/*
* 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.learner.clustering.hierarchical;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.condition.InnerOperatorCondition;
import com.rapidminer.operator.condition.SimpleChainInnerOperatorCondition;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeInt;
import com.rapidminer.parameter.UndefinedParameterError;
import com.rapidminer.tools.RandomGenerator;
/**
* Creates a random top down clustering. Used for testing purposes.
*
* @author Michael Wurst
* @version $Id: RandomTopDownClustering.java,v 1.6 2008/09/12 10:30:07 tobiasmalbrecht Exp $
*/
public class RandomTopDownClustering extends TopDownClustering {
/** The parameter name for "the maximal number of clusters at each level" */
public static final String PARAMETER_MAX_K = "max_k";
public RandomTopDownClustering(OperatorDescription description) {
super(description);
}
protected List<List<String>> clusterItems(List<String> items) throws UndefinedParameterError {
int maxNumClusters = getParameterAsInt(PARAMETER_MAX_K);
List<List<String>> result = new LinkedList<List<String>>();
int numClusters = 0;
if (maxNumClusters > items.size())
numClusters = items.size();
else
numClusters = maxNumClusters;
int diff = items.size() / numClusters;
List<String> items_ = new ArrayList<String>(items);
Random rng = RandomGenerator.getGlobalRandomGenerator();
int i = 0;
List<String> subList = null;
while (i < items.size()) {
int randomIndex = rng.nextInt(items_.size());
String item = items_.get(randomIndex);
items_.remove(randomIndex);
if ((i % diff) == 0) {
subList = new ArrayList<String>();
result.add(subList);
}
subList.add(item);
i++;
}
return result;
}
public InnerOperatorCondition getInnerOperatorCondition() {
return new SimpleChainInnerOperatorCondition();
}
public int getMaxNumberOfInnerOperators() {
return 0;
}
public int getMinNumberOfInnerOperators() {
return 0;
}
public List<ParameterType> getParameterTypes() {
List<ParameterType> types = super.getParameterTypes();
ParameterType type = new ParameterTypeInt(PARAMETER_MAX_K, "the maximal number of clusters at each level", 2, Integer.MAX_VALUE, 2);
type.setExpert(false);
types.add(type);
return types;
}
}