| /* |
| * 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.sampling; |
| |
| import org.apache.commons.math4.legacy.core.RealFieldElement; |
| import org.apache.commons.math4.legacy.exception.MaxCountExceededException; |
| import org.apache.commons.math4.legacy.ode.FieldODEStateAndDerivative; |
| import org.apache.commons.math4.legacy.core.jdkmath.AccurateMath; |
| import org.apache.commons.numbers.core.Precision; |
| |
| /** |
| * This class wraps an object implementing {@link FieldFixedStepHandler} |
| * into a {@link FieldStepHandler}. |
| |
| * <p>This wrapper allows to use fixed step handlers with general |
| * integrators which cannot guaranty their integration steps will |
| * remain constant and therefore only accept general step |
| * handlers.</p> |
| * |
| * <p>The stepsize used is selected at construction time. The {@link |
| * FieldFixedStepHandler#handleStep handleStep} method of the underlying |
| * {@link FieldFixedStepHandler} object is called at normalized times. The |
| * normalized times can be influenced by the {@link StepNormalizerMode} and |
| * {@link StepNormalizerBounds}.</p> |
| * |
| * <p>There is no constraint on the integrator, it can use any time step |
| * it needs (time steps longer or shorter than the fixed time step and |
| * non-integer ratios are all allowed).</p> |
| * |
| * <table border="1" style="text-align: center" summary="Examples (step size = 0.5)"> |
| * <tr style="background-color: #CCCCFF"><td colspan=6 style="font-size: x-large">Examples (step size = 0.5)</td></tr> |
| * <tr style="background-color: #EEEEFF; font-size: large"><td>Start time</td><td>End time</td> |
| * <td>Direction</td><td>{@link StepNormalizerMode Mode}</td> |
| * <td>{@link StepNormalizerBounds Bounds}</td><td>Output</td></tr> |
| * <tr><td>0.3</td><td>3.1</td><td>forward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#NEITHER NEITHER}</td><td>0.8, 1.3, 1.8, 2.3, 2.8</td></tr> |
| * <tr><td>0.3</td><td>3.1</td><td>forward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#FIRST FIRST}</td><td>0.3, 0.8, 1.3, 1.8, 2.3, 2.8</td></tr> |
| * <tr><td>0.3</td><td>3.1</td><td>forward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#LAST LAST}</td><td>0.8, 1.3, 1.8, 2.3, 2.8, 3.1</td></tr> |
| * <tr><td>0.3</td><td>3.1</td><td>forward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#BOTH BOTH}</td><td>0.3, 0.8, 1.3, 1.8, 2.3, 2.8, 3.1</td></tr> |
| * <tr><td>0.3</td><td>3.1</td><td>forward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#NEITHER NEITHER}</td><td>0.5, 1.0, 1.5, 2.0, 2.5, 3.0</td></tr> |
| * <tr><td>0.3</td><td>3.1</td><td>forward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#FIRST FIRST}</td><td>0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0</td></tr> |
| * <tr><td>0.3</td><td>3.1</td><td>forward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#LAST LAST}</td><td>0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.1</td></tr> |
| * <tr><td>0.3</td><td>3.1</td><td>forward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#BOTH BOTH}</td><td>0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.1</td></tr> |
| * <tr><td>0.0</td><td>3.0</td><td>forward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#NEITHER NEITHER}</td><td>0.5, 1.0, 1.5, 2.0, 2.5, 3.0</td></tr> |
| * <tr><td>0.0</td><td>3.0</td><td>forward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#FIRST FIRST}</td><td>0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0</td></tr> |
| * <tr><td>0.0</td><td>3.0</td><td>forward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#LAST LAST}</td><td>0.5, 1.0, 1.5, 2.0, 2.5, 3.0</td></tr> |
| * <tr><td>0.0</td><td>3.0</td><td>forward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#BOTH BOTH}</td><td>0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0</td></tr> |
| * <tr><td>0.0</td><td>3.0</td><td>forward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#NEITHER NEITHER}</td><td>0.5, 1.0, 1.5, 2.0, 2.5, 3.0</td></tr> |
| * <tr><td>0.0</td><td>3.0</td><td>forward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#FIRST FIRST}</td><td>0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0</td></tr> |
| * <tr><td>0.0</td><td>3.0</td><td>forward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#LAST LAST}</td><td>0.5, 1.0, 1.5, 2.0, 2.5, 3.0</td></tr> |
| * <tr><td>0.0</td><td>3.0</td><td>forward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#BOTH BOTH}</td><td>0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0</td></tr> |
| * <tr><td>3.1</td><td>0.3</td><td>backward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#NEITHER NEITHER}</td><td>2.6, 2.1, 1.6, 1.1, 0.6</td></tr> |
