JacobianPropagatorConverter.java
/* Copyright 2002-2020 CS GROUP
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* 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
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*
* 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.propagation.conversion;
import java.util.List;
import org.hipparchus.analysis.MultivariateVectorFunction;
import org.hipparchus.linear.ArrayRealVector;
import org.hipparchus.linear.MatrixUtils;
import org.hipparchus.linear.RealMatrix;
import org.hipparchus.linear.RealVector;
import org.hipparchus.ode.events.Action;
import org.hipparchus.optim.nonlinear.vector.leastsquares.MultivariateJacobianFunction;
import org.hipparchus.util.Pair;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitMessages;
import org.orekit.orbits.OrbitType;
import org.orekit.propagation.SpacecraftState;
import org.orekit.propagation.events.DateDetector;
import org.orekit.propagation.events.handlers.EventHandler;
import org.orekit.propagation.numerical.JacobiansMapper;
import org.orekit.propagation.numerical.NumericalPropagator;
import org.orekit.propagation.numerical.PartialDerivativesEquations;
import org.orekit.utils.PVCoordinates;
import org.orekit.utils.ParameterDriver;
import org.orekit.utils.ParameterDriversList;
/** Propagator converter using the real Jacobian.
* @author Pascal Parraud
* @since 6.0
*/
public class JacobianPropagatorConverter extends AbstractPropagatorConverter {
/** Numerical propagator builder. */
private final NumericalPropagatorBuilder builder;
/** Simple constructor.
* @param builder builder for adapted propagator, it <em>must</em>
* be configured to generate {@link OrbitType#CARTESIAN} states
* @param threshold absolute threshold for optimization algorithm
* @param maxIterations maximum number of iterations for fitting
*/
public JacobianPropagatorConverter(final NumericalPropagatorBuilder builder,
final double threshold,
final int maxIterations) {
super(builder, threshold, maxIterations);
if (builder.getOrbitType() != OrbitType.CARTESIAN) {
throw new OrekitException(OrekitMessages.ORBIT_TYPE_NOT_ALLOWED,
builder.getOrbitType(), OrbitType.CARTESIAN);
}
this.builder = builder;
}
/** {@inheritDoc} */
protected MultivariateVectorFunction getObjectiveFunction() {
return new MultivariateVectorFunction() {
/** {@inheritDoc} */
public double[] value(final double[] arg)
throws IllegalArgumentException, OrekitException {
final double[] value = new double[getTargetSize()];
final NumericalPropagator prop = builder.buildPropagator(arg);
final int stateSize = isOnlyPosition() ? 3 : 6;
final List<SpacecraftState> sample = getSample();
for (int i = 0; i < sample.size(); ++i) {
final int row = i * stateSize;
if (prop.getInitialState().getDate().equals(sample.get(i).getDate())) {
// use initial state
fillRows(value, row, prop.getInitialState());
} else {
// use a date detector to pick up states
prop.addEventDetector(new DateDetector(sample.get(i).getDate()).withHandler(new EventHandler<DateDetector>() {
/** {@inheritDoc} */
@Override
public Action eventOccurred(final SpacecraftState state, final DateDetector detector,
final boolean increasing) {
fillRows(value, row, state);
return row + stateSize >= getTargetSize() ? Action.STOP : Action.CONTINUE;
}
}));
}
}
prop.propagate(sample.get(sample.size() - 1).getDate().shiftedBy(10.0));
return value;
}
};
}
/** {@inheritDoc} */
protected MultivariateJacobianFunction getModel() {
return new MultivariateJacobianFunction() {
/** {@inheritDoc} */
public Pair<RealVector, RealMatrix> value(final RealVector point)
throws IllegalArgumentException, OrekitException {
final RealVector value = new ArrayRealVector(getTargetSize());
final RealMatrix jacobian = MatrixUtils.createRealMatrix(getTargetSize(), point.getDimension());
final NumericalPropagator prop = builder.buildPropagator(point.toArray());
