/*
* 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;
/**
* This class implements a second order Runge-Kutta integrator for
* Ordinary Differential Equations.
*
* <p>This method is an explicit Runge-Kutta method, its Butcher-array
* is the following one :
* <pre>
* 0 | 0 0
* 1/2 | 1/2 0
* |----------
* | 0 1
* </pre>
* </p>
*
* @see EulerIntegrator
* @see ClassicalRungeKuttaIntegrator
* @see GillIntegrator
*
* @version $Revision: 786881 $ $Date: 2009-06-20 14:53:08 -0400 (Sat, 20 Jun 2009) $
* @since 1.2
*/
public class MidpointIntegrator extends RungeKuttaIntegrator {
/** Time steps Butcher array. */
private static final double[] c = {
1.0 / 2.0
};
/** Internal weights Butcher array. */
private static final double[][] a = {
{ 1.0 / 2.0 }
};
/** Propagation weights Butcher array. */
private static final double[] b = {
0.0, 1.0
};
/** Simple constructor.
* Build a midpoint integrator with the given step.
* @param step integration step
*/
public MidpointIntegrator(final double step) {
super("midpoint", c, a, b, new MidpointStepInterpolator(), step);
}
}
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