/**
* Copyright (C) 2001-2017 by RapidMiner and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapidminer.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.tools.expression.internal.function.mathematical;
import com.rapidminer.tools.Ontology;
import com.rapidminer.tools.expression.ExpressionType;
import com.rapidminer.tools.expression.FunctionInputException;
import com.rapidminer.tools.expression.internal.function.Abstract1DoubleInputFunction;
/**
* A {@link Function} computing signum of a number. Returns +1, if the value is zero.
*
* @author Marcel Seifert
*
*/
public class Signum extends Abstract1DoubleInputFunction {
public Signum() {
super("mathematical.sgn", Ontology.NUMERICAL);
}
@Override
protected double compute(double value) {
double sgn = Math.signum(value);
return sgn;
}
@Override
protected ExpressionType computeType(ExpressionType... inputTypes) {
ExpressionType input = inputTypes[0];
if (input == ExpressionType.INTEGER || input == ExpressionType.DOUBLE) {
return ExpressionType.INTEGER;
} else {
throw new FunctionInputException("expression_parser.function_wrong_type", getFunctionName(), "numerical");
}
}
}