PartialDerivativesEquations (ORbit Extrapolation KIT 9.2 API)

java.lang.Object
- org.orekit.propagation.numerical.PartialDerivativesEquations

All Implemented Interfaces:

AdditionalEquations
```
public class PartialDerivativesEquations
extends Object
implements AdditionalEquations
```
Set of additional equations computing the partial derivatives of the state (orbit) with respect to initial state and force models parameters.
This set of equations are automatically added to a numerical propagator in order to compute partial derivatives of the orbit along with the orbit itself. This is useful for example in orbit determination applications.

The partial derivatives with respect to initial state can be either dimension 6 (orbit only) or 7 (orbit and mass).

The partial derivatives with respect to force models parameters has a dimension equal to the number of selected parameters. Parameters selection is implemented at force models level. Users must retrieve a parameter driver using ForceModel.getParameterDriver(String) and then select it by calling setSelected(true).

If several force models provide different drivers for the same parameter name, selecting any of these drivers has the side effect of selecting all the drivers for this shared parameter. In this case, the partial derivatives will be the sum of the partial derivatives contributed by the corresponding force models. This case typically arises for central attraction coefficient, which has an influence on Newtonian attraction, gravity field, and relativity.

Author:

Véronique Pommier-Maurussane, Luc Maisonobe

Constructor Summary

Constructors
Constructor Description

PartialDerivativesEquations(String name, NumericalPropagator propagator)
Simple constructor.

Constructors
Constructor	Description
`PartialDerivativesEquations(String name, NumericalPropagator propagator)`	Simple constructor.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`double[]`	`computeDerivatives(SpacecraftState s, double[] pDot)`	Compute the derivatives related to the additional state parameters.
`JacobiansMapper`	`getMapper()`	Get a mapper between two-dimensional Jacobians and one-dimensional additional state.
`String`	`getName()`	Get the name of the additional state.
`ParameterDriversList`	`getSelectedParameters()`	Get the selected parameters, in Jacobian matrix column order.
`SpacecraftState`	`setInitialJacobians(SpacecraftState s0)`	Set the initial value of the Jacobian with respect to state and parameter.
`SpacecraftState`	`setInitialJacobians(SpacecraftState s1, double[][] dY1dY0, double[][] dY1dP)`	Set the initial value of the Jacobian with respect to state and parameter.
`SpacecraftState`	`setInitialJacobians(SpacecraftState s0, int stateDimension)`	Deprecated. as of 9.0, replaced by `setInitialJacobians(SpacecraftState)`

Methods inherited from interface org.orekit.propagation.integration.AdditionalEquations
init

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - PartialDerivativesEquations
```
public PartialDerivativesEquations(String name,
                                   NumericalPropagator propagator)
                            throws OrekitException
```
    Simple constructor.
    Upon construction, this set of equations is automatically added to the propagator by calling its AbstractIntegratedPropagator.addAdditionalEquations(AdditionalEquations) method. So there is no need to call this method explicitly for these equations.
    
    Parameters:
    
    name - name of the partial derivatives equations
    
    propagator - the propagator that will handle the orbit propagation
    
    Throws:
    
    OrekitException - if a set of equations with the same name is already present
- Method Detail
  - getName
```
public String getName()
```
    Get the name of the additional state.
    
    Specified by:
    
    getName in interface AdditionalEquations
    
    Returns:
    
    name of the additional state
  - getSelectedParameters
```
public ParameterDriversList getSelectedParameters()
                                           throws OrekitException
```
    Get the selected parameters, in Jacobian matrix column order.
    The force models parameters for which partial derivatives are desired, must have been selected before this method is called, so the proper list is returned.
    
    Returns:
    
    selected parameters, in Jacobian matrix column order which is lexicographic order
    
    Throws:
    
    OrekitException - if an existing driver for a parameter throws one when its value is reset using the value from another driver managing the same parameter
  - setInitialJacobians
```
public SpacecraftState setInitialJacobians(SpacecraftState s0)
                                    throws OrekitException
```
    Set the initial value of the Jacobian with respect to state and parameter.
    This method is equivalent to call setInitialJacobians(SpacecraftState, double[][], double[][]) with dYdY0 set to the identity matrix and dYdP set to a zero matrix.
    
    The force models parameters for which partial derivatives are desired, must have been selected before this method is called, so proper matrices dimensions are used.
    
    Parameters:
    
    s0 - initial state
    
    Returns:
    
    state with initial Jacobians added
    
    Throws:
    
    OrekitException - if the partial equation has not been registered in the propagator or if matrices dimensions are incorrect
    
    Since:
    
    9.0
    
    See Also:
    
    getSelectedParameters()
  - setInitialJacobians
```
@Deprecated
public SpacecraftState setInitialJacobians(SpacecraftState s0,
                                           int stateDimension)
                                    throws OrekitException
```
    Deprecated. as of 9.0, replaced by setInitialJacobians(SpacecraftState)
    
    Set the initial value of the Jacobian with respect to state and parameter.
    This method is equivