FieldAbstractIntegratedPropagator.java

  1. /* Copyright 2002-2020 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.Collection;
  21. import java.util.Collections;
  22. import java.util.HashMap;
  23. import java.util.List;
  24. import java.util.Map;

  26. import org.hipparchus.Field;
  27. import org.hipparchus.RealFieldElement;
  28. import org.hipparchus.exception.MathIllegalArgumentException;
  29. import org.hipparchus.exception.MathIllegalStateException;
  30. import org.hipparchus.ode.FieldDenseOutputModel;
  31. import org.hipparchus.ode.FieldEquationsMapper;
  32. import org.hipparchus.ode.FieldExpandableODE;
  33. import org.hipparchus.ode.FieldODEIntegrator;
  34. import org.hipparchus.ode.FieldODEState;
  35. import org.hipparchus.ode.FieldODEStateAndDerivative;
  36. import org.hipparchus.ode.FieldOrdinaryDifferentialEquation;
  37. import org.hipparchus.ode.FieldSecondaryODE;
  38. import org.hipparchus.ode.events.Action;
  39. import org.hipparchus.ode.events.FieldODEEventHandler;
  40. import org.hipparchus.ode.sampling.FieldODEStateInterpolator;
  41. import org.hipparchus.ode.sampling.FieldODEStepHandler;
  42. import org.hipparchus.util.MathArrays;
  43. import org.hipparchus.util.Precision;
  44. import org.orekit.attitudes.AttitudeProvider;
  45. import org.orekit.errors.OrekitException;
  46. import org.orekit.errors.OrekitIllegalStateException;
  47. import org.orekit.errors.OrekitMessages;
  48. import org.orekit.frames.Frame;
  49. import org.orekit.orbits.OrbitType;
  50. import org.orekit.orbits.PositionAngle;
  51. import org.orekit.propagation.FieldAbstractPropagator;
  52. import org.orekit.propagation.FieldBoundedPropagator;
  53. import org.orekit.propagation.FieldSpacecraftState;
  54. import org.orekit.propagation.PropagationType;
  55. import org.orekit.propagation.events.FieldEventDetector;
  56. import org.orekit.propagation.sampling.FieldOrekitStepHandler;
  57. import org.orekit.propagation.sampling.FieldOrekitStepInterpolator;
  58. import org.orekit.time.FieldAbsoluteDate;


  61. /** Common handling of {@link org.orekit.propagation.FieldPropagator FieldPropagator}
  62.  *  methods for both numerical and semi-analytical propagators.
  63.  *  @author Luc Maisonobe
  64.  */
  65. public abstract class FieldAbstractIntegratedPropagator<T extends RealFieldElement<T>> extends FieldAbstractPropagator<T> {

  67.     /** Event detectors not related to force models. */
  68.     private final List<FieldEventDetector<T>> detectors;

  70.     /** Integrator selected by the user for the orbital extrapolation process. */
  71.     private final FieldODEIntegrator<T> integrator;

  73.     /** Mode handler. */
  74.     private FieldModeHandler<T> modeHandler;

  76.     /** Additional equations. */
  77.     private List<FieldAdditionalEquations<T>> additionalEquations;

  79.     /** Counter for differential equations calls. */
  80.     private int calls;

  82.     /** Mapper between raw double components and space flight dynamics objects. */
  83.     private FieldStateMapper<T> stateMapper;

  85.     /** Equations mapper. */
  86.     private FieldEquationsMapper<T> equationsMapper;

  88.     /** Underlying raw rawInterpolator. */
  89.     private FieldODEStateInterpolator<T> mathInterpolator;

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

  94.     /** Type of orbit to output (mean or osculating) <br/>
  95.      * <p>
  96.      * This is used only in the case of semianalitical propagators where there is a clear separation between
  97.      * mean and short periodic elements. It is ignored by the Numerical propagator.
  98.      * </p>
  99.      */
  100.     private PropagationType propagationType;

  102.     /** Build a new instance.
  103.      * @param integrator numerical integrator to use for propagation.
  104.      * @param propagationType type of orbit to output (mean or osculating).
  105.      * @param field Field used by default
  106.      */
  107.     protected FieldAbstractIntegratedPropagator(final Field<T> field, final FieldODEIntegrator<T> integrator, final PropagationType propagationType) {
  108.         super(field);
  109.         detectors            = new ArrayList<FieldEventDetector<T>>();
  110.         additionalEquations  = new ArrayList<FieldAdditionalEquations<T>>();
  111.         this.integrator      = integrator;
  112.         this.propagationType = propagationType;
  113.         this.resetAtEnd      = true;
  114.     }

  116.     /** Allow/disallow resetting the initial state at end of propagation.
  117.      * <p>
  118.      * By default, at the end of the propagation, the propagator resets the initial state
  119.      * to the final state, thus allowing a new propagation to be started from there without
  120.      * recomputing the part already performed. Calling this method with {@code resetAtEnd} set
  121.      * to false changes prevents such reset.
  122.      * </p>
  123.      * @param resetAtEnd if true, at end of each propagation, the {@link
  124.      * #getInitialState() initial state} will be reset to the final state of
  125.      * the propagation, otherwise the initial state will be preserved
  126.      * @since 9.0
  127.      */
  128.     public void setResetAtEnd(final boolean resetAtEnd) {
  129.         this.resetAtEnd = resetAtEnd;
  130.     }

  132.     /** Initialize the mapper.
  133.      * @param field Field used by default
  134.      */
  135.     protected void initMapper(final Field<T> field) {
  136.         final T zero = field.getZero();
  137.         stateMapper = createMapper(null, zero.add(Double.NaN), null, null, null, null);
  138.     }

  140.     /**  {@inheritDoc} */
  141.     public void setAttitudeProvider(final AttitudeProvider attitudeProvider) {
  142.         super.setAttitudeProvider(attitudeProvider);
  143.         stateMapper = createMapper(stateMapper.getReferenceDate(), stateMapper.getMu(),
  144.                                    stateMapper.getOrbitType(), stateMapper.getPositionAngleType(),
  145.                                    attitudeProvider, stateMapper.getFrame());
  146.     }

  148.     /** Set propagation orbit type.
  149.      * @param orbitType orbit type to use for propagation
  150.      */
  151.     protected void setOrbitType(final OrbitType orbitType) {
  152.         stateMapper = createMapper(stateMapper.getReferenceDate(), stateMapper.getMu(),
  153.                                    orbitType, stateMapper.getPositionAngleType(),
  154.                                    stateMapper.getAttitudeProvider(), stateMapper.getFrame());
  155.     }

  157.     /** Get propagation parameter type.
  158.      * @return orbit type used for propagation
  159.      */
  160.     protected OrbitType getOrbitType() {
  161.         return stateMapper.getOrbitType();
  162.     }

  164.     /** Check if only the mean elements should be used in a semianalitical propagation.
  165.      * @return {@link PropagationType MEAN} if only mean elements have to be used or
  166.      *         {@link PropagationType OSCULATING} if osculating elements have to be also used.
  167.      */
  168.     protected PropagationType isMeanOrbit() {
  169.         return propagationType;
  170.     }

  172.     /** Set position angle type.
  173.      * <p>
  174.      * The position parameter type is meaningful only if {@link
  175.      * #getOrbitType() propagation orbit type}
  176.      * support it. As an example, it is not meaningful for propagation
  177.      * in {@link OrbitType#CARTESIAN Cartesian} parameters.
  178.      * </p>
  179.      * @param positionAngleType angle type to use for propagation
  180.      */
  181.     protected void setPositionAngleType(final PositionAngle positionAngleType) {
  182.         stateMapper = createMapper(stateMapper.getReferenceDate(), stateMapper.getMu(),
  183.                                    stateMapper.getOrbitType(), positionAngleType,
  184.                                    stateMapper.getAttitudeProvider(), stateMapper.getFrame());
  185.     }

  187.     /** Get propagation parameter type.
  188.      * @return angle type to use for propagation
  189.      */
  190.     protected PositionAngle getPositionAngleType() {
  191.         return stateMapper.getPositionAngleType();
  192.     }

  194.     /** Set the central attraction coefficient μ.
  195.      * @param mu central attraction coefficient (m³/s²)
  196.      */
  197.     public void setMu(final T mu) {
  198.         stateMapper = createMapper(stateMapper.getReferenceDate(), mu,
  199.                                    stateMapper.getOrbitType(), stateMapper.getPositionAngleType(),
  200.                                    stateMapper.getAttitudeProvider(), stateMapper.getFrame());
  201.     }

  203.     /** Get the central attraction coefficient μ.
  204.      * @return mu central attraction coefficient (m³/s²)
  205.      * @see #setMu(RealFieldElement)
  206.      */
  207.     public T getMu() {
  208.         return stateMapper.getMu();
  209.     }

  211.     /** Get the number of calls to the differential equations computation method.
  212.      * <p>The number of calls is reset each time the {@link #propagate(FieldAbsoluteDate)}
  213.      * method is called.</p>
  214.      * @return number of calls to the differential equations computation method
  215.      */
  216.     public int getCalls() {
  217.         return calls;
  218.     }

  220.     /** {@inheritDoc} */
  221.     @Override
  222.     public boolean isAdditionalStateManaged(final String name) {

  224.         // first look at already integrated states
  225.         if (super.isAdditionalStateManaged(name)) {
  226.             return true;
  227.         }

  229.         // then look at states we integrate ourselves
  230.         for (final FieldAdditionalEquations<T> equation : additionalEquations) {
  231.             if (equation.getName().equals(name)) {
  232.                 return true;
  233.             }
  234.         }

  236.         return false;
  237.     }

  239.     /** {@inheritDoc} */
  240.     @Override
  241.     public String[] getManagedAdditionalStates() {
  242.         final String[] alreadyIntegrated = super.getManagedAdditionalStates();
  243.         final String[] managed = new String[alreadyIntegrated.length + additionalEquations.size()];
  244.         System.arraycopy(alreadyIntegrated, 0, managed, 0, alreadyIntegrated.length);
  245.         for (int i = 0; i < additionalEquations.size(); ++i) {
  246.             managed[i + alreadyIntegrated.length] = additionalEquations.get(i).getName();
  247.         }
  248.         return managed;
  249.     }

  251.     /** Add a set of user-specified equations to be integrated along with the orbit propagation.
  252.      * @param additional additional equations
  253.      */
  254.     public void addAdditionalEquations(final FieldAdditionalEquations<T> additional) {

  256.         // check if the name is already used
  257.         if (isAdditionalStateManaged(additional.getName())) {
  258.             // this set of equations is already registered, complain
  259.             throw new OrekitException(OrekitMessages.ADDITIONAL_STATE_NAME_ALREADY_IN_USE,
  260.                                       additional.getName());
  261.         }

  263.         // this is really a new set of equations, add it
  264.         additionalEquations.add(additional);

  266.     }

  268.     /** {@inheritDoc} */
  269.     public <D extends FieldEventDetector<T>> void addEventDetector(final D detector) {
  270.         detectors.add(detector);
  271.     }

  273.     /** {@inheritDoc} */
  274.     public Collection<FieldEventDetector<T>> getEventsDetectors() {
  275.         return Collections.unmodifiableCollection(detectors);
  276.     }

  278.     /** {@inheritDoc} */
  279.     public void clearEventsDetectors() {
  280.         detectors.clear();
  281.     }

  283.     /** Set up all user defined event detectors.
  284.      */
  285.     protected void setUpUserEventDetectors() {
  286.         for (final FieldEventDetector<T> detector : detectors) {
  287.             setUpEventDetector(integrator, detector);
  288.         }
  289.     }

  291.     /** Wrap an Orekit event detector and register it to the integrator.
  292.      * @param integ integrator into which event detector should be registered
  293.      * @param detector event detector to wrap
  294.      */
  295.     protected void setUpEventDetector(final FieldODEIntegrator<T> integ, final FieldEventDetector<T> detector) {
  296.         integ.addEventHandler(new FieldAdaptedEventDetector(detector),
  297.                               detector.getMaxCheckInterval().getReal(),
  298.                               detector.getThreshold().getReal(),
  299.                               detector.getMaxIterationCount());
  300.     }

  302.     /** {@inheritDoc}
  303.      * <p>Note that this method has the side effect of replacing the step handlers
  304.      * of the underlying integrator set up in the {@link
  305.      * #FieldAbstractIntegratedPropagator(Field, FieldODEIntegrator, PropagationType) constructor}. So if a specific
  306.      * step handler is needed, it should be added after this method has been callled.</p>
  307.      */
  308.     public void setSlaveMode() {
  309.         super.setSlaveMode();
  310.         if (integrator != null) {
  311.             integrator.clearStepHandlers();
  312.         }
  313.         modeHandler = null;
  314.     }

  316.     /** {@inheritDoc}
  317.      * <p>Note that this method has the side effect of replacing the step handlers
  318.      * of the underlying integrator set up in the {@link
  319.      * #FieldAbstractIntegratedPropagator(Field, FieldODEIntegrator, PropagationType) constructor}. So if a specific
  320.      * step handler is needed, it should be added after this method has been called.</p>
  321.      */
  322.     public void setMasterMode(final FieldOrekitStepHandler<T> handler) {
  323.         super.setMasterMode(handler);
  324.         integrator.clearStepHandlers();
  325.         final FieldAdaptedStepHandler wrapped = new FieldAdaptedStepHandler(handler);
  326.         integrator.addStepHandler(wrapped);
  327.         modeHandler = wrapped;
  328.     }

  330.     /** {@inheritDoc}
  331.      * <p>Note that this method has the side effect of replacing the step handlers
  332.      * of the underlying integrator set up in the {@link
  333.      * #FieldAbstractIntegratedPropagator(Field, FieldODEIntegrator, PropagationType) constructor}. So if a specific
  334.      * step handler is needed, it should be added after this method has been called.</p>
  335.      */
  336.     public void setEphemerisMode() {
  337.         super.setEphemerisMode();
  338.         integrator.clearStepHandlers();
  339.         final FieldEphemerisModeHandler ephemeris = new FieldEphemerisModeHandler();
  340.         modeHandler = ephemeris;
  341.         integrator.addStepHandler(ephemeris);
  342.     }

  344.     /** {@inheritDoc} */
  345.     public FieldBoundedPropagator<T> getGeneratedEphemeris()
  346.         throws IllegalStateException {
  347.         if (getMode() != EPHEMERIS_GENERATION_MODE) {
  348.             throw new OrekitIllegalStateException(OrekitMessages.PROPAGATOR_NOT_IN_EPHEMERIS_GENERATION_MODE);
  349.         }
  350.         return ((FieldEphemerisModeHandler) modeHandler).getEphemeris();
  351.     }

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

  373.     /** Get the differential equations to integrate (for main state only).
  374.      * @param integ numerical integrator to use for propagation.
  375.      * @return differential equations for main state
  376.      */
  377.     protected abstract MainStateEquations<T> getMainStateEquations(FieldODEIntegrator<T> integ);

  379.     /** {@inheritDoc} */
  380.     public FieldSpacecraftState<T> propagate(final FieldAbsoluteDate<T> target) {
  381.         try {
  382.             if (getStartDate() == null) {
  383.                 if (getInitialState() == null) {
  384.                     throw new OrekitException(OrekitMessages.INITIAL_STATE_NOT_SPECIFIED_FOR_ORBIT_PROPAGATION);
  385.                 }
  386.                 setStartDate(getInitialState().getDate());
  387.             }
  388.             return propagate(getStartDate(), target);
  389.         } catch (OrekitException oe) {

