/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.math.analysis;

import org.apache.commons.math.FunctionEvaluationException;

/**
 * Auxillary class for testing solvers.
 *
 * The function is extraordinarily well behaved around zero roots: it has an
 * inflection point there (second order derivative is zero), which means linear
 * approximation (Regula Falsi) will converge quadratically.
 * 
 * @version $Revision$ $Date$
 */
public class SinFunction implements DifferentiableUnivariateRealFunction {

	/*
	 * Evaluate sinus fuction.
	 * 
	 * @see org.apache.commons.math.UnivariateRealFunction#value(double)
	 */
	public double value(double x) throws FunctionEvaluationException {
		return Math.sin(x);
	}

	/*
	 * First derivative of sinus function
	 */
	public UnivariateRealFunction derivative() {
		return new UnivariateRealFunction() {
			public double value(double x) throws FunctionEvaluationException {
				return Math.cos(x);
			}
		};
	}

}
