AbstractIntegratedPropagator.java

  1. /* Copyright 2002-2023 CS GROUP
  2.  * Licensed to CS GROUP (CS) under one or more
  3.  * contributor license agreements.  See the NOTICE file distributed with
  4.  * this work for additional information regarding copyright ownership.
  5.  * CS licenses this file to You under the Apache License, Version 2.0
  6.  * (the "License"); you may not use this file except in compliance with
  7.  * the License.  You may obtain a copy of the License at
  8.  *
  9.  *   http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */
  17. package org.orekit.propagation.integration;

  19. import java.util.ArrayList;
  20. import java.util.Arrays;
  21. import java.util.Collection;
  22. import java.util.Collections;
  23. import java.util.HashMap;
  24. import java.util.LinkedList;
  25. import java.util.List;
  26. import java.util.Map;
  27. import java.util.Queue;

  29. import org.hipparchus.analysis.UnivariateFunction;
  30. import org.hipparchus.analysis.solvers.BracketedUnivariateSolver;
  31. import org.hipparchus.analysis.solvers.BracketingNthOrderBrentSolver;
  32. import org.hipparchus.exception.MathRuntimeException;
  33. import org.hipparchus.ode.DenseOutputModel;
  34. import org.hipparchus.ode.ExpandableODE;
  35. import org.hipparchus.ode.ODEIntegrator;
  36. import org.hipparchus.ode.ODEState;
  37. import org.hipparchus.ode.ODEStateAndDerivative;
  38. import org.hipparchus.ode.OrdinaryDifferentialEquation;
  39. import org.hipparchus.ode.SecondaryODE;
  40. import org.hipparchus.ode.events.Action;
  41. import org.hipparchus.ode.events.AdaptableInterval;
  42. import org.hipparchus.ode.events.ODEEventDetector;
  43. import org.hipparchus.ode.events.ODEEventHandler;
  44. import org.hipparchus.ode.sampling.AbstractODEStateInterpolator;
  45. import org.hipparchus.ode.sampling.ODEStateInterpolator;
  46. import org.hipparchus.ode.sampling.ODEStepHandler;
  47. import org.hipparchus.util.Precision;
  48. import org.orekit.attitudes.AttitudeProvider;
  49. import org.orekit.errors.OrekitException;
  50. import org.orekit.errors.OrekitInternalError;
  51. import org.orekit.errors.OrekitMessages;
  52. import org.orekit.frames.Frame;
  53. import org.orekit.orbits.OrbitType;
  54. import org.orekit.orbits.PositionAngleType;
  55. import org.orekit.propagation.AbstractPropagator;
  56. import org.orekit.propagation.BoundedPropagator;
  57. import org.orekit.propagation.EphemerisGenerator;
  58. import org.orekit.propagation.PropagationType;
  59. import org.orekit.propagation.SpacecraftState;
  60. import org.orekit.propagation.events.EventDetector;
  61. import org.orekit.propagation.events.handlers.EventHandler;
  62. import org.orekit.propagation.sampling.OrekitStepHandler;
  63. import org.orekit.propagation.sampling.OrekitStepInterpolator;
  64. import org.orekit.time.AbsoluteDate;
  65. import org.orekit.utils.DoubleArrayDictionary;


  68. /** Common handling of {@link org.orekit.propagation.Propagator Propagator}
  69.  *  methods for both numerical and semi-analytical propagators.
  70.  *  @author Luc Maisonobe
  71.  */
  72. public abstract class AbstractIntegratedPropagator extends AbstractPropagator {

  74.     /** Internal name used for complete secondary state dimension.
  75.      * @since 11.1
  76.      */
  77.     private static final String SECONDARY_DIMENSION = "Orekit-secondary-dimension";

  79.     /** Event detectors not related to force models. */
  80.     private final List<EventDetector> detectors;

  82.     /** Step handlers dedicated to ephemeris generation. */
  83.     private final List<StoringStepHandler> ephemerisGenerators;

  85.     /** Integrator selected by the user for the orbital extrapolation process. */
  86.     private final ODEIntegrator integrator;

  88.     /** Offsets of secondary states managed by {@link AdditionalEquations}.
  89.      * @since 11.1
  90.      */
  91.     private final Map<String, Integer> secondaryOffsets;

  93.     /** Additional derivatives providers.
  94.      * @since 11.1
  95.      */
  96.     private List<AdditionalDerivativesProvider> additionalDerivativesProviders;

  98.     /** Map of secondary equation offset in main
  99.     /** Counter for differential equations calls. */
  100.     private int calls;

  102.     /** Mapper between raw double components and space flight dynamics objects. */
  103.     private StateMapper stateMapper;

  105.     /** Flag for resetting the state at end of propagation. */
  106.     private boolean resetAtEnd;

  108.     /** Type of orbit to output (mean or osculating) <br/>
  109.      * <p>
  110.      * This is used only in the case of semi-analytical propagators where there is a clear separation between
  111.      * mean and short periodic elements. It is ignored by the Numerical propagator.
  112.      * </p>
  113.      */
  114.     private PropagationType propagationType;

  116.     /** Build a new instance.
  117.      * @param integrator numerical integrator to use for propagation.
  118.      * @param propagationType type of orbit to output (mean or osculating).
  119.      */
  120.     protected AbstractIntegratedPropagator(final ODEIntegrator integrator, final PropagationType propagationType) {
  121.         detectors                      = new ArrayList<>();
  122.         ephemerisGenerators            = new ArrayList<>();
  123.         additionalDerivativesProviders = new ArrayList<>();
  124.         this.secondaryOffsets          = new HashMap<>();
  125.         this.integrator                = integrator;
  126.         this.propagationType           = propagationType;
  127.         this.resetAtEnd                = true;
  128.     }

  130.     /** Allow/disallow resetting the initial state at end of propagation.
  131.      * <p>
  132.      * By default, at the end of the propagation, the propagator resets the initial state
  133.      * to the final state, thus allowing a new propagation to be started from there without
  134.      * recomputing the part already performed. Calling this method with {@code resetAtEnd} set
  135.      * to false changes prevents such reset.
  136.      * </p>
  137.      * @param resetAtEnd if true, at end of each propagation, the {@link
  138.      * #getInitialState() initial state} will be reset to the final state of
  139.      * the propagation, otherwise the initial state will be preserved
  140.      * @since 9.0
  141.      */
  142.     public void setResetAtEnd(final boolean resetAtEnd) {
  143.         this.resetAtEnd = resetAtEnd;
  144.     }

