FieldClockOffsetHermiteInterpolator.java
/* Copyright 2002-2024 Thales Alenia Space
* Licensed to CS GROUP (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS 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,
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package org.orekit.time;
import org.hipparchus.CalculusFieldElement;
import org.hipparchus.analysis.interpolation.FieldHermiteInterpolator;
import org.hipparchus.analysis.interpolation.HermiteInterpolator;
import org.hipparchus.util.MathArrays;
import java.util.List;
/**bHermite interpolator of time stamped clock offsets.
* @param <T> type of the field elements
* @author Luc Maisonobe
* @see HermiteInterpolator
* @see TimeInterpolator
* @since 12.1
*/
public class FieldClockOffsetHermiteInterpolator<T extends CalculusFieldElement<T>>
extends AbstractFieldTimeInterpolator<FieldClockOffset<T>, T> {
/**
* Constructor with default extrapolation threshold value ({@code DEFAULT_EXTRAPOLATION_THRESHOLD_SEC} s).
* <p>
* As this implementation of interpolation is polynomial, it should be used only with small number of interpolation
* points (about 10-20 points) in order to avoid <a href="http://en.wikipedia.org/wiki/Runge%27s_phenomenon">Runge's
* phenomenon</a> and numerical problems (including NaN appearing).
* </p>
* <p>
* If the number of interpolation points or derivatives availability is not sufficient,
* the rate and acceleration of interpolated offset will be silently set to 0 (i.e.
* model will be constant or linear only).
* </p>
* @param interpolationPoints number of interpolation points
*/
public FieldClockOffsetHermiteInterpolator(final int interpolationPoints) {
this(interpolationPoints, DEFAULT_EXTRAPOLATION_THRESHOLD_SEC);
}
/**
* Constructor.
* <p>
* As this implementation of interpolation is polynomial, it should be used only with small number of interpolation
* points (about 10-20 points) in order to avoid <a href="http://en.wikipedia.org/wiki/Runge%27s_phenomenon">Runge's
* phenomenon</a> and numerical problems (including NaN appearing).
* </p>
* <p>
* If the number of interpolation points or derivatives availability is not sufficient,
* the rate and acceleration of interpolated offset will be silently set to 0 (i.e.
* model will be constant or linear only).
* </p>
* @param interpolationPoints number of interpolation points
* @param extrapolationThreshold extrapolation threshold beyond which the propagation will fail
*/
public FieldClockOffsetHermiteInterpolator(final int interpolationPoints, final double extrapolationThreshold) {
super(interpolationPoints, extrapolationThreshold);
}
/** {@inheritDoc} */
@Override
protected FieldClockOffset<T> interpolate(final InterpolationData interpolationData) {
final FieldHermiteInterpolator<T> interpolator = new FieldHermiteInterpolator<>();
// Fill interpolator with sample
final FieldAbsoluteDate<T> interpolationDate = interpolationData.getInterpolationDate();
final List<FieldClockOffset<T>> neighborList = interpolationData.getNeighborList();
for (FieldClockOffset<T> value : neighborList) {
final T deltaT = value.getDate().durationFrom(interpolationDate);
final T[] offset = MathArrays.buildArray(interpolationDate.getField(), 1);
offset[0] = value.getOffset();
if (value.getRate() == null || value.getRate().isNaN()) {
// no clock rate for this entry
interpolator.addSamplePoint(deltaT, offset);
} else {
// clock rate is available
final T[] rate = MathArrays.buildArray(interpolationDate.getField(), 1);
rate[0] = value.getRate();
if (value.getAcceleration() == null || value.getAcceleration().isNaN()) {
// no clock acceleration for this entry
interpolator.addSamplePoint(deltaT, offset, rate);
} else {
// clock acceleration is available
final T[] acceleration = MathArrays.buildArray(interpolationDate.getField(), 1);
acceleration[0] = value.getAcceleration();
interpolator.addSamplePoint(deltaT, offset, rate, acceleration);
}
}
}
final T[][] y = interpolator.derivatives(interpolationDate.getField().getZero(), 2);
return new FieldClockOffset<>(interpolationDate, y[0][0], y[1][0], y[2][0]);
}
}