| /* |
| * 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.math4.legacy.ode.nonstiff; |
| |
| import org.apache.commons.math4.legacy.core.Field; |
| import org.apache.commons.math4.legacy.core.RealFieldElement; |
| import org.apache.commons.math4.legacy.ode.FieldEquationsMapper; |
| import org.apache.commons.math4.legacy.ode.FieldODEStateAndDerivative; |
| |
| /** |
| * This class represents an interpolator over the last step during an |
| * ODE integration for the 5(4) Higham and Hall integrator. |
| * |
| * @see HighamHall54FieldIntegrator |
| * |
| * @param <T> the type of the field elements |
| * @since 3.6 |
| */ |
| |
| class HighamHall54FieldStepInterpolator<T extends RealFieldElement<T>> |
| extends RungeKuttaFieldStepInterpolator<T> { |
| |
| /** Simple constructor. |
| * @param field field to which the time and state vector elements belong |
| * @param forward integration direction indicator |
| * @param yDotK slopes at the intermediate points |
| * @param globalPreviousState start of the global step |
| * @param globalCurrentState end of the global step |
| * @param softPreviousState start of the restricted step |
| * @param softCurrentState end of the restricted step |
| * @param mapper equations mapper for the all equations |
| */ |
| HighamHall54FieldStepInterpolator(final Field<T> field, final boolean forward, |
| final T[][] yDotK, |
| final FieldODEStateAndDerivative<T> globalPreviousState, |
| final FieldODEStateAndDerivative<T> globalCurrentState, |
| final FieldODEStateAndDerivative<T> softPreviousState, |
| final FieldODEStateAndDerivative<T> softCurrentState, |
| final FieldEquationsMapper<T> mapper) { |
| super(field, forward, yDotK, |
| globalPreviousState, globalCurrentState, softPreviousState, softCurrentState, |
| mapper); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| protected HighamHall54FieldStepInterpolator<T> create(final Field<T> newField, final boolean newForward, final T[][] newYDotK, |
| final FieldODEStateAndDerivative<T> newGlobalPreviousState, |
| final FieldODEStateAndDerivative<T> newGlobalCurrentState, |
| final FieldODEStateAndDerivative<T> newSoftPreviousState, |
| final FieldODEStateAndDerivative<T> newSoftCurrentState, |
| final FieldEquationsMapper<T> newMapper) { |
| return new HighamHall54FieldStepInterpolator<>(newField, newForward, newYDotK, |
| newGlobalPreviousState, newGlobalCurrentState, |
| newSoftPreviousState, newSoftCurrentState, |
| newMapper); |
| } |
| |
| /** {@inheritDoc} */ |
| @SuppressWarnings("unchecked") |
| @Override |
| protected FieldODEStateAndDerivative<T> computeInterpolatedStateAndDerivatives(final FieldEquationsMapper<T> mapper, |
| final T time, final T theta, |
| final T thetaH, final T oneMinusThetaH) { |
| |
| final T bDot0 = theta.multiply(theta.multiply(theta.multiply( -10.0 ).add( 16.0 )).add(-15.0 / 2.0)).add(1); |
| final T bDot1 = time.getField().getZero(); |
| final T bDot2 = theta.multiply(theta.multiply(theta.multiply( 135.0 / 2.0).add(-729.0 / 8.0)).add(459.0 / 16.0)); |
| final T bDot3 = theta.multiply(theta.multiply(theta.multiply(-120.0 ).add( 152.0 )).add(-44.0 )); |
| final T bDot4 = theta.multiply(theta.multiply(theta.multiply( 125.0 / 2.0).add(-625.0 / 8.0)).add(375.0 / 16.0)); |
| final T bDot5 = theta.multiply( 5.0 / 8.0).multiply(theta.multiply(2).subtract(1)); |
| final T[] interpolatedState; |
| final T[] interpolatedDerivatives; |
| |
| if (getGlobalPreviousState() != null && theta.getReal() <= 0.5) { |
| final T b0 = thetaH.multiply(theta.multiply(theta.multiply(theta.multiply( -5.0 / 2.0).add( 16.0 / 3.0)).add(-15.0 / 4.0)).add(1)); |
| final T b1 = time.getField().getZero(); |
| final T b2 = thetaH.multiply(theta.multiply(theta.multiply(theta.multiply(135.0 / 8.0).add(-243.0 / 8.0)).add(459.0 / 32.0))); |
| final T b3 = thetaH.multiply(theta.multiply(theta.multiply(theta.multiply(-30.0 ).add( 152.0 / 3.0)).add(-22.0 ))); |
| final T b4 = thetaH.multiply(theta.multiply(theta.multiply(theta.multiply(125.0 / 8.0).add(-625.0 / 24.0)).add(375.0 / 32.0))); |
| final T b5 = thetaH.multiply(theta.multiply(theta.multiply( 5.0 / 12.0 ).add( -5.0 / 16.0))); |
| interpolatedState = previousStateLinearCombination(b0, b1, b2, b3, b4, b5); |
| interpolatedDerivatives = derivativeLinearCombination(bDot0, bDot1, bDot2, bDot3, bDot4, bDot5); |
| } else { |
| final T theta2 = theta.multiply(theta); |
| final T h = thetaH.divide(theta); |
| final T b0 = h.multiply( theta.multiply(theta.multiply(theta.multiply(theta.multiply(-5.0 / 2.0).add( 16.0 / 3.0)).add( -15.0 / 4.0)).add( 1.0 )).add( -1.0 / 12.0)); |
| final T b1 = time.getField().getZero(); |
| final T b2 = h.multiply(theta2.multiply(theta.multiply(theta.multiply( 135.0 / 8.0 ).add(-243.0 / 8.0)).add(459.0 / 32.0)).add( -27.0 / 32.0)); |
| final T b3 = h.multiply(theta2.multiply(theta.multiply(theta.multiply( -30.0 ).add( 152.0 / 3.0)).add(-22.0 )).add( 4.0 / 3.0)); |
| final T b4 = h.multiply(theta2.multiply(theta.multiply(theta.multiply( 125.0 / 8.0 ).add(-625.0 / 24.0)).add(375.0 / 32.0)).add(-125.0 / 96.0)); |
| final T b5 = h.multiply(theta2.multiply(theta.multiply( 5.0 / 12.0 ).add(-5.0 / 16.0)).add( -5.0 / 48.0)); |
| interpolatedState = currentStateLinearCombination(b0, b1, b2, b3, b4, b5); |
| interpolatedDerivatives = derivativeLinearCombination(bDot0, bDot1, bDot2, bDot3, bDot4, bDot5); |
| } |
| |
| return new FieldODEStateAndDerivative<>(time, interpolatedState, interpolatedDerivatives); |
| |
| } |
| |
| } |