| * <tr><td>3.1</td><td>0.3</td><td>backward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#FIRST FIRST}</td><td>3.1, 2.6, 2.1, 1.6, 1.1, 0.6</td></tr> |
| * <tr><td>3.1</td><td>0.3</td><td>backward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#LAST LAST}</td><td>2.6, 2.1, 1.6, 1.1, 0.6, 0.3</td></tr> |
| * <tr><td>3.1</td><td>0.3</td><td>backward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#BOTH BOTH}</td><td>3.1, 2.6, 2.1, 1.6, 1.1, 0.6, 0.3</td></tr> |
| * <tr><td>3.1</td><td>0.3</td><td>backward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#NEITHER NEITHER}</td><td>3.0, 2.5, 2.0, 1.5, 1.0, 0.5</td></tr> |
| * <tr><td>3.1</td><td>0.3</td><td>backward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#FIRST FIRST}</td><td>3.1, 3.0, 2.5, 2.0, 1.5, 1.0, 0.5</td></tr> |
| * <tr><td>3.1</td><td>0.3</td><td>backward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#LAST LAST}</td><td>3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.3</td></tr> |
| * <tr><td>3.1</td><td>0.3</td><td>backward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#BOTH BOTH}</td><td>3.1, 3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.3</td></tr> |
| * <tr><td>3.0</td><td>0.0</td><td>backward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#NEITHER NEITHER}</td><td>2.5, 2.0, 1.5, 1.0, 0.5, 0.0</td></tr> |
| * <tr><td>3.0</td><td>0.0</td><td>backward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#FIRST FIRST}</td><td>3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.0</td></tr> |
| * <tr><td>3.0</td><td>0.0</td><td>backward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#LAST LAST}</td><td>2.5, 2.0, 1.5, 1.0, 0.5, 0.0</td></tr> |
| * <tr><td>3.0</td><td>0.0</td><td>backward</td><td>{@link StepNormalizerMode#INCREMENT INCREMENT}</td><td>{@link StepNormalizerBounds#BOTH BOTH}</td><td>3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.0</td></tr> |
| * <tr><td>3.0</td><td>0.0</td><td>backward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#NEITHER NEITHER}</td><td>2.5, 2.0, 1.5, 1.0, 0.5, 0.0</td></tr> |
| * <tr><td>3.0</td><td>0.0</td><td>backward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#FIRST FIRST}</td><td>3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.0</td></tr> |
| * <tr><td>3.0</td><td>0.0</td><td>backward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#LAST LAST}</td><td>2.5, 2.0, 1.5, 1.0, 0.5, 0.0</td></tr> |
| * <tr><td>3.0</td><td>0.0</td><td>backward</td><td>{@link StepNormalizerMode#MULTIPLES MULTIPLES}</td><td>{@link StepNormalizerBounds#BOTH BOTH}</td><td>3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.0</td></tr> |
| * </table> |
| * |
| * @param <T> the type of the field elements |
| * @see FieldStepHandler |
| * @see FieldFixedStepHandler |
| * @see StepNormalizerMode |
| * @see StepNormalizerBounds |
| * @since 3.6 |
| */ |
| |
| public class FieldStepNormalizer<T extends RealFieldElement<T>> implements FieldStepHandler<T> { |
| |
| /** Fixed time step. */ |
| private double h; |
| |
| /** Underlying step handler. */ |
| private final FieldFixedStepHandler<T> handler; |
| |
| /** First step state. */ |
| private FieldODEStateAndDerivative<T> first; |
| |
| /** Last step step. */ |
| private FieldODEStateAndDerivative<T> last; |
| |
| /** Integration direction indicator. */ |
| private boolean forward; |
| |
| /** The step normalizer bounds settings to use. */ |
| private final StepNormalizerBounds bounds; |
| |
| /** The step normalizer mode to use. */ |
| private final StepNormalizerMode mode; |
| |
| /** Simple constructor. Uses {@link StepNormalizerMode#INCREMENT INCREMENT} |
| * mode, and {@link StepNormalizerBounds#FIRST FIRST} bounds setting, for |
| * backwards compatibility. |
| * @param h fixed time step (sign is not used) |
| * @param handler fixed time step handler to wrap |
| */ |
| public FieldStepNormalizer(final double h, final FieldFixedStepHandler<T> handler) { |
| this(h, handler, StepNormalizerMode.INCREMENT, |
| StepNormalizerBounds.FIRST); |
| } |
| |
| /** Simple constructor. Uses {@link StepNormalizerBounds#FIRST FIRST} |
| * bounds setting. |
| * @param h fixed time step (sign is not used) |
| * @param handler fixed time step handler to wrap |
| * @param mode step normalizer mode to use |
| * @since 3.0 |
| */ |
| public FieldStepNormalizer(final double h, final FieldFixedStepHandler<T> handler, |
| final StepNormalizerMode mode) { |
| this(h, handler, mode, StepNormalizerBounds.FIRST); |
| } |
| |
| /** Simple constructor. Uses {@link StepNormalizerMode#INCREMENT INCREMENT} |
| * mode. |
| * @param h fixed time step (sign is not used) |
| * @param handler fixed time step handler to wrap |