  146.     /** Getter for the resetting flag regarding initial state.
  147.      * @return resetting flag
  148.      * @since 12.0
  149.      */
  150.     public boolean getResetAtEnd() {
  151.         return this.resetAtEnd;
  152.     }

  154.     /** Initialize the mapper. */
  155.     protected void initMapper() {
  156.         stateMapper = createMapper(null, Double.NaN, null, null, null, null);
  157.     }

  159.     /** Get the integrator's name.
  160.      * @return name of underlying integrator
  161.      * @since 12.0
  162.      */
  163.     public String getIntegratorName() {
  164.         return integrator.getName();
  165.     }

  167.     /**  {@inheritDoc} */
  168.     public void setAttitudeProvider(final AttitudeProvider attitudeProvider) {
  169.         super.setAttitudeProvider(attitudeProvider);
  170.         stateMapper = createMapper(stateMapper.getReferenceDate(), stateMapper.getMu(),
  171.                                    stateMapper.getOrbitType(), stateMapper.getPositionAngleType(),
  172.                                    attitudeProvider, stateMapper.getFrame());
  173.     }

  175.     /** Set propagation orbit type.
  176.      * @param orbitType orbit type to use for propagation, null for
  177.      * propagating using {@link org.orekit.utils.AbsolutePVCoordinates AbsolutePVCoordinates}
  178.      * rather than {@link org.orekit.orbits Orbit}
  179.      */
  180.     protected void setOrbitType(final OrbitType orbitType) {
  181.         stateMapper = createMapper(stateMapper.getReferenceDate(), stateMapper.getMu(),
  182.                                    orbitType, stateMapper.getPositionAngleType(),
  183.                                    stateMapper.getAttitudeProvider(), stateMapper.getFrame());
  184.     }

  186.     /** Get propagation parameter type.
  187.      * @return orbit type used for propagation, null for
  188.      * propagating using {@link org.orekit.utils.AbsolutePVCoordinates AbsolutePVCoordinates}
  189.      * rather than {@link org.orekit.orbits Orbit}
  190.      */
  191.     protected OrbitType getOrbitType() {
  192.         return stateMapper.getOrbitType();
  193.     }

  195.     /** Get the propagation type.
  196.      * @return propagation type.
  197.      * @since 11.1
  198.      */
  199.     public PropagationType getPropagationType() {
  200.         return propagationType;
  201.     }

  203.     /** Set position angle type.
  204.      * <p>
  205.      * The position parameter type is meaningful only if {@link
  206.      * #getOrbitType() propagation orbit type}
  207.      * support it. As an example, it is not meaningful for propagation
  208.      * in {@link OrbitType#CARTESIAN Cartesian} parameters.
  209.      * </p>
  210.      * @param positionAngleType angle type to use for propagation
  211.      */
  212.     protected void setPositionAngleType(final PositionAngleType positionAngleType) {
  213.         stateMapper = createMapper(stateMapper.getReferenceDate(), stateMapper.getMu(),
  214.                                    stateMapper.getOrbitType(), positionAngleType,
  215.                                    stateMapper.getAttitudeProvider(), stateMapper.getFrame());
  216.     }

  218.     /** Get propagation parameter type.
  219.      * @return angle type to use for propagation
  220.      */
  221.     protected PositionAngleType getPositionAngleType() {
  222.         return stateMapper.getPositionAngleType();
  223.     }

  225.     /** Set the central attraction coefficient μ.
  226.      * @param mu central attraction coefficient (m³/s²)
  227.      */
  228.     public void setMu(final double mu) {
  229.         stateMapper = createMapper(stateMapper.getReferenceDate(), mu,
  230.                                    stateMapper.getOrbitType(), stateMapper.getPositionAngleType(),
  231.                                    stateMapper.getAttitudeProvider(), stateMapper.getFrame());
  232.     }

  234.     /** Get the central attraction coefficient μ.
  235.      * @return mu central attraction coefficient (m³/s²)
  236.      * @see #setMu(double)
  237.      */
  238.     public double getMu() {
  239.         return stateMapper.getMu();
  240.     }

  242.     /** Get the number of calls to the differential equations computation method.
  243.      * <p>The number of calls is reset each time the {@link #propagate(AbsoluteDate)}
  244.      * method is called.</p>
  245.      * @return number of calls to the differential equations computation method
  246.      */
  247.     public int getCalls() {
  248.         return calls;
  249.     }

  251.     /** {@inheritDoc} */
  252.     @Override
  253.     public boolean isAdditionalStateManaged(final String name) {

  255.         // first look at already integrated states
  256.         if (super.isAdditionalStateManaged(name)) {
  257.             return true;
  258.         }

  260.         // then look at states we integrate ourselves
  261.         for (final AdditionalDerivativesProvider provider : additionalDerivativesProviders) {
  262.             if (provider.getName().equals(name)) {
  263.                 return true;
  264.             }
  265.         }

  267.         return false;
  268.     }

  270.     /** {@inheritDoc} */
  271.     @Override
  272.     public String[] getManagedAdditionalStates() {
  273.         final String[] alreadyIntegrated = super.getManagedAdditionalStates();
  274.         final String[] managed = new String[alreadyIntegrated.length + additionalDerivativesProviders.size()];
  275.         System.arraycopy(alreadyIntegrated, 0, managed, 0, alreadyIntegrated.length);
  276.         for (int i = 0; i < additionalDerivativesProviders.size(); ++i) {
  277.             managed[i + alreadyIntegrated.length] = additionalDerivativesProviders.get(i).getName();
  278.         }
  279.         return managed;
  280.     }

  282.     /** Add a provider for user-specified state derivatives to be integrated along with the orbit propagation.
  283.      * @param provider provider for additional derivatives
  284.      * @see #addAdditionalStateProvider(org.orekit.propagation.AdditionalStateProvider)
  285.      * @since 11.1
  286.      */
  287.     public void addAdditionalDerivativesProvider(final AdditionalDerivativesProvider provider) {

