SampledClockModel.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,
* 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.orekit.time;
import org.hipparchus.CalculusFieldElement;
import org.hipparchus.Field;
import org.orekit.utils.ImmutableTimeStampedCache;
import java.util.List;
import java.util.stream.Stream;
/** Offset clock model backed up by a sample.
* @author Luc Maisonobe
* @since 12.1
*/
public class SampledClockModel implements ClockModel {
/** sample. */
private final ImmutableTimeStampedCache<ClockOffset> sample;
/** Simple constructor.
* @param sample clock offsets sample
* @param nbInterpolationPoints number of points to use in interpolation
*/
public SampledClockModel(final List<ClockOffset> sample, final int nbInterpolationPoints) {
this.sample = new ImmutableTimeStampedCache<>(nbInterpolationPoints, sample);
}
/** Get the clock offsets cache.
* @return clock offsets cache
*/
public ImmutableTimeStampedCache<ClockOffset> getCache() {
return sample;
}
/** {@inheritDoc} */
@Override
public AbsoluteDate getValidityStart() {
return sample.getEarliest().getDate();
}
/** {@inheritDoc} */
@Override
public AbsoluteDate getValidityEnd() {
return sample.getLatest().getDate();
}
/** {@inheritDoc} */
@Override
public ClockOffset getOffset(final AbsoluteDate date) {
return new ClockOffsetHermiteInterpolator(sample.getMaxNeighborsSize()).
interpolate(date, sample.getNeighbors(date));
}
/** {@inheritDoc} */
@Override
public <T extends CalculusFieldElement<T>> FieldClockOffset<T> getOffset(final FieldAbsoluteDate<T> date) {
// convert the neighbors to field
final Field<T> field = date.getField();
final T zero = field.getZero();
final Stream<FieldClockOffset<T>> fieldSample =
sample.
getNeighbors(date.toAbsoluteDate()).
map(c -> {
final FieldAbsoluteDate<T> dateF = new FieldAbsoluteDate<>(field, c.getDate());
final T offsetF = zero.newInstance(c.getOffset());
final T rateF;
final T accelerationF;
if (Double.isNaN(c.getRate())) {
// no rate available
rateF = null;
accelerationF = null;
} else {
// rate available
rateF = zero.newInstance(c.getRate());
accelerationF = Double.isNaN(c.getAcceleration()) ?
null :
zero.newInstance(c.getAcceleration());
}
return new FieldClockOffset<>(dateF, offsetF, rateF, accelerationF);
});
// perform interpolation
final FieldClockOffsetHermiteInterpolator<T> interpolator =
new FieldClockOffsetHermiteInterpolator<>(sample.getMaxNeighborsSize());
return interpolator.interpolate(date, fieldSample);
}
}