/*
 * 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.ode.nonstiff;

import org.apache.commons.math.ode.FirstOrderDifferentialEquations;
import org.apache.commons.math.ode.events.EventHandler;

public class StepProblem implements FirstOrderDifferentialEquations, EventHandler {

	public StepProblem(double rateBefore, double rateAfter, double switchTime) {
		this.rateAfter = rateAfter;
		this.switchTime = switchTime;
		setRate(rateBefore);
	}

	public void computeDerivatives(double t, double[] y, double[] yDot) {
		yDot[0] = rate;
	}

	public int getDimension() {
		return 1;
	}

	public void setRate(double rate) {
		this.rate = rate;
	}

	public int eventOccurred(double t, double[] y, boolean increasing) {
		setRate(rateAfter);
		return RESET_DERIVATIVES;
	}

	public double g(double t, double[] y) {
		return t - switchTime;
	}

	public void resetState(double t, double[] y) {
	}

	private double rate;
	private double rateAfter;
	private double switchTime;

	private static final long serialVersionUID = 7590601995477504318L;

}