  289.         // check if the name is already used
  290.         if (isAdditionalStateManaged(provider.getName())) {
  291.             // these derivatives are already registered, complain
  292.             throw new OrekitException(OrekitMessages.ADDITIONAL_STATE_NAME_ALREADY_IN_USE,
  293.                                       provider.getName());
  294.         }

  296.         // this is really a new set of derivatives, add it
  297.         additionalDerivativesProviders.add(provider);

  299.         secondaryOffsets.clear();

  301.     }

  303.     /** Get an unmodifiable list of providers for additional derivatives.
  304.      * @return providers for the additional derivatives
  305.      * @since 11.1
  306.      */
  307.     public List<AdditionalDerivativesProvider> getAdditionalDerivativesProviders() {
  308.         return Collections.unmodifiableList(additionalDerivativesProviders);
  309.     }

  311.     /** {@inheritDoc} */
  312.     public void addEventDetector(final EventDetector detector) {
  313.         detectors.add(detector);
  314.     }

  316.     /** {@inheritDoc} */
  317.     public Collection<EventDetector> getEventsDetectors() {
  318.         return Collections.unmodifiableCollection(detectors);
  319.     }

  321.     /** {@inheritDoc} */
  322.     public void clearEventsDetectors() {
  323.         detectors.clear();
  324.     }

  326.     /** Set up all user defined event detectors.
  327.      */
  328.     protected void setUpUserEventDetectors() {
  329.         for (final EventDetector detector : detectors) {
  330.             setUpEventDetector(integrator, detector);
  331.         }
  332.     }

  334.     /** Wrap an Orekit event detector and register it to the integrator.
  335.      * @param integ integrator into which event detector should be registered
  336.      * @param detector event detector to wrap
  337.      */
  338.     protected void setUpEventDetector(final ODEIntegrator integ, final EventDetector detector) {
  339.         integ.addEventDetector(new AdaptedEventDetector(detector));
  340.     }

  342.     /** {@inheritDoc} */
  343.     @Override
  344.     public EphemerisGenerator getEphemerisGenerator() {
  345.         final StoringStepHandler storingHandler = new StoringStepHandler();
  346.         ephemerisGenerators.add(storingHandler);
  347.         return storingHandler;
  348.     }

  350.     /** Create a mapper between raw double components and spacecraft state.
  351.     /** Simple constructor.
  352.      * <p>
  353.      * The position parameter type is meaningful only if {@link
  354.      * #getOrbitType() propagation orbit type}
  355.      * support it. As an example, it is not meaningful for propagation
  356.      * in {@link OrbitType#CARTESIAN Cartesian} parameters.
  357.      * </p>
  358.      * @param referenceDate reference date
  359.      * @param mu central attraction coefficient (m³/s²)
  360.      * @param orbitType orbit type to use for mapping
  361.      * @param positionAngleType angle type to use for propagation
  362.      * @param attitudeProvider attitude provider
  363.      * @param frame inertial frame
  364.      * @return new mapper
  365.      */
  366.     protected abstract StateMapper createMapper(AbsoluteDate referenceDate, double mu,
  367.                                                 OrbitType orbitType, PositionAngleType positionAngleType,
  368.                                                 AttitudeProvider attitudeProvider, Frame frame);

  370.     /** Get the differential equations to integrate (for main state only).
  371.      * @param integ numerical integrator to use for propagation.
  372.      * @return differential equations for main state
  373.      */
  374.     protected abstract MainStateEquations getMainStateEquations(ODEIntegrator integ);

  376.     /** {@inheritDoc} */
  377.     public SpacecraftState propagate(final AbsoluteDate target) {
  378.         if (getStartDate() == null) {
  379.             if (getInitialState() == null) {
  380.                 throw new OrekitException(OrekitMessages.INITIAL_STATE_NOT_SPECIFIED_FOR_ORBIT_PROPAGATION);
  381.             }
  382.             setStartDate(getInitialState().getDate());
  383.         }
  384.         return propagate(getStartDate(), target);
  385.     }

  387.     /** {@inheritDoc} */
  388.     public SpacecraftState propagate(final AbsoluteDate tStart, final AbsoluteDate tEnd) {

  390.         if (getInitialState() == null) {
  391.             throw new OrekitException(OrekitMessages.INITIAL_STATE_NOT_SPECIFIED_FOR_ORBIT_PROPAGATION);
  392.         }

  394.         // make sure the integrator will be reset properly even if we change its events handlers and step handlers
  395.         try (IntegratorResetter resetter = new IntegratorResetter(integrator)) {

  397.             // prepare handling of STM and Jacobian matrices
  398.             setUpStmAndJacobianGenerators();

  400.             // Initialize additional states
  401.             initializeAdditionalStates(tEnd);

  403.             if (!tStart.equals(getInitialState().getDate())) {
  404.                 // if propagation start date is not initial date,
  405.                 // propagate from initial to start date without event detection
  406.                 try (IntegratorResetter startResetter = new IntegratorResetter(integrator)) {
  407.                     integrateDynamics(tStart);
  408.                 }
  409.             }

  411.             // set up events added by user
  412.             setUpUserEventDetectors();

  414.             // set up step handlers
  415.             for (final OrekitStepHandler handler : getMultiplexer().getHandlers()) {
  416.                 integrator.addStepHandler(new AdaptedStepHandler(handler));
  417.             }
  418.             for (final StoringStepHandler generator : ephemerisGenerators) {
  419.                 generator.setEndDate(tEnd);
  420.                 integrator.addStepHandler(generator);
  421.             }

  423.             // propagate from start date to end date with event detection
  424.             final SpacecraftState finalState = integrateDynamics(tEnd);

  426.             return finalState;

  428.         }

  430.     }

  432.     /** Set up State Transition Matrix and Jacobian matrix handling.
  433.      * @since 11.1
  434.      */
  435.     protected void setUpStmAndJacobianGenerators() {
  436.         // nothing to do by default
  437.     }

  439.     /** Propagation with or without event detection.
  440.      * @param tEnd target date to which orbit should be propagated
  441.      * @return state at end of propagation
  442.      */
  443.     private SpacecraftState integrateDynamics(final AbsoluteDate tEnd) {
  444.         try {

  446.             initializePropagation();

  448.             if (getInitialState().getDate().equals(tEnd)) {
  449.                 // don't extrapolate
  450.                 return getInitialState();
  451.             }

  453.             // space dynamics view
  454.             stateMapper = createMapper(getInitialState().getDate(), stateMapper.getMu(),
  455.                                        stateMapper.getOrbitType(), stateMapper.getPositionAngleType(),
  456.                                        stateMapper.getAttitudeProvider(), getInitialState().getFrame());


  459.             if (Double.isNaN(getMu())) {
  460.                 setMu(getInitialState().getMu());
  461.             }

  463.             if (getInitialState().getMass() <= 0.0) {
  464.                 throw new OrekitException(OrekitMessages.NOT_POSITIVE_SPACECRAFT_MASS,
  465.                                           getInitialState().getMass());
  466.             }

  468.             // convert space flight dynamics API to math API
  469.             final SpacecraftState initialIntegrationState = getInitialIntegrationState();
  470.             final ODEState mathInitialState = createInitialState(initialIntegrationState);
  471.             final ExpandableODE mathODE = createODE(integrator);

  473.             // mathematical integration
  474.             final ODEStateAndDerivative mathFinalState;
  475.             beforeIntegration(initialIntegrationState, tEnd);
  476.             mathFinalState = integrator.integrate(mathODE, mathInitialState,
  477.                                                   tEnd.durationFrom(getInitialState().getDate()));
  478.             afterIntegration();

  480.             // get final state
  481.             SpacecraftState finalState =
  482.                             stateMapper.mapArrayToState(stateMapper.mapDoubleToDate(mathFinalState.getTime(),
  483.                                                                                     tEnd),
  484.                                                         mathFinalState.getPrimaryState(),
  485.                                                         mathFinalState.getPrimaryDerivative(),
  486.                                                         propagationType);

  488.             if (!additionalDerivativesProviders.isEmpty()) {
  489.                 final double[] secondary            = mathFinalState.getSecondaryState(1);
  490.                 final double[] secondaryDerivatives = mathFinalState.getSecondaryDerivative(1);
  491.                 for (AdditionalDerivativesProvider provider : additionalDerivativesProviders) {
  492.                     final String   name        = provider.getName();
  493.                     final int      offset      = secondaryOffsets.get(name);
  494.                     final int      dimension   = provider.getDimension();
  495.                     finalState = finalState.
  496.                                  addAdditionalState(name, Arrays.copyOfRange(secondary, offset, offset + dimension)).
  497.                                  addAdditionalStateDerivative(name, Arrays.copyOfRange(secondaryDerivatives, offset, offset + dimension));
  498.                 }
  499.             }
  500.             finalState = updateAdditionalStates(finalState);

  502.             if (resetAtEnd) {
  503.                 resetInitialState(finalState);
  504.                 setStartDate(finalState.getDate());
  505.             }

  507.             return finalState;

  509.         } catch (MathRuntimeException mre) {
  510.             throw OrekitException.unwrap(mre);
  511.         }
  512.     }

  514.     /** Get the initial state for integration.
  515.      * @return initial state for integration
  516.      */
  517.     protected SpacecraftState getInitialIntegrationState() {
  518.         return getInitialState();
  519.     }

  521.     /** Create an initial state.
  522.      * @param initialState initial state in flight dynamics world
  523.      * @return initial state in mathematics world
  524.      */
  525.     private ODEState createInitialState(final SpacecraftState initialState) {

  527.         // retrieve initial state
  528.         final double[] primary = new double[getBasicDimension()];
  529.         stateMapper.mapStateToArray(initialState, primary, null);

  531.         if (secondaryOffsets.isEmpty()) {
  532.             // compute dimension of the secondary state
  533.             int offset = 0;
  534.             for (final AdditionalDerivativesProvider provider : additionalDerivativesProviders) {
  535.                 secondaryOffsets.put(provider.getName(), offset);
  536.                 offset += provider.getDimension();
  537.             }
  538.             secondaryOffsets.put(SECONDARY_DIMENSION, offset);
  539.         }

  541.         return new ODEState(0.0, primary, secondary(initialState));

  543.     }

  545.     /** Create secondary state.
  546.      * @param state spacecraft state
  547.      * @return secondary state
  548.      * @since 11.1
  549.      */
  550.     private double[][] secondary(final SpacecraftState state) {

  552.         if (secondaryOffsets.isEmpty()) {
  553.             return null;
  554.         }

  556.         final double[][] secondary = new double[1][secondaryOffsets.get(SECONDARY_DIMENSION)];
  557.         for (final AdditionalDerivativesProvider provider : additionalDerivativesProviders) {
  558.             final String   name       = provider.getName();
  559.             final int      offset     = secondaryOffsets.get(name);
  560.             final double[] additional = state.getAdditionalState(name);
  561.             System.arraycopy(additional, 0, secondary[0], offset, additional.length);
  562.         }

  564.         return secondary;

  566.     }

  568.     /** Create secondary state derivative.
  569.      * @param state spacecraft state
  570.      * @return secondary state derivative
  571.      * @since 11.1
  572.      */
  573.     private double[][] secondaryDerivative(final SpacecraftState state) {

  575.         if (secondaryOffsets.isEmpty()) {
  576.             return null;
  577.         }

  579.         final double[][] secondaryDerivative = new double[1][secondaryOffsets.get(SECONDARY_DIMENSION)];
  580.         for (final AdditionalDerivativesProvider provider : additionalDerivativesProviders) {
  581.             final String   name       = provider.getName();
  582.             final int      offset     = secondaryOffsets.get(name);
  583.             final double[] additionalDerivative = state.getAdditionalStateDerivative(name);
  584.             System.arraycopy(additionalDerivative, 0, secondaryDerivative[0], offset, additionalDerivative.length);
  585.         }

  587.         return secondaryDerivative;

  589.     }

  591.     /** Create an ODE with all equations.
  592.      * @param integ numerical integrator to use for propagation.
  593.      * @return a new ode
  594.      */
  595.     private ExpandableODE createODE(final ODEIntegrator integ) {

  597.         final ExpandableODE ode =
  598.                 new ExpandableODE(new ConvertedMainStateEquations(getMainStateEquations(integ)));

  600.         // secondary part of the ODE
  601.         if (!additionalDerivativesProviders.isEmpty()) {
  602.             ode.addSecondaryEquations(new ConvertedSecondaryStateEquations());
  603.         }

  605.         return ode;

  607.     }

  609.     /** Method called just before integration.
  610.      * <p>
  611.      * The default implementation does nothing, it may be specialized in subclasses.
  612.      * </p>
  613.      * @param initialState initial state
  614.      * @param tEnd target date at which state should be propagated
  615.      */
  616.     protected void beforeIntegration(final SpacecraftState initialState,
  617.                                      final AbsoluteDate tEnd) {
  618.         // do nothing by default
  619.     }

  621.     /** Method called just after integration.
  622.      * <p>
  623.      * The default implementation does nothing, it may be specialized in subclasses.
  624.      * </p>
  625.      */
  626.     protected void afterIntegration() {
  627.         // do nothing by default
  628.     }

  630.     /** Get state vector dimension without additional parameters.
  631.      * @return state vector dimension without additional parameters.
  632.      */
  633.     public int getBasicDimension() {
  634.         return 7;
  635.     }

  637.     /** Get the integrator used by the propagator.
  638.      * @return the integrator.
  639.      */
  640.     protected ODEIntegrator getIntegrator() {
  641.         return integrator;
  642.     }

  644.     /** Convert a state from mathematical world to space flight dynamics world.
  645.      * @param os mathematical state
  646.      * @return space flight dynamics state
  647.      */
  648.     private SpacecraftState convert(final ODEStateAndDerivative os) {

  650.         SpacecraftState s = stateMapper.mapArrayToState(os.getTime(),
  651.                                                         os.getPrimaryState(),
  652.                                                         os.getPrimaryDerivative(),
  653.                                                         propagationType);
  654.         if (os.getNumberOfSecondaryStates() > 0) {
  655.             final double[] secondary           = os.getSecondaryState(1);
  656.             final double[] secondaryDerivative = os.getSecondaryDerivative(1);
  657.             for (final AdditionalDerivativesProvider provider : additionalDerivativesProviders) {
  658.                 final String name      = provider.getName();
  659.                 final int    offset    = secondaryOffsets.get(name);
  660.                 final int    dimension = provider.getDimension();
  661.                 s = s.addAdditionalState(name, Arrays.copyOfRange(secondary, offset, offset + dimension));
  662.                 s = s.addAdditionalStateDerivative(name, Arrays.copyOfRange(secondaryDerivative, offset, offset + dimension));
  663.             }
  664.         }
  665.         s = updateAdditionalStates(s);

  667.         return s;

  669.     }

  671.     /** Convert a state from space flight dynamics world to mathematical world.
  672.      * @param state space flight dynamics state
  673.      * @return mathematical state
  674.      */
  675.     private ODEStateAndDerivative convert(final SpacecraftState state) {

  677.         // retrieve initial state
  678.         final double[] primary    = new double[getBasicDimension()];
  679.         final double[] primaryDot = new double[getBasicDimension()];
  680.         stateMapper.mapStateToArray(state, primary, primaryDot);

  682.         // secondary part of the ODE
  683.         final double[][] secondary           = secondary(state);
  684.         final double[][] secondaryDerivative = secondaryDerivative(state);

  686.         return new ODEStateAndDerivative(stateMapper.mapDateToDouble(state.getDate()),
  687.                                          primary, primaryDot,
  688.                                          secondary, secondaryDerivative);

  690.     }

  692.     /** Differential equations for the main state (orbit, attitude and mass). */
  693.     public interface MainStateEquations {

  695.         /**
  696.          * Initialize the equations at the start of propagation. This method will be
  697.          * called before any calls to {@link #computeDerivatives(SpacecraftState)}.
  698.          *
  699.          * <p> The default implementation of this method does nothing.
  700.          *
  701.          * @param initialState initial state information at the start of propagation.
  702.          * @param target       date of propagation. Not equal to {@code
  703.          *                     initialState.getDate()}.
  704.          */
  705.         default void init(final SpacecraftState initialState, final AbsoluteDate target) {
  706.         }

  708.         /** Compute differential equations for main state.
  709.          * @param state current state
  710.          * @return derivatives of main state
  711.          */
  712.         double[] computeDerivatives(SpacecraftState state);

  714.     }

  716.     /** Differential equations for the main state (orbit, attitude and mass), with converted API. */
  717.     private class ConvertedMainStateEquations implements OrdinaryDifferentialEquation {

  719.         /** Main state equations. */
  720.         private final MainStateEquations main;

  722.         /** Simple constructor.
  723.          * @param main main state equations
  724.          */
  725.         ConvertedMainStateEquations(final MainStateEquations main) {
  726.             this.main = main;
  727.             calls = 0;
  728.         }

  730.         /** {@inheritDoc} */
  731.         public int getDimension() {
  732.             return getBasicDimension();
  733.         }

  735.         @Override
  736.         public void init(final double t0, final double[] y0, final double finalTime) {
  737.             // update space dynamics view
  738.             SpacecraftState initialState = stateMapper.mapArrayToState(t0, y0, null, PropagationType.MEAN);
  739.             initialState = updateAdditionalStates(initialState);
  740.             final AbsoluteDate target = stateMapper.mapDoubleToDate(finalTime);
  741.             main.init(initialState, target);
  742.         }

  744.         /** {@inheritDoc} */
  745.         public double[] computeDerivatives(final double t, final double[] y) {

  747.             // increment calls counter
  748.             ++calls;

  750.             // update space dynamics view
  751.             SpacecraftState currentState = stateMapper.mapArrayToState(t, y, null, PropagationType.MEAN);

  753.             currentState = updateAdditionalStates(currentState);
  754.             // compute main state differentials
  755.             return main.computeDerivatives(currentState);

  757.         }

  759.     }

  761.     /** Differential equations for the secondary state (Jacobians, user variables ...), with converted API. */
  762.     private class ConvertedSecondaryStateEquations implements SecondaryODE {

  764.         /** Dimension of the combined additional states. */
  765.         private final int combinedDimension;

  767.         /** Simple constructor.
  768.           */
  769.         ConvertedSecondaryStateEquations() {
  770.             this.combinedDimension = secondaryOffsets.get(SECONDARY_DIMENSION);
  771.         }

  773.         /** {@inheritDoc} */
  774.         @Override
  775.         public int getDimension() {
  776.             return combinedDimension;
  777.         }

  779.         /** {@inheritDoc} */
  780.         @Override
  781.         public void init(final double t0, final double[] primary0,
  782.                          final double[] secondary0, final double finalTime) {
  783.             // update space dynamics view
  784.             final SpacecraftState initialState = convert(t0, primary0, null, secondary0);

  786.             final AbsoluteDate target = stateMapper.mapDoubleToDate(finalTime);
  787.             for (final AdditionalDerivativesProvider provider : additionalDerivativesProviders) {
  788.                 provider.init(initialState, target);
  789.             }

  791.         }

  793.         /** {@inheritDoc} */
  794.         @Override
  795.         public double[] computeDerivatives(final double t, final double[] primary,
  796.                                            final double[] primaryDot, final double[] secondary) {

  798.             // update space dynamics view
  799.             // the integrable generators generate method will be called here,
  800.             // according to the generators yield order
  801.             SpacecraftState updated = convert(t, primary, primaryDot, secondary);

  803.             // set up queue for equations
  804.             final Queue<AdditionalDerivativesProvider> pending = new LinkedList<>(additionalDerivativesProviders);

  806.             // gather the derivatives from all additional equations, taking care of dependencies
  807.             final double[] secondaryDot = new double[combinedDimension];
  808.             int yieldCount = 0;
  809.             while (!pending.isEmpty()) {
  810.                 final AdditionalDerivativesProvider provider = pending.remove();
  811.                 if (provider.yields(updated)) {
  812.                     // this provider has to wait for another one,
  813.                     // we put it again in the pending queue
  814.                     pending.add(provider);
  815.                     if (++yieldCount >= pending.size()) {
  816.                         // all pending providers yielded!, they probably need data not yet initialized
  817.                         // we let the propagation proceed, if these data are really needed right now
  818.                         // an appropriate exception will be triggered when caller tries to access them
  819.                         break;
  820.                     }
  821.                 } else {
  822.                     // we can use these equations right now
  823.                     final String              name           = provider.getName();
  824.                     final int                 offset         = secondaryOffsets.get(name);
  825.                     final int                 dimension      = provider.getDimension();
  826.                     final CombinedDerivatives derivatives    = provider.combinedDerivatives(updated);
  827.                     final double[]            additionalPart = derivatives.getAdditionalDerivatives();
  828.                     final double[]            mainPart       = derivatives.getMainStateDerivativesIncrements();
  829.                     System.arraycopy(additionalPart, 0, secondaryDot, offset, dimension);
  830.                     updated = updated.addAdditionalStateDerivative(name, additionalPart);
  831.                     if (mainPart != null) {
  832.                         // this equation does change the main state derivatives
  833.                         for (int i = 0; i < mainPart.length; ++i) {
  834.                             primaryDot[i] += mainPart[i];
  835.                         }
  836.                     }
  837.                     yieldCount = 0;
  838.                 }
  839.             }

  841.             return secondaryDot;

  843.         }

  845.         /** Convert mathematical view to space view.
  846.          * @param t current value of the independent <I>time</I> variable
  847.          * @param primary array containing the current value of the primary state vector
  848.          * @param primaryDot array containing the derivative of the primary state vector
  849.          * @param secondary array containing the current value of the secondary state vector
  850.          * @return space view of the state
  851.          */
  852.         private SpacecraftState convert(final double t, final double[] primary,
  853.                                         final double[] primaryDot, final double[] secondary) {

  855.             SpacecraftState initialState = stateMapper.mapArrayToState(t, primary, primaryDot, PropagationType.MEAN);

  857.             for (final AdditionalDerivativesProvider provider : additionalDerivativesProviders) {
  858.                 final String name      = provider.getName();
  859.                 final int    offset    = secondaryOffsets.get(name);
  860.                 final int    dimension = provider.getDimension();
  861.                 initialState = initialState.addAdditionalState(name, Arrays.copyOfRange(secondary, offset, offset + dimension));
  862.             }

  864.             return updateAdditionalStates(initialState);

  866.         }

  868.     }

  870.     /** Adapt an {@link org.orekit.propagation.events.EventDetector}
  871.      * to Hipparchus {@link org.hipparchus.ode.events.ODEEventDetector} interface.
  872.      * @author Fabien Maussion
  873.      */
  874.     private class AdaptedEventDetector implements ODEEventDetector {

  876.         /** Underlying event detector. */
  877.         private final EventDetector detector;

  879.         /** Underlying event handler.
  880.          * @since 12.0
  881.          */
  882.         private final EventHandler handler;

  884.         /** Time of the previous call to g. */
  885.         private double lastT;

  887.         /** Value from the previous call to g. */
  888.         private double lastG;

  890.         /** Build a wrapped event detector.
  891.          * @param detector event detector to wrap
  892.         */
  893.         AdaptedEventDetector(final EventDetector detector) {
  894.             this.detector = detector;
  895.             this.handler  = detector.getHandler();
  896.             this.lastT    = Double.NaN;
  897.             this.lastG    = Double.NaN;
  898.         }

  900.         /** {@inheritDoc} */
  901.         @Override
  902.         public AdaptableInterval getMaxCheckInterval() {
  903.             return s -> detector.getMaxCheckInterval().currentInterval(convert(s));
  904.         }

  906.         /** {@inheritDoc} */
  907.         @Override
  908.         public int getMaxIterationCount() {
  909.             return detector.getMaxIterationCount();
  910.         }

  912.         /** {@inheritDoc} */
  913.         @Override
  914.         public BracketedUnivariateSolver<UnivariateFunction> getSolver() {
  915.             return new BracketingNthOrderBrentSolver(0, detector.getThreshold(), 0, 5);
  916.         }

  918.         /** {@inheritDoc} */
  919.         public void init(final ODEStateAndDerivative s0, final double t) {
  920.             detector.init(convert(s0), stateMapper.mapDoubleToDate(t));
  921.             this.lastT = Double.NaN;
  922.             this.lastG = Double.NaN;
  923.         }

