MOEAFramework-2.11.src.org.moeaframework.util.tree.Sign Maven / Gradle / Ivy

/* Copyright 2009-2016 David Hadka
 *
 * This file is part of the MOEA Framework.
 *
 * The MOEA Framework is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * The MOEA Framework 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 Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the MOEA Framework.  If not, see .
 */
package org.moeaframework.util.tree;

/**
 * The node for calculating the sign of a number.  The sign of a number is
 * {@code 1} if the number is greater than zero, {@code -1} if the number is
 * less than zero, and {@code 0} if the number is equal to zero.  The inputs and
 * outputs to this node are shown below:
 * 
 * 
 *   
 *     
 *     
 *     
 *   
 *   
 *     
 *     
 *     
 *   
 *   
 *     
 *     
 *     
 *   
 * Name Type Description
Argument 1 Number The number
Return Value Number The sign of the number
 * 
 * @see Long#signum(long)
 * @see Math#signum(double)
 */
public class Sign extends Node {
	
	/**
	 * Constructs a new node for calculating the sign of a number.
	 */
	public Sign() {
		super(Number.class, Number.class);
	}
	
	@Override
	public Sign copyNode() {
		return new Sign();
	}
	
	@Override
	public Number evaluate(Environment environment) {
		return NumberArithmetic.sign(
				(Number)getArgument(0).evaluate(environment));
	}

}
Name	Type	Description
Argument 1	Number	The number
Return Value	Number	The sign of the number