  391.             // recover a possible embedded OrekitException
  392.             for (Throwable t = oe; t != null; t = t.getCause()) {
  393.                 if (t instanceof OrekitException) {
  394.                     throw (OrekitException) t;
  395.                 }
  396.             }
  397.             throw new OrekitException(oe);

  399.         }
  400.     }

  402.     /** {@inheritDoc} */
  403.     public FieldSpacecraftState<T> propagate(final FieldAbsoluteDate<T> tStart, final FieldAbsoluteDate<T> tEnd) {
  404.         try {

  406.             if (getInitialState() == null) {
  407.                 throw new OrekitException(OrekitMessages.INITIAL_STATE_NOT_SPECIFIED_FOR_ORBIT_PROPAGATION);
  408.             }

  410.             if (!tStart.equals(getInitialState().getDate())) {
  411.                 // if propagation start date is not initial date,
  412.                 // propagate from initial to start date without event detection
  413.                 propagate(tStart, false);
  414.             }

  416.             // propagate from start date to end date with event detection
  417.             return propagate(tEnd, true);

  419.         } catch (OrekitException oe) {

  421.             // recover a possible embedded OrekitException
  422.             for (Throwable t = oe; t != null; t = t.getCause()) {
  423.                 if (t instanceof OrekitException) {
  424.                     throw (OrekitException) t;
  425.                 }
  426.             }
  427.             throw new OrekitException(oe);

  429.         }
  430.     }

  432.     /** Propagation with or without event detection.
  433.      * @param tEnd target date to which orbit should be propagated
  434.      * @param activateHandlers if true, step and event handlers should be activated
  435.      * @return state at end of propagation
  436.      */
  437.     protected FieldSpacecraftState<T> propagate(final FieldAbsoluteDate<T> tEnd, final boolean activateHandlers) {
  438.         try {

  440.             initializePropagation();

  442.             if (getInitialState().getDate().equals(tEnd)) {
  443.                 // don't extrapolate
  444.                 return getInitialState();
  445.             }
  446.             // space dynamics view
  447.             stateMapper = createMapper(getInitialState().getDate(), stateMapper.getMu(),
  448.                                        stateMapper.getOrbitType(), stateMapper.getPositionAngleType(),
  449.                                        stateMapper.getAttitudeProvider(), getInitialState().getFrame());


  452.             // set propagation orbit type
  453.             //final FieldOrbit<T> initialOrbit = stateMapper.getOrbitType().convertType(getInitialState().getOrbit());
  454.             if (Double.isNaN(getMu().getReal())) {
  455.                 setMu(getInitialState().getMu());
  456.             }
  457.             if (getInitialState().getMass().getReal() <= 0.0) {
  458.                 throw new OrekitException(OrekitMessages.SPACECRAFT_MASS_BECOMES_NEGATIVE,
  459.                                                getInitialState().getMass());
  460.             }

  462.             integrator.clearEventHandlers();
  463.             // set up events added by user
  464.             setUpUserEventDetectors();

  466.             // convert space flight dynamics API to math API
  467.             final FieldSpacecraftState<T> initialIntegrationState = getInitialIntegrationState();
  468.             final FieldODEState<T> mathInitialState = createInitialState(initialIntegrationState);
  469.             final FieldExpandableODE<T> mathODE = createODE(integrator, mathInitialState);
  470.             equationsMapper = mathODE.getMapper();
  471.             mathInterpolator = null;
  472.             // initialize mode handler
  473.             if (modeHandler != null) {
  474.                 modeHandler.initialize(activateHandlers, tEnd);
  475.             }
  476.             // mathematical integration
  477.             final FieldODEStateAndDerivative<T> mathFinalState;

  479.             beforeIntegration(initialIntegrationState, tEnd);
  480.             mathFinalState = integrator.integrate(mathODE, mathInitialState,
  481.                                                   tEnd.durationFrom(getInitialState().getDate()));

  483.             afterIntegration();

  485.             // get final state
  486.             FieldSpacecraftState<T> finalState =
  487.                             stateMapper.mapArrayToState(stateMapper.mapDoubleToDate(mathFinalState.getTime(), tEnd),
  488.                                                         mathFinalState.getPrimaryState(),
  489.                                                         mathFinalState.getPrimaryDerivative(),
  490.                                                         propagationType);
  491.             finalState = updateAdditionalStates(finalState);
  492.             for (int i = 0; i < additionalEquations.size(); ++i) {
  493.                 final T[] secondary = mathFinalState.getSecondaryState(i + 1);
  494.                 finalState = finalState.addAdditionalState(additionalEquations.get(i).getName(),
  495.                                                            secondary);
  496.             }
  497.             if (resetAtEnd) {
  498.                 resetInitialState(finalState);
  499.                 setStartDate(finalState.getDate());
  500.             }

  502.             return finalState;

  504.         } catch (OrekitException pe) {
  505.             throw pe;
  506.         } catch (MathIllegalArgumentException miae) {
  507.             throw OrekitException.unwrap(miae);
  508.         } catch (MathIllegalStateException mise) {
  509.             throw OrekitException.unwrap(mise);
  510.         }
  511.     }