  925.         /** {@inheritDoc} */
  926.         public double g(final ODEStateAndDerivative s) {
  927.             if (!Precision.equals(lastT, s.getTime(), 0)) {
  928.                 lastT = s.getTime();
  929.                 lastG = detector.g(convert(s));
  930.             }
  931.             return lastG;
  932.         }

  934.         /** {@inheritDoc} */
  935.         public ODEEventHandler getHandler() {

  937.             return new ODEEventHandler() {

  939.                 /** {@inheritDoc} */
  940.                 public Action eventOccurred(final ODEStateAndDerivative s, final ODEEventDetector d, final boolean increasing) {
  941.                     return handler.eventOccurred(convert(s), detector, increasing);
  942.                 }

  944.                 /** {@inheritDoc} */
  945.                 public ODEState resetState(final ODEEventDetector d, final ODEStateAndDerivative s) {

  947.                     final SpacecraftState oldState = convert(s);
  948.                     final SpacecraftState newState = handler.resetState(detector, oldState);
  949.                     stateChanged(newState);

  951.                     // main part
  952.                     final double[] primary    = new double[s.getPrimaryStateDimension()];
  953.                     stateMapper.mapStateToArray(newState, primary, null);

  955.                     // secondary part
  956.                     final double[][] secondary = new double[1][secondaryOffsets.get(SECONDARY_DIMENSION)];
  957.                     for (final AdditionalDerivativesProvider provider : additionalDerivativesProviders) {
  958.                         final String name      = provider.getName();
  959.                         final int    offset    = secondaryOffsets.get(name);
  960.                         final int    dimension = provider.getDimension();
  961.                         System.arraycopy(newState.getAdditionalState(name), 0, secondary[0], offset, dimension);
  962.                     }

  964.                     return new ODEState(newState.getDate().durationFrom(getStartDate()),
  965.                                         primary, secondary);

  967.                 }

  969.             };
  970.         }

  972.     }

  974.     /** Adapt an {@link org.orekit.propagation.sampling.OrekitStepHandler}
  975.      * to Hipparchus {@link ODEStepHandler} interface.
  976.      * @author Luc Maisonobe
  977.      */
  978.     private class AdaptedStepHandler implements ODEStepHandler {

  980.         /** Underlying handler. */
  981.         private final OrekitStepHandler handler;

  983.         /** Build an instance.
  984.          * @param handler underlying handler to wrap
  985.          */
  986.         AdaptedStepHandler(final OrekitStepHandler handler) {
  987.             this.handler = handler;
  988.         }

  990.         /** {@inheritDoc} */
  991.         public void init(final ODEStateAndDerivative s0, final double t) {
  992.             handler.init(convert(s0), stateMapper.mapDoubleToDate(t));
  993.         }

  995.         /** {@inheritDoc} */
  996.         @Override
  997.         public void handleStep(final ODEStateInterpolator interpolator) {
  998.             handler.handleStep(new AdaptedStepInterpolator(interpolator));
  999.         }

  1001.         /** {@inheritDoc} */
  1002.         @Override
  1003.         public void finish(final ODEStateAndDerivative finalState) {
  1004.             handler.finish(convert(finalState));
  1005.         }

  1007.     }

  1009.     /** Adapt an Hipparchus {@link ODEStateInterpolator}
  1010.      * to an orekit {@link OrekitStepInterpolator} interface.
  1011.      * @author Luc Maisonobe
  1012.      */
  1013.     private class AdaptedStepInterpolator implements OrekitStepInterpolator {

  1015.         /** Underlying raw rawInterpolator. */
  1016.         private final ODEStateInterpolator mathInterpolator;

  1018.         /** Simple constructor.
  1019.          * @param mathInterpolator underlying raw interpolator
  1020.          */
  1021.         AdaptedStepInterpolator(final ODEStateInterpolator mathInterpolator) {
  1022.             this.mathInterpolator = mathInterpolator;
  1023.         }

  1025.         /** {@inheritDoc}} */
  1026.         @Override
  1027.         public SpacecraftState getPreviousState() {
  1028.             return convert(mathInterpolator.getPreviousState());
  1029.         }

  1031.         /** {@inheritDoc}} */
  1032.         @Override
  1033.         public boolean isPreviousStateInterpolated() {
  1034.             return mathInterpolator.isPreviousStateInterpolated();
  1035.         }

  1037.         /** {@inheritDoc}} */
  1038.         @Override
  1039.         public SpacecraftState getCurrentState() {
  1040.             return convert(mathInterpolator.getCurrentState());
  1041.         }

  1043.         /** {@inheritDoc}} */
  1044.         @Override
  1045.         public boolean isCurrentStateInterpolated() {
  1046.             return mathInterpolator.isCurrentStateInterpolated();
  1047.         }

  1049.         /** {@inheritDoc}} */
  1050.         @Override
  1051.         public SpacecraftState getInterpolatedState(final AbsoluteDate date) {
  1052.             return convert(mathInterpolator.getInterpolatedState(date.durationFrom(stateMapper.getReferenceDate())));
  1053.         }

  1055.         /** {@inheritDoc}} */
  1056.         @Override
  1057.         public boolean isForward() {
  1058.             return mathInterpolator.isForward();
  1059.         }

  1061.         /** {@inheritDoc}} */
  1062.         @Override
  1063.         public AdaptedStepInterpolator restrictStep(final SpacecraftState newPreviousState,
  1064.                                                     final SpacecraftState newCurrentState) {
  1065.             try {
  1066.                 final AbstractODEStateInterpolator aosi = (AbstractODEStateInterpolator) mathInterpolator;
  1067.                 return new AdaptedStepInterpolator(aosi.restrictStep(convert(newPreviousState),
  1068.                                                                      convert(newCurrentState)));
  1069.             } catch (ClassCastException cce) {
  1070.                 // this should never happen
  1071.                 throw new OrekitInternalError(cce);
  1072.             }
  1073.         }

  1075.     }

  1077.     /** Specialized step handler storing interpolators for ephemeris generation.
  1078.      * @since 11.0
  1079.      */
  1080.     private class StoringStepHandler implements ODEStepHandler, EphemerisGenerator {

  1082.         /** Underlying raw mathematical model. */
  1083.         private DenseOutputModel model;

