/**
 * Copyright 2010 Neuroph Project http://neuroph.sourceforge.net
 *
 * Licensed 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.neuroph.contrib.samples.timeseries;

/**
 * Very simple class which just wraps up the generation of a sine wave at one degree steps.
 * Just call getNextSample each time you need a new sample. Class internally tracks the angle.
 * See http://neuroph.sourceforge.net/TimeSeriesPredictionTutorial.html
 *
 * @author Laura Ellen Carter-Greaves
 */

public class GenerateSineWave {

	private double frequency=1;
	private double amplitude=1;
	private double angle=0;
	private static double oneDegree=Math.PI/180;

        /**
         * Constructor for sine wave generator with specified frequency and amplitude
         * @param frequency sine wave frequency
         * @param amplitude sine wave amplitude
         */
	GenerateSineWave(double frequency, double amplitude){
		this.frequency=frequency;
		this.amplitude=amplitude;
	}

        /**
         * Gets next sampling value for the sine wave
         * @return next sampling value for the sine wave
         */
	public double getNextSample(){
		angle+=oneDegree;
		return Math.sin(frequency*angle)*amplitude;
	}
}