/*
* RapidMiner
*
* Copyright (C) 2001-2008 by Rapid-I and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapid-i.com
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.operator.preprocessing.filter;
import java.util.ArrayList;
import java.util.List;
import com.rapidminer.example.Attribute;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.table.DataRow;
import com.rapidminer.example.table.DataRowReader;
import com.rapidminer.example.table.ExampleTable;
import com.rapidminer.example.table.MemoryExampleTable;
import com.rapidminer.operator.IOObject;
import com.rapidminer.operator.Operator;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
/** This operator creates a new, shuffled ExampleSet by making <em>a new copy</em>
* of the exampletable in main memory!
* Caution! System may run out of memory, if exampletable is too large.
*
* @author Sebastian Land, Ingo Mierswa
* @version $Id: PermutationOperator.java,v 1.4 2008/07/07 07:06:39 ingomierswa Exp $
*/
public class PermutationOperator extends Operator {
public PermutationOperator(OperatorDescription description) {
super(description);
}
public IOObject[] apply() throws OperatorException {
ExampleSet exampleSet = getInput(ExampleSet.class);
ExampleTable table = exampleSet.getExampleTable();
// generate attribute list (clones)
List<Attribute> attributeList = new ArrayList<Attribute>();
for (Attribute attribute : exampleSet.getAttributes()) {
attributeList.add((Attribute)attribute.clone());
}
int toCopy = table.size();
// generate new ExampleTable of size of old table
MemoryExampleTable shuffledTable = new MemoryExampleTable(attributeList);
// copy all dataRows
DataRow[] isCopied = new DataRow[toCopy];
int areCopied = 0;
DataRowReader reader = table.getDataRowReader();
while (areCopied < toCopy) {
int currentRow = (int)Math.round((Math.random()*(toCopy-1)));
if (isCopied[currentRow] == null){
isCopied[currentRow] = reader.next();
// increase counter of copied rows
areCopied++;
}
checkForStop();
}
for (int i=0; i < toCopy; i++) {
shuffledTable.addDataRow(isCopied[i]);
}
return new IOObject[] { shuffledTable.createExampleSet(exampleSet.getAttributes().specialAttributes()) };
}
public Class<?>[] getInputClasses() {
return new Class[] { ExampleSet.class };
}
public Class<?>[] getOutputClasses() {
return new Class[] { ExampleSet.class };
}
}