  1085.         /** the user supplied end date. Propagation may not end on this date. */
  1086.         private AbsoluteDate endDate;

  1088.         /** Generated ephemeris. */
  1089.         private BoundedPropagator ephemeris;

  1091.         /** Last interpolator handled by the object.*/
  1092.         private  ODEStateInterpolator lastInterpolator;

  1094.         /** Set the end date.
  1095.          * @param endDate end date
  1096.          */
  1097.         public void setEndDate(final AbsoluteDate endDate) {
  1098.             this.endDate = endDate;
  1099.         }

  1101.         /** {@inheritDoc} */
  1102.         @Override
  1103.         public void init(final ODEStateAndDerivative s0, final double t) {

  1105.             this.model = new DenseOutputModel();
  1106.             model.init(s0, t);

  1108.             // ephemeris will be generated when last step is processed
  1109.             this.ephemeris = null;

  1111.             this.lastInterpolator = null;

  1113.         }

  1115.         /** {@inheritDoc} */
  1116.         @Override
  1117.         public BoundedPropagator getGeneratedEphemeris() {
  1118.             // Each time we try to get the ephemeris, rebuild it using the last data.
  1119.             buildEphemeris();
  1120.             return ephemeris;
  1121.         }

  1123.         /** {@inheritDoc} */
  1124.         @Override
  1125.         public void handleStep(final ODEStateInterpolator interpolator) {
  1126.             model.handleStep(interpolator);
  1127.             lastInterpolator = interpolator;
  1128.         }

  1130.         /** {@inheritDoc} */
  1131.         @Override
  1132.         public void finish(final ODEStateAndDerivative finalState) {
  1133.             buildEphemeris();
  1134.         }

  1136.         /** Method used to produce ephemeris at a given time.
  1137.          * Can be used at multiple times, updating the ephemeris to
  1138.          * its last state.
  1139.          */
  1140.         private void buildEphemeris() {
  1141.             // buildEphemeris was built in order to allow access to what was previously the finish method.
  1142.             // This now allows to call it through getGeneratedEphemeris, therefore through an external call,
  1143.             // which was not previously the case.

  1145.             // Update the model's finalTime with the last interpolator.
  1146.             model.finish(lastInterpolator.getCurrentState());

  1148.             // set up the boundary dates
  1149.             final double tI = model.getInitialTime();
  1150.             final double tF = model.getFinalTime();
  1151.             // tI is almost? always zero
  1152.             final AbsoluteDate startDate =
  1153.                             stateMapper.mapDoubleToDate(tI);
  1154.             final AbsoluteDate finalDate =
  1155.                             stateMapper.mapDoubleToDate(tF, this.endDate);
  1156.             final AbsoluteDate minDate;
  1157.             final AbsoluteDate maxDate;
  1158.             if (tF < tI) {
  1159.                 minDate = finalDate;
  1160.                 maxDate = startDate;
  1161.             } else {
  1162.                 minDate = startDate;
  1163.                 maxDate = finalDate;
  1164.             }

  1166.             // get the initial additional states that are not managed
  1167.             final DoubleArrayDictionary unmanaged = new DoubleArrayDictionary();
  1168.             for (final DoubleArrayDictionary.Entry initial : getInitialState().getAdditionalStatesValues().getData()) {
  1169.                 if (!isAdditionalStateManaged(initial.getKey())) {
  1170.                     // this additional state was in the initial state, but is unknown to the propagator
  1171.                     // we simply copy its initial value as is
  1172.                     unmanaged.put(initial.getKey(), initial.getValue());
  1173.                 }
  1174.             }

  1176.             // get the names of additional states managed by differential equations
  1177.             final String[] names      = new String[additionalDerivativesProviders.size()];
  1178.             final int[]    dimensions = new int[additionalDerivativesProviders.size()];
  1179.             for (int i = 0; i < names.length; ++i) {
  1180.                 names[i] = additionalDerivativesProviders.get(i).getName();
  1181.                 dimensions[i] = additionalDerivativesProviders.get(i).getDimension();
  1182.             }

  1184.             // create the ephemeris
  1185.             ephemeris = new IntegratedEphemeris(startDate, minDate, maxDate,
  1186.                                                 stateMapper, propagationType, model,
  1187.                                                 unmanaged, getAdditionalStateProviders(),
  1188.                                                 names, dimensions);

  1190.         }

  1192.     }

  1194.     /** Wrapper for resetting an integrator handlers.
  1195.      * <p>
  1196.      * This class is intended to be used in a try-with-resource statement.
  1197.      * If propagator-specific event handlers and step handlers are added to
  1198.      * the integrator in the try block, they will be removed automatically
  1199.      * when leaving the block, so the integrator only keeps its own handlers
  1200.      * between calls to {@link AbstractIntegratedPropagator#propagate(AbsoluteDate, AbsoluteDate).
  1201.      * </p>
  1202.      * @since 11.0
  1203.      */
  1204.     private static class IntegratorResetter implements AutoCloseable {

  1206.         /** Wrapped integrator. */
  1207.         private final ODEIntegrator integrator;

  1209.         /** Initial event detectors list. */
  1210.         private final List<ODEEventDetector> detectors;

  1212.         /** Initial step handlers list. */
  1213.         private final List<ODEStepHandler> stepHandlers;

  1215.         /** Simple constructor.
  1216.          * @param integrator wrapped integrator
  1217.          */
  1218.         IntegratorResetter(final ODEIntegrator integrator) {
  1219.             this.integrator   = integrator;
  1220.             this.detectors    = new ArrayList<>(integrator.getEventDetectors());
  1221.             this.stepHandlers = new ArrayList<>(integrator.getStepHandlers());
  1222.         }

  1224.         /** {@inheritDoc}
  1225.          * <p>
  1226.          * Reset event handlers and step handlers back to the initial list
  1227.          * </p>
  1228.          */
  1229.         @Override
  1230.         public void close() {

  1232.             // reset event handlers
  1233.             integrator.clearEventDetectors();
  1234.             detectors.forEach(integrator::addEventDetector);

  1236.             // reset step handlers
  1237.             integrator.clearStepHandlers();
  1238.             stepHandlers.forEach(integrator::addStepHandler);

  1240.         }

  1242.     }

  1244. }
Created with JaCoCo 0.8.11.202310140853