| /* |
| * 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.DerivativeException; |
| import org.apache.commons.math.ode.sampling.StepInterpolator; |
| |
| /** |
| * This class represents an interpolator over the last step during an |
| * ODE integration for the 5(4) Higham and Hall integrator. |
| * |
| * @see HighamHall54Integrator |
| * |
| * @version $Revision: 1073158 $ $Date: 2011-02-21 22:46:52 +0100 (lun. 21 févr. 2011) $ |
| * @since 1.2 |
| */ |
| |
| class HighamHall54StepInterpolator |
| extends RungeKuttaStepInterpolator { |
| |
| /** Serializable version identifier */ |
| private static final long serialVersionUID = -3583240427587318654L; |
| |
| /** Simple constructor. |
| * This constructor builds an instance that is not usable yet, the |
| * {@link |
| * org.apache.commons.math.ode.sampling.AbstractStepInterpolator#reinitialize} |
| * method should be called before using the instance in order to |
| * initialize the internal arrays. This constructor is used only |
| * in order to delay the initialization in some cases. The {@link |
| * EmbeddedRungeKuttaIntegrator} uses the prototyping design pattern |
| * to create the step interpolators by cloning an uninitialized model |
| * and later initializing the copy. |
| */ |
| public HighamHall54StepInterpolator() { |
| super(); |
| } |
| |
| /** Copy constructor. |
| * @param interpolator interpolator to copy from. The copy is a deep |
| * copy: its arrays are separated from the original arrays of the |
| * instance |
| */ |
| public HighamHall54StepInterpolator(final HighamHall54StepInterpolator interpolator) { |
| super(interpolator); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| protected StepInterpolator doCopy() { |
| return new HighamHall54StepInterpolator(this); |
| } |
| |
| |
| /** {@inheritDoc} */ |
| @Override |
| protected void computeInterpolatedStateAndDerivatives(final double theta, |
| final double oneMinusThetaH) |
| throws DerivativeException { |
| |
| final double theta2 = theta * theta; |
| |
| final double b0 = h * (-1.0/12.0 + theta * (1.0 + theta * (-15.0/4.0 + theta * (16.0/3.0 + theta * -5.0/2.0)))); |
| final double b2 = h * (-27.0/32.0 + theta2 * (459.0/32.0 + theta * (-243.0/8.0 + theta * 135.0/8.0))); |
| final double b3 = h * (4.0/3.0 + theta2 * (-22.0 + theta * (152.0/3.0 + theta * -30.0))); |
| final double b4 = h * (-125.0/96.0 + theta2 * (375.0/32.0 + theta * (-625.0/24.0 + theta * 125.0/8.0))); |
| final double b5 = h * (-5.0/48.0 + theta2 * (-5.0/16.0 + theta * 5.0/12.0)); |
| final double bDot0 = 1 + theta * (-15.0/2.0 + theta * (16.0 - 10.0 * theta)); |
| final double bDot2 = theta * (459.0/16.0 + theta * (-729.0/8.0 + 135.0/2.0 * theta)); |
| final double bDot3 = theta * (-44.0 + theta * (152.0 - 120.0 * theta)); |
| final double bDot4 = theta * (375.0/16.0 + theta * (-625.0/8.0 + 125.0/2.0 * theta)); |
| final double bDot5 = theta * 5.0/8.0 * (2 * theta - 1); |
| |
| for (int i = 0; i < interpolatedState.length; ++i) { |
| final double yDot0 = yDotK[0][i]; |
| final double yDot2 = yDotK[2][i]; |
| final double yDot3 = yDotK[3][i]; |
| final double yDot4 = yDotK[4][i]; |
| final double yDot5 = yDotK[5][i]; |
| interpolatedState[i] = |
| currentState[i] + b0 * yDot0 + b2 * yDot2 + b3 * yDot3 + b4 * yDot4 + b5 * yDot5; |
| interpolatedDerivatives[i] = |
| bDot0 * yDot0 + bDot2 * yDot2 + bDot3 * yDot3 + bDot4 * yDot4 + bDot5 * yDot5; |
| } |
| |
| } |
| |
| } |