final int stateSize = isOnlyPosition() ? 3 : 6;
final ParameterDriversList orbitalParameters = builder.getOrbitalParametersDrivers();
final PartialDerivativesEquations pde = new PartialDerivativesEquations("pde", prop);
final ParameterDriversList propagationParameters = pde.getSelectedParameters();
prop.setInitialState(pde.setInitialJacobians(prop.getInitialState()));
final JacobiansMapper mapper = pde.getMapper();
final List<SpacecraftState> sample = getSample();
for (int i = 0; i < sample.size(); ++i) {
final int row = i * stateSize;
if (prop.getInitialState().getDate().equals(sample.get(i).getDate())) {
// use initial state and Jacobians
fillRows(value, jacobian, row, prop.getInitialState(), stateSize,
orbitalParameters, propagationParameters, mapper);
} else {
// use a date detector to pick up state and Jacobians
prop.addEventDetector(new DateDetector(sample.get(i).getDate()).withHandler(new EventHandler<DateDetector>() {
/** {@inheritDoc} */
@Override
public Action eventOccurred(final SpacecraftState state, final DateDetector detector,
final boolean increasing) {
fillRows(value, jacobian, row, state, stateSize,
orbitalParameters, propagationParameters, mapper);
return row + stateSize >= getTargetSize() ? Action.STOP : Action.CONTINUE;
}
}));
}
}
prop.propagate(sample.get(sample.size() - 1).getDate().shiftedBy(10.0));
return new Pair<RealVector, RealMatrix>(value, jacobian);
}
};
}
/** Fill up a few value rows (either 6 or 3 depending on velocities used or not).
* @param value values array
* @param row first row index
* @param state spacecraft state
*/
private void fillRows(final double[] value, final int row, final SpacecraftState state) {
final PVCoordinates pv = state.getPVCoordinates(getFrame());
value[row ] = pv.getPosition().getX();
value[row + 1] = pv.getPosition().getY();
value[row + 2] = pv.getPosition().getZ();
if (!isOnlyPosition()) {
value[row + 3] = pv.getVelocity().getX();
value[row + 4] = pv.getVelocity().getY();
value[row + 5] = pv.getVelocity().getZ();
}
}
/** Fill up a few Jacobian rows (either 6 or 3 depending on velocities used or not).
* @param value values vector
* @param jacobian Jacobian matrix
* @param row first row index
* @param state spacecraft state
* @param stateSize state size
* @param orbitalParameters drivers for the orbital parameters
* @param propagationParameters drivers for the propagation model parameters
* @param mapper state mapper
*/
private void fillRows(final RealVector value, final RealMatrix jacobian, final int row,
final SpacecraftState state, final int stateSize,
final ParameterDriversList orbitalParameters,
final ParameterDriversList propagationParameters,
final JacobiansMapper mapper) {
// value part
final PVCoordinates pv = state.getPVCoordinates(getFrame());
value.setEntry(row, pv.getPosition().getX());
value.setEntry(row + 1, pv.getPosition().getY());
value.setEntry(row + 2, pv.getPosition().getZ());
if (!isOnlyPosition()) {
value.setEntry(row + 3, pv.getVelocity().getX());
value.setEntry(row + 4, pv.getVelocity().getY());
value.setEntry(row + 5, pv.getVelocity().getZ());
}
// Jacobian part
final double[][] dYdY0 = new double[JacobiansMapper.STATE_DIMENSION][JacobiansMapper.STATE_DIMENSION];
final double[][] dYdP = new double[JacobiansMapper.STATE_DIMENSION][mapper.getParameters()];
mapper.getStateJacobian(state, dYdY0);
mapper.getParametersJacobian(state, dYdP);
for (int k = 0; k < stateSize; k++) {
int index = 0;
for (int j = 0; j < orbitalParameters.getNbParams(); ++j) {
final ParameterDriver driver = orbitalParameters.getDrivers().get(j);
if (driver.isSelected()) {
jacobian.setEntry(row + k, index++, dYdY0[k][j] * driver.getScale());
}
}
for (int j = 0; j < propagationParameters.getNbParams(); ++j) {
final ParameterDriver driver = propagationParameters.getDrivers().get(j);
jacobian.setEntry(row + k, index++, dYdP[k][j] * driver.getScale());
}
}
}
}