AbstractSolarActivityData.java
/* Copyright 2002-2023 CS GROUP
* 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.models.earth.atmosphere.data;
import org.hipparchus.exception.DummyLocalizable;
import org.orekit.data.DataProvidersManager;
import org.orekit.data.DataSource;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitMessages;
import org.orekit.models.earth.atmosphere.DTM2000InputParameters;
import org.orekit.models.earth.atmosphere.NRLMSISE00InputParameters;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.TimeScale;
import org.orekit.time.TimeStamped;
import org.orekit.utils.GenericTimeStampedCache;
import org.orekit.utils.ImmutableTimeStampedCache;
import org.orekit.utils.TimeStampedGenerator;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.function.Function;
import java.util.stream.Collectors;
/**
* Abstract class for solar activity data.
*
* @param <L> type of the line parameters
* @param <D> type of the solar activity data loader
*
* @author Vincent Cucchietti
* @since 12.0
*/
public abstract class AbstractSolarActivityData<L extends AbstractSolarActivityDataLoader.LineParameters, D extends AbstractSolarActivityDataLoader<L>>
implements DTM2000InputParameters, NRLMSISE00InputParameters {
/** Size of the list. */
protected static final int N_NEIGHBORS = 2;
/** Serializable UID. */
private static final long serialVersionUID = 8804818166227680449L;
/** Weather data thread safe cache. */
private final transient GenericTimeStampedCache<L> cache;
/** Supported names. */
private final String supportedNames;
/** UTC time scale. */
private final TimeScale utc;
/** First available date. */
private final AbsoluteDate firstDate;
/** Last available date. */
private final AbsoluteDate lastDate;
/**
* @param supportedNames regular expression for supported AGI/CSSI space weather files names
* @param loader data loader
* @param dataProvidersManager provides access to auxiliary data files.
* @param utc UTC time scale
* @param maxSlots maximum number of independent cached time slots in the
* {@link GenericTimeStampedCache time-stamped cache}
* @param maxSpan maximum duration span in seconds of one slot in the {@link GenericTimeStampedCache time-stamped cache}
* @param maxInterval time interval above which a new slot is created in the
* {@link GenericTimeStampedCache time-stamped cache}
* @param minimumStep overriding minimum step designed for non-homogeneous tabulated values. To be used for example when
* caching monthly tabulated values. May be null.
*/
protected AbstractSolarActivityData(final String supportedNames, final D loader,
final DataProvidersManager dataProvidersManager, final TimeScale utc,
final int maxSlots, final double maxSpan, final double maxInterval,
final double minimumStep) {
// Load data
dataProvidersManager.feed(supportedNames, loader);
// Create thread safe cache
this.cache = new GenericTimeStampedCache<>(N_NEIGHBORS, maxSlots, maxSpan, maxInterval,
new SolarActivityGenerator(loader.getDataSet()), minimumStep);
// Initialise fields
this.supportedNames = supportedNames;
this.utc = utc;
this.firstDate = loader.getMinDate();
this.lastDate = loader.getMaxDate();
}
/**
* Simple constructor.
*
* @param source source for the data
* @param loader data loader
* @param utc UTC time scale
* @param maxSlots maximum number of independent cached time slots in the
* {@link GenericTimeStampedCache time-stamped cache}
* @param maxSpan maximum duration span in seconds of one slot in the {@link GenericTimeStampedCache time-stamped cache}
* @param maxInterval time interval above which a new slot is created in the
* {@link GenericTimeStampedCache time-stamped cache}
* @param minimumStep overriding minimum step designed for non-homogeneous tabulated values. To be used for example when
* caching monthly tabulated values. May be null.
*
* @since 12.0
*/
public AbstractSolarActivityData(final DataSource source, final D loader, final TimeScale utc, final int maxSlots,
final double maxSpan, final double maxInterval, final double minimumStep) {
try {
// Load file
try (InputStream is = source.getOpener().openStreamOnce();
BufferedInputStream bis = new BufferedInputStream(is)) {
loader.loadData(bis, source.getName());
}
// Create thread safe cache
this.cache = new GenericTimeStampedCache<>(N_NEIGHBORS, maxSlots, maxSpan, maxInterval,
new SolarActivityGenerator(loader.getDataSet()), minimumStep);
// Initialise fields
this.supportedNames = source.getName();
this.utc = utc;
this.firstDate = loader.getMinDate();
this.lastDate = loader.getMaxDate();
}
catch (IOException | ParseException ioe) {
throw new OrekitException(ioe, new DummyLocalizable(ioe.getMessage()));
}
}
/**
* Performs a linear interpolation between two values The weights are computed from the time delta between previous date,
* current date, next date.
*
* @param date current date
* @param solarActivityToDoubleMapper mapping function taking solar activity as input and returning a double
*
* @return the value interpolated for the current date
*/
protected double getLinearInterpolation(final AbsoluteDate date, final Function<L, Double> solarActivityToDoubleMapper) {
// Create solar activity around current date
final LocalSolarActivity localSolarActivity = new LocalSolarActivity(date);
// Extract values
return getLinearInterpolation(localSolarActivity, solarActivityToDoubleMapper);
}
/**
* Performs a linear interpolation between two values The weights are computed from the time delta between previous date,
* current date, next date.
