Commons Math example source code file (StepProblem.java)

This example Commons Math source code file (StepProblem.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Math tags/keywords

eventhandler, eventhandler, firstorderdifferentialequations, firstorderdifferentialequations, reset_derivatives, reset_derivatives, stepproblem, stepproblem

The Commons Math StepProblem.java source code

/*
 * 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;

}