/*
 *  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.transformation.aggregation;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.table.DoubleArrayDataRow;
import com.rapidminer.tools.Ontology;

/**
 * This class implements the Log Product Aggregation function. This will calculate the
 * logarithm of a product of a source attribute for each group. This can help in situations, where
 * the normal product would exceed the numerical range and should be used as an intermediate result.
 * 
 * This obviously only works on numbers being all greater 0.
 * 
 * @author Sebastian Land
 */
public class LogProductAggregationFunction extends NumericalAggregationFunction {

    public static final String FUNCTION_LOG_PRODUCT = "logProduct";

    public LogProductAggregationFunction(Attribute sourceAttribute, boolean ignoreMissings, boolean countOnlyDisctinct) {
        super(sourceAttribute, ignoreMissings, countOnlyDisctinct, FUNCTION_LOG_PRODUCT, FUNCTION_SEPARATOR_OPEN, FUNCTION_SEPARATOR_CLOSE);
    }

    public LogProductAggregationFunction(Attribute sourceAttribute, boolean ignoreMissings, boolean countOnlyDisctinct, String functionName, String separatorOpen, String separatorClose) {
        super(sourceAttribute, ignoreMissings, countOnlyDisctinct, functionName, separatorOpen, separatorClose);
    }

    @Override
    public Aggregator createAggregator() {
        return new LogProductAggregator(this);
    }

    @Override
    public void setDefault(Attribute attribute, DoubleArrayDataRow row) {
        row.set(attribute, 0);
    }
    
	@Override
	protected int getTargetValueType(int sourceValueType) {
		return Ontology.REAL;
	}

    @Override
    public boolean isCompatible() {
        return getSourceAttribute().isNumerical();
    }
}