  513.     /** Get the initial state for integration.
  514.      * @return initial state for integration
  515.      */
  516.     protected FieldSpacecraftState<T> getInitialIntegrationState() {
  517.         return getInitialState();
  518.     }

  520.     /** Create an initial state.
  521.      * @param initialState initial state in flight dynamics world
  522.      * @return initial state in mathematics world
  523.      */
  524.     private FieldODEState<T> createInitialState(final FieldSpacecraftState<T> initialState) {

  526.         // retrieve initial state
  527.         final T[] primary  = MathArrays.buildArray(initialState.getA().getField(), getBasicDimension());
  528.         stateMapper.mapStateToArray(initialState, primary, null);

  530.         // secondary part of the ODE
  531.         final T[][] secondary = MathArrays.buildArray(initialState.getA().getField(), additionalEquations.size(), -1);
  532.         for (int i = 0; i < additionalEquations.size(); ++i) {
  533.             final FieldAdditionalEquations<T> additional = additionalEquations.get(i);
  534.             final T[] addState = getInitialState().getAdditionalState(additional.getName());
  535.             secondary[i] = MathArrays.buildArray(initialState.getA().getField(), addState.length);
  536.             for (int j = 0; j < addState.length; j++) {
  537.                 secondary[i][j] = addState[j];
  538.             }
  539.         }

  541.         return new FieldODEState<>(initialState.getA().getField().getZero(), primary, secondary);

  543.     }

  545.     /** Create an ODE with all equations.
  546.      * @param integ numerical integrator to use for propagation.
  547.      * @param mathInitialState initial state
  548.      * @return a new ode
  549.      */
  550.     private FieldExpandableODE<T> createODE(final FieldODEIntegrator<T> integ,
  551.                                     final FieldODEState<T> mathInitialState) {

  553.         final FieldExpandableODE<T> ode =
  554.                 new FieldExpandableODE<>(new ConvertedMainStateEquations(getMainStateEquations(integ)));

  556.         // secondary part of the ODE
  557.         for (int i = 0; i < additionalEquations.size(); ++i) {
  558.             final FieldAdditionalEquations<T> additional = additionalEquations.get(i);
  559.             final FieldSecondaryODE<T> secondary =
  560.                     new ConvertedSecondaryStateEquations(additional,
  561.                                                          mathInitialState.getSecondaryStateDimension(i + 1));
  562.             ode.addSecondaryEquations(secondary);
  563.         }

  565.         return ode;

  567.     }

  569.     /** Method called just before integration.
  570.      * <p>
  571.      * The default implementation does nothing, it may be specialized in subclasses.
  572.      * </p>
  573.      * @param initialState initial state
  574.      * @param tEnd target date at which state should be propagated
  575.      */
  576.     protected void beforeIntegration(final FieldSpacecraftState<T> initialState,
  577.                                      final FieldAbsoluteDate<T> tEnd) {
  578.         // do nothing by default
  579.     }

  581.     /** Method called just after integration.
  582.      * <p>
  583.      * The default implementation does nothing, it may be specialized in subclasses.
  584.      * </p>
  585.      */
  586.     protected void afterIntegration() {
  587.         // do nothing by default
  588.     }

  590.     /** Get state vector dimension without additional parameters.
  591.      * @return state vector dimension without additional parameters.
  592.      */
  593.     public int getBasicDimension() {
  594.         return 7;

  596.     }

  598.     /** Get the integrator used by the propagator.
  599.      * @return the integrator.
  600.      */
  601.     protected FieldODEIntegrator<T> getIntegrator() {
  602.         return integrator;
  603.     }

  605.     /** Get a complete state with all additional equations.
  606.      * @param t current value of the independent <I>time</I> variable
  607.      * @param ts array containing the current value of the state vector
  608.      * @param tsDot array containing the current value of the state vector derivative
  609.      * @return complete state
  610.      */
  611.     private FieldSpacecraftState<T> getCompleteState(final T t, final T[] ts, final T[] tsDot) {

  613.         // main state
  614.         FieldSpacecraftState<T> state = stateMapper.mapArrayToState(t, ts, tsDot, PropagationType.MEAN);  //not sure of the mean orbit, should be true
  615.         // pre-integrated additional states
  616.         state = updateAdditionalStates(state);

  618.         // additional states integrated here
  619.         if (!additionalEquations.isEmpty()) {

  621.             for (int i = 0; i < additionalEquations.size(); ++i) {
  622.                 state = state.addAdditionalState(additionalEquations.get(i).getName(),
  623.                                                  equationsMapper.extractEquationData(i + 1, ts));
  624.             }

  626.         }

  628.         return state;

  630.     }

  632.     /** Differential equations for the main state (orbit, attitude and mass). */
  633.     public interface MainStateEquations<T extends RealFieldElement<T>> {

  635.         /**
  636.          * Initialize the equations at the start of propagation. This method will be
  637.          * called before any calls to {@link #computeDerivatives(FieldSpacecraftState)}.
  638.          *
  639.          * <p> The default implementation of this method does nothing.
  640.          *
  641.          * @param initialState initial state information at the start of propagation.
  642.          * @param target       date of propagation. Not equal to {@code
  643.          *                     initialState.getDate()}.
  644.          */
  645.         void init(FieldSpacecraftState<T> initialState, FieldAbsoluteDate<T> target);

