/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2011 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.normalization;

import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.Statistics;
import com.rapidminer.operator.Operator;
import com.rapidminer.operator.UserError;
import com.rapidminer.operator.ports.InputPort;
import com.rapidminer.operator.ports.metadata.AttributeMetaData;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.ports.metadata.MDReal;
import com.rapidminer.operator.ports.metadata.SetRelation;
import com.rapidminer.parameter.ParameterHandler;
import com.rapidminer.parameter.UndefinedParameterError;
import com.rapidminer.tools.container.Tupel;
import com.rapidminer.tools.math.container.Range;

/**
 * The normalization method for the Z-Transformation
 * 
 * @author Sebastian Land
 */
public class ZTransformationNormalizationMethod extends AbstractNormalizationMethod {

	@Override
	public Collection<AttributeMetaData> modifyAttributeMetaData(ExampleSetMetaData emd, AttributeMetaData amd, InputPort exampleSetInputPort, ParameterHandler parameterHandler) throws UndefinedParameterError {
		amd.setMean(new MDReal((double) 0));
		amd.setValueRange(new Range(Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY), SetRelation.SUBSET);
		return Collections.singleton(amd);
	}

	@Override
	public AbstractNormalizationModel getNormalizationModel(ExampleSet exampleSet, Operator operator) throws UserError {
		// Z-Transformation
		exampleSet.recalculateAllAttributeStatistics();
		HashMap<String, Tupel<Double, Double>> attributeMeanVarianceMap = new HashMap<String, Tupel<Double, Double>>(); 
		for (Attribute attribute : exampleSet.getAttributes()) {
			if (attribute.isNumerical()) {
				attributeMeanVarianceMap.put(attribute.getName(), new Tupel<Double, Double>( 
						exampleSet.getStatistics(attribute, Statistics.AVERAGE),
						exampleSet.getStatistics(attribute, Statistics.VARIANCE)));
			}
		}
		ZTransformationModel model = new ZTransformationModel(exampleSet, attributeMeanVarianceMap);
		return model;
	}

	@Override
	public String getName() {
		return "Z-transformation";
	}

}