| * @param bounds step normalizer bounds setting to use |
| * @since 3.0 |
| */ |
| public FieldStepNormalizer(final double h, final FieldFixedStepHandler<T> handler, |
| final StepNormalizerBounds bounds) { |
| this(h, handler, StepNormalizerMode.INCREMENT, bounds); |
| } |
| |
| /** Simple constructor. |
| * @param h fixed time step (sign is not used) |
| * @param handler fixed time step handler to wrap |
| * @param mode step normalizer mode to use |
| * @param bounds step normalizer bounds setting to use |
| * @since 3.0 |
| */ |
| public FieldStepNormalizer(final double h, final FieldFixedStepHandler<T> handler, |
| final StepNormalizerMode mode, final StepNormalizerBounds bounds) { |
| this.h = AccurateMath.abs(h); |
| this.handler = handler; |
| this.mode = mode; |
| this.bounds = bounds; |
| first = null; |
| last = null; |
| forward = true; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public void init(final FieldODEStateAndDerivative<T> initialState, final T finalTime) { |
| |
| first = null; |
| last = null; |
| forward = true; |
| |
| // initialize the underlying handler |
| handler.init(initialState, finalTime); |
| |
| } |
| |
| /** |
| * Handle the last accepted step. |
| * @param interpolator interpolator for the last accepted step. For |
| * efficiency purposes, the various integrators reuse the same |
| * object on each call, so if the instance wants to keep it across |
| * all calls (for example to provide at the end of the integration a |
| * continuous model valid throughout the integration range), it |
| * should build a local copy using the clone method and store this |
| * copy. |
| * @param isLast true if the step is the last one |
| * @exception MaxCountExceededException if the interpolator throws one because |
| * the number of functions evaluations is exceeded |
| */ |
| @Override |
| public void handleStep(final FieldStepInterpolator<T> interpolator, final boolean isLast) |
| throws MaxCountExceededException { |
| // The first time, update the last state with the start information. |
| if (last == null) { |
| |
| first = interpolator.getPreviousState(); |
| last = first; |
| |
| // Take the integration direction into account. |
| forward = interpolator.isForward(); |
| if (!forward) { |
| h = -h; |
| } |
| } |
| |
| // Calculate next normalized step time. |
| T nextTime = (mode == StepNormalizerMode.INCREMENT) ? |
| last.getTime().add(h) : |
| last.getTime().getField().getZero().add((AccurateMath.floor(last.getTime().getReal() / h) + 1) * h); |
| if (mode == StepNormalizerMode.MULTIPLES && |
| Precision.equals(nextTime.getReal(), last.getTime().getReal(), 1)) { |
| nextTime = nextTime.add(h); |
| } |
| |
| // Process normalized steps as long as they are in the current step. |
| boolean nextInStep = isNextInStep(nextTime, interpolator); |
| while (nextInStep) { |
| // Output the stored previous step. |
| doNormalizedStep(false); |
| |
| // Store the next step as last step. |
| last = interpolator.getInterpolatedState(nextTime); |
| |
| // Move on to the next step. |
| nextTime = nextTime.add(h); |
| nextInStep = isNextInStep(nextTime, interpolator); |
| } |
| |
| if (isLast) { |
| // There will be no more steps. The stored one should be given to |
| // the handler. We may have to output one more step. Only the last |
| // one of those should be flagged as being the last. |
| final boolean addLast = bounds.lastIncluded() && |
| last.getTime().getReal() != interpolator.getCurrentState().getTime().getReal(); |
| doNormalizedStep(!addLast); |
| if (addLast) { |
| last = interpolator.getCurrentState(); |
| doNormalizedStep(true); |
| } |
| } |
| } |
| |
| /** |
| * Returns a value indicating whether the next normalized time is in the |
| * current step. |
| * @param nextTime the next normalized time |
| * @param interpolator interpolator for the last accepted step, to use to |
| * get the end time of the current step |
| * @return value indicating whether the next normalized time is in the |
| * current step |
| */ |
| private boolean isNextInStep(final T nextTime, final FieldStepInterpolator<T> interpolator) { |
| return forward ? |
| nextTime.getReal() <= interpolator.getCurrentState().getTime().getReal() : |
| nextTime.getReal() >= interpolator.getCurrentState().getTime().getReal(); |
| } |
| |
| /** |
| * Invokes the underlying step handler for the current normalized step. |
| * @param isLast true if the step is the last one |
| */ |
| private void doNormalizedStep(final boolean isLast) { |
| if (!bounds.firstIncluded() && first.getTime().getReal() == last.getTime().getReal()) { |
| return; |
| } |
| handler.handleStep(last, isLast); |
| } |
| |
| } |