  647.         /** Compute differential equations for main state.
  648.          * @param state current state
  649.          * @return derivatives of main state
  650.          */
  651.         T[] computeDerivatives(FieldSpacecraftState<T> state);

  653.     }

  655.     /** Differential equations for the main state (orbit, attitude and mass), with converted API. */
  656.     private class ConvertedMainStateEquations implements FieldOrdinaryDifferentialEquation<T> {

  658.         /** Main state equations. */
  659.         private final MainStateEquations<T> main;

  661.         /** Simple constructor.
  662.          * @param main main state equations
  663.          */
  664.         ConvertedMainStateEquations(final MainStateEquations<T> main) {
  665.             this.main = main;
  666.             calls = 0;
  667.         }

  669.         /** {@inheritDoc} */
  670.         public int getDimension() {
  671.             return getBasicDimension();
  672.         }

  674.         @Override
  675.         public void init(final T t0, final T[] y0, final T finalTime) {
  676.             // update space dynamics view
  677.             FieldSpacecraftState<T> initialState = stateMapper.mapArrayToState(t0, y0, null, PropagationType.MEAN);
  678.             initialState = updateAdditionalStates(initialState);
  679.             final FieldAbsoluteDate<T> target = stateMapper.mapDoubleToDate(finalTime);
  680.             main.init(initialState, target);
  681.         }
  682.         /** {@inheritDoc} */
  683.         public T[] computeDerivatives(final T t, final T[] y) {

  685.             // increment calls counter
  686.             ++calls;

  688.             // update space dynamics view
  689.             FieldSpacecraftState<T> currentState = stateMapper.mapArrayToState(t, y, null, PropagationType.MEAN);
  690.             currentState = updateAdditionalStates(currentState);

  692.             // compute main state differentials
  693.             return main.computeDerivatives(currentState);

  695.         }

  697.     }

  699.     /** Differential equations for the secondary state (Jacobians, user variables ...), with converted API. */
  700.     private class ConvertedSecondaryStateEquations implements FieldSecondaryODE<T> {

  702.         /** Additional equations. */
  703.         private final FieldAdditionalEquations<T> equations;

  705.         /** Dimension of the additional state. */
  706.         private final int dimension;

  708.         /** Simple constructor.
  709.          * @param equations additional equations
  710.          * @param dimension dimension of the additional state
  711.          */
  712.         ConvertedSecondaryStateEquations(final FieldAdditionalEquations<T> equations,
  713.                                          final int dimension) {
  714.             this.equations = equations;
  715.             this.dimension = dimension;
  716.         }

  718.         /** {@inheritDoc} */
  719.         @Override
  720.         public int getDimension() {
  721.             return dimension;
  722.         }

  724.         /** {@inheritDoc} */
  725.         @Override
  726.         public void init(final T t0, final T[] primary0,
  727.                          final T[] secondary0, final T finalTime) {
  728.             // update space dynamics view
  729.             FieldSpacecraftState<T> initialState = stateMapper.mapArrayToState(t0, primary0, null, PropagationType.MEAN);
  730.             initialState = updateAdditionalStates(initialState);
  731.             initialState = initialState.addAdditionalState(equations.getName(), secondary0);
  732.             final FieldAbsoluteDate<T> target = stateMapper.mapDoubleToDate(finalTime);
  733.             equations.init(initialState, target);
  734.         }

  736.         /** {@inheritDoc} */
  737.         @Override
  738.         public T[] computeDerivatives(final T t, final T[] primary,
  739.                                       final T[] primaryDot, final T[] secondary) {

  741.             // update space dynamics view
  742.             FieldSpacecraftState<T> currentState = stateMapper.mapArrayToState(t, primary, primaryDot, PropagationType.MEAN);
  743.             currentState = updateAdditionalStates(currentState);
  744.             currentState = currentState.addAdditionalState(equations.getName(), secondary);

  746.             // compute additional derivatives
  747.             final T[] secondaryDot = MathArrays.buildArray(getField(), secondary.length);
  748.             final T[] additionalMainDot =
  749.                             equations.computeDerivatives(currentState, secondaryDot);
  750.             if (additionalMainDot != null) {
  751.                 // the additional equations have an effect on main equations
  752.                 for (int i = 0; i < additionalMainDot.length; ++i) {
  753.                     primaryDot[i] = primaryDot[i].add(additionalMainDot[i]);
  754.                 }
  755.             }

  757.             return secondaryDot;

  759.         }

  761.     }

  763.     /** Adapt an {@link org.orekit.propagation.events.FieldEventDetector<T>}
  764.      * to Hipparchus {@link org.hipparchus.ode.events.FieldODEEventHandler<T>} interface.
  765.      * @param <T> class type for the generic version
  766.      * @author Fabien Maussion
  767.      */
  768.     private class FieldAdaptedEventDetector implements FieldODEEventHandler<T> {

  770.         /** Underlying event detector. */
  771.         private final FieldEventDetector<T> detector;

  773.         /** Time of the previous call to g. */
  774.         private T lastT;

  776.         /** Value from the previous call to g. */
  777.         private T lastG;