*
* @param localSolarActivity solar activity around current date
* @param solarActivityToDoubleMapper mapping function taking solar activity as input and returning a double
*
* @return the value interpolated for the current date
*/
protected double getLinearInterpolation(final LocalSolarActivity localSolarActivity,
final Function<L, Double> solarActivityToDoubleMapper) {
// Extract values
final L previousParameters = localSolarActivity.getPreviousParam();
final double previousValue = solarActivityToDoubleMapper.apply(previousParameters);
final L nextParameters = localSolarActivity.getNextParam();
final double nextValue = solarActivityToDoubleMapper.apply(nextParameters);
// Perform a linear interpolation
final AbsoluteDate previousDate = localSolarActivity.getPreviousParam().getDate();
final AbsoluteDate currentDate = localSolarActivity.getNextParam().getDate();
final double dt = currentDate.durationFrom(previousDate);
final AbsoluteDate date = localSolarActivity.getDate();
final double previousWeight = currentDate.durationFrom(date) / dt;
final double nextWeight = date.durationFrom(previousDate) / dt;
// Returns the data interpolated at the date
return previousValue * previousWeight + nextValue * nextWeight;
}
/**
* Get underlying cache.
*
* @return cache
*/
public GenericTimeStampedCache<L> getCache() {
return cache;
}
/**
* Get the supported names regular expression.
*
* @return the supported names.
*/
public String getSupportedNames() {
return supportedNames;
}
/**
* Get the UTC timescale.
*
* @return UTC timescale
*/
public TimeScale getUTC() {
return utc;
}
/** {@inheritDoc} */
@Override
public AbsoluteDate getMinDate() {
return firstDate;
}
/** {@inheritDoc} */
@Override
public AbsoluteDate getMaxDate() {
return lastDate;
}
/** Container for weather parameters around current date. Allows for thread safe use. */
protected class LocalSolarActivity implements TimeStamped {
/** Date. */
private final AbsoluteDate currentDate;
/** Previous parameters. */
private final L previousParam;
/** Next parameters. */
private final L nextParam;
/**
* Constructor.
*
* @param date current date
*/
public LocalSolarActivity(final AbsoluteDate date) {
// Asked date is before earliest available data
if (date.durationFrom(firstDate) < 0) {
throw new OrekitException(OrekitMessages.OUT_OF_RANGE_EPHEMERIDES_DATE_BEFORE, date, firstDate, lastDate,
firstDate.durationFrom(date));
}
// Asked date is after latest available data
if (date.durationFrom(lastDate) > 0) {
throw new OrekitException(OrekitMessages.OUT_OF_RANGE_EPHEMERIDES_DATE_AFTER, date, firstDate, lastDate,
date.durationFrom(lastDate));
}
final List<L> neighbours = cache.getNeighbors(date).collect(Collectors.toList());
this.currentDate = date;
this.previousParam = neighbours.get(0);
this.nextParam = neighbours.get(1);
}
/** @return current date */
public AbsoluteDate getDate() {
return currentDate;
}
/** @return previous parameters */
public L getPreviousParam() {
return previousParam;
}
/** @return next parameters */
public L getNextParam() {
return nextParam;
}
}
/** Generator used in the weather data cache. */
protected class SolarActivityGenerator implements TimeStampedGenerator<L> {
/**
* Default time step to shift the date.
* <p>
* It is used so that, in the case where the earliest date is exactly at noon, we do not get the following interval
* [previous day; current day] but rather the expected interval [current day; next day]
*/
private static final double STEP = 1;
/** Data set. */
private final ImmutableTimeStampedCache<L> data;
/**
* Constructor.
*
* @param dataSet weather data
*/
protected SolarActivityGenerator(final Collection<L> dataSet) {
this.data = new ImmutableTimeStampedCache<>(N_NEIGHBORS, dataSet);
}
/** {@inheritDoc} */
@Override
public List<L> generate(final AbsoluteDate existingDate, final AbsoluteDate date) {
// No prior data in the cache
if (existingDate == null) {
return data.getNeighbors(date).collect(Collectors.toList());
}
// Prior data in the cache, fill with data between date and existing date
if (date.isBefore(existingDate)) {
return generateDataFromEarliestToLatestDates(date, existingDate);
}
return generateDataFromEarliestToLatestDates(existingDate, date);
}
/**
* Generate a list of parameters between earliest and latest dates.
*
* @param earliest earliest date
* @param latest latest date
*
* @return list of parameters between earliest and latest dates
*/
public List<L> generateDataFromEarliestToLatestDates(final AbsoluteDate earliest, final AbsoluteDate latest) {
/* Gives first two parameters bracketing the earliest date
* A date shifted by step is used so that, in the case where the earliest date is exactly noon, we do not get the
* following interval [previous day; current day] but rather the expected interval [current day; next day] */
List<L> neighbours = data.getNeighbors(earliest.shiftedBy(STEP)).collect(Collectors.toList());
// Get next parameter until it brackets the latest date
AbsoluteDate latestNeighbourDate = neighbours.get(1).getDate();
final List<L> params = new ArrayList<>(neighbours);
while (latestNeighbourDate.isBefore(latest)) {
neighbours = data.getNeighbors(latestNeighbourDate.shiftedBy(STEP)).collect(Collectors.toList());
params.add(neighbours.get(1));
latestNeighbourDate = neighbours.get(1).getDate();
}
return params;
}
}
}