i--) {
      int i2 = rand.nextInt(i+1);
      int vt = assVec.IntegerAt(i);
      assVec.setElementAt(assVec.IntegerAt(i2), i);
      assVec.setElementAt(vt, i2);
    };

    // Copy vectors:
    sourceStream.reset();
    targetStream.updateRemoveAllVectors();
    for (int i = 0; i < nVec; i++) {
      targetStream.updateAppendVector( sourceStream.read( assVec.IntegerAt(i) ) );
    };

    return nVec;
  }
}