  779.         /** Build a wrapped event detector.
  780.          * @param detector event detector to wrap
  781.         */
  782.         FieldAdaptedEventDetector(final FieldEventDetector<T> detector) {
  783.             this.detector = detector;
  784.             this.lastT    = getField().getZero().add(Double.NaN);
  785.             this.lastG    = getField().getZero().add(Double.NaN);
  786.         }

  788.         /** {@inheritDoc} */
  789.         public void init(final FieldODEStateAndDerivative<T> s0, final T t) {
  790.             detector.init(getCompleteState(s0.getTime(), s0.getCompleteState(), s0.getCompleteDerivative()),
  791.                           stateMapper.mapDoubleToDate(t));
  792.             this.lastT = getField().getZero().add(Double.NaN);
  793.             this.lastG = getField().getZero().add(Double.NaN);
  794.         }

  796.         /** {@inheritDoc} */
  797.         public T g(final FieldODEStateAndDerivative<T> s) {
  798.             if (!Precision.equals(lastT.getReal(), s.getTime().getReal(), 0)) {
  799.                 lastT = s.getTime();
  800.                 lastG = detector.g(getCompleteState(s.getTime(), s.getCompleteState(), s.getCompleteDerivative()));
  801.             }
  802.             return lastG;
  803.         }

  805.         /** {@inheritDoc} */
  806.         public Action eventOccurred(final FieldODEStateAndDerivative<T> s, final boolean increasing) {
  807.             return detector.eventOccurred(
  808.                     getCompleteState(
  809.                             s.getTime(),
  810.                             s.getCompleteState(),
  811.                             s.getCompleteDerivative()),
  812.                     increasing);
  813.         }

  815.         /** {@inheritDoc} */
  816.         public FieldODEState<T> resetState(final FieldODEStateAndDerivative<T> s) {

  818.             final FieldSpacecraftState<T> oldState = getCompleteState(s.getTime(), s.getCompleteState(), s.getCompleteDerivative());
  819.             final FieldSpacecraftState<T> newState = detector.resetState(oldState);
  820.             stateChanged(newState);

  822.             // main part
  823.             final T[] primary    = MathArrays.buildArray(getField(), s.getPrimaryStateDimension());
  824.             stateMapper.mapStateToArray(newState, primary, null);

  826.             // secondary part
  827.             final T[][] secondary    = MathArrays.buildArray(getField(), additionalEquations.size(), -1);

  829.             for (int i = 0; i < additionalEquations.size(); ++i) {
  830.                 final FieldAdditionalEquations<T> additional = additionalEquations.get(i);
  831.                 final T[] NState = newState.getAdditionalState(additional.getName());
  832.                 secondary[i] = MathArrays.buildArray(getField(), NState.length);
  833.                 for (int j = 0; j < NState.length; j++) {
  834.                     secondary[i][j] = NState[j];
  835.                 }
  836.             }

  838.             return new FieldODEState<>(newState.getDate().durationFrom(getStartDate()),
  839.                                        primary, secondary);
  840.         }

  842.     }

  844.     /** Adapt an {@link org.orekit.propagation.sampling.FieldOrekitStepHandler<T>}
  845.      * to Hipparchus {@link FieldODEStepHandler<T>} interface.
  846.      * @author Luc Maisonobe
  847.      */
  848.     private class FieldAdaptedStepHandler
  849.         implements FieldOrekitStepInterpolator<T>, FieldODEStepHandler<T>, FieldModeHandler<T> {

  851.         /** Underlying handler. */
  852.         private final FieldOrekitStepHandler<T> handler;

  854.         /** Flag for handler . */
  855.         private boolean activate;

  857.         /** Build an instance.
  858.          * @param handler underlying handler to wrap
  859.          */
  860.         FieldAdaptedStepHandler(final FieldOrekitStepHandler<T> handler) {
  861.             this.handler = handler;
  862.         }

  864.         /** {@inheritDoc} */
  865.         public void initialize(final boolean activateHandlers,
  866.                                final FieldAbsoluteDate<T> targetDate) {
  867.             this.activate = activateHandlers;
  868.         }
  869.         /** {@inheritDoc} */
  870.         public void init(final FieldODEStateAndDerivative<T> s0, final T t) {
  871.             handler.init(getCompleteState(s0.getTime(), s0.getCompleteState(), s0.getCompleteDerivative()),
  872.                          stateMapper.mapDoubleToDate(t));
  873.         }

  875.         /** {@inheritDoc} */
  876.         public void handleStep(final FieldODEStateInterpolator<T> interpolator, final boolean isLast) {
  877.             mathInterpolator = interpolator;
  878.             if (activate) {
  879.                 handler.handleStep(this, isLast);
  880.             }
  881.         }

  883.         /** {@inheritDoc}} */
  884.         @Override
  885.         public FieldSpacecraftState<T> getPreviousState() {
  886.             return convert(mathInterpolator.getPreviousState());
  887.         }

  889.         /** {@inheritDoc}} */
  890.         @Override
  891.         public FieldSpacecraftState<T> getCurrentState() {
  892.             return convert(mathInterpolator.getCurrentState());
  893.         }

  895.         /** {@inheritDoc}} */
  896.         @Override
  897.         public FieldSpacecraftState<T> getInterpolatedState(final FieldAbsoluteDate<T> date) {
  898.             return convert(mathInterpolator.getInterpolatedState(date.durationFrom(getStartDate())));
  899.         }

  901.         /** Get the interpolated state.
  902.          * @param os mathematical state
  903.          * @return interpolated state at the current interpolation date
  904.                            * the date
  905.          * @see #getInterpolatedDate()
  906.          * @see #setInterpolatedDate(FieldAbsoluteDate<T>)
  907.          */
  908.         private FieldSpacecraftState<T> convert(final FieldODEStateAndDerivative<T> os) {
  909.             try {

  911.                 FieldSpacecraftState<T> s =
  912.                         stateMapper.mapArrayToState(os.getTime(),
  913.                                                     os.getPrimaryState(),
  914.                                                     os.getPrimaryDerivative(),
  915.                                                     propagationType);
  916.                 s = updateAdditionalStates(s);
  917.                 for (int i = 0; i < additionalEquations.size(); ++i) {
  918.                     final T[] secondary = os.getSecondaryState(i + 1);
  919.                     s = s.addAdditionalState(additionalEquations.get(i).getName(), secondary);
  920.                 }

  922.                 return s;

  924.             } catch (OrekitException oe) {
  925.                 throw new OrekitException(oe);
  926.             }
  927.         }

  929.         /** Check is integration direction is forward in date.
  930.          * @return true if integration is forward in date
  931.          */
  932.         public boolean isForward() {
  933.             return mathInterpolator.isForward();
  934.         }

  936.     }

  938.     private class FieldEphemerisModeHandler implements FieldModeHandler<T>, FieldODEStepHandler<T> {

  940.         /** Underlying raw mathematical model. */
  941.         private FieldDenseOutputModel<T> model;

  943.         /** Generated ephemeris. */
  944.         private FieldBoundedPropagator<T> ephemeris;

  946.         /** Flag for handler . */
  947.         private boolean activate;

  949.         /** the user supplied end date. Propagation may not end on this date. */
  950.         private FieldAbsoluteDate<T> endDate;

  952.         /** Creates a new instance of FieldEphemerisModeHandler which must be
  953.          *  filled by the propagator.
  954.          */
  955.         FieldEphemerisModeHandler() {
  956.         }

  958.         /** {@inheritDoc} */
  959.         public void initialize(final boolean activateHandlers,
  960.                                final FieldAbsoluteDate<T> targetDate) {
  961.             this.activate = activateHandlers;
  962.             this.model    = new FieldDenseOutputModel<>();
  963.             this.endDate  = targetDate;

  965.             // ephemeris will be generated when last step is processed
  966.             this.ephemeris = null;

  968.         }

  970.         /** Get the generated ephemeris.
  971.          * @return a new instance of the generated ephemeris
  972.          */
  973.         public FieldBoundedPropagator<T> getEphemeris() {
  974.             return ephemeris;
  975.         }

  977.         /** {@inheritDoc} */
  978.         public void handleStep(final FieldODEStateInterpolator<T> interpolator, final boolean isLast) {
  979.             if (activate) {
  980.                 model.handleStep(interpolator, isLast);
  981.                 if (isLast) {

  983.                     // set up the boundary dates
  984.                     final T tI = model.getInitialTime();
  985.                     final T tF = model.getFinalTime();
  986.                     // tI is almost? always zero
  987.                     final FieldAbsoluteDate<T> startDate =
  988.                                     stateMapper.mapDoubleToDate(tI);
  989.                     final FieldAbsoluteDate<T> finalDate =
  990.                                     stateMapper.mapDoubleToDate(tF, this.endDate);
  991.                     final FieldAbsoluteDate<T> minDate;
  992.                     final FieldAbsoluteDate<T> maxDate;
  993.                     if (tF.getReal() < tI.getReal()) {
  994.                         minDate = finalDate;
  995.                         maxDate = startDate;
  996.                     } else {
  997.                         minDate = startDate;
  998.                         maxDate = finalDate;
  999.                     }

  1001.                     // get the initial additional states that are not managed
  1002.                     final Map<String, T[]> unmanaged = new HashMap<String, T[]>();
  1003.                     for (final Map.Entry<String, T[]> initial : getInitialState().getAdditionalStates().entrySet()) {
  1004.                         if (!isAdditionalStateManaged(initial.getKey())) {
  1005.                             // this additional state was in the initial state, but is unknown to the propagator
  1006.                             // we simply copy its initial value as is
  1007.                             unmanaged.put(initial.getKey(), initial.getValue());
  1008.                         }
  1009.                     }

  1011.                     // get the names of additional states managed by differential equations
  1012.                     final String[] names = new String[additionalEquations.size()];
  1013.                     for (int i = 0; i < names.length; ++i) {
  1014.                         names[i] = additionalEquations.get(i).getName();
  1015.                     }

  1017.                     // create the ephemeris
  1018.                     ephemeris = new FieldIntegratedEphemeris<>(startDate, minDate, maxDate,
  1019.                                                                stateMapper, propagationType, model, unmanaged,
  1020.                                                                getAdditionalStateProviders(), names);

  1022.                 }

  1024.             }
  1025.         }

  1027.         /** {@inheritDoc} */
  1028.         public void init(final FieldODEStateAndDerivative<T> s0, final T t) {
  1029.             model.init(s0, t);
  1030.         }

  1032.     }

  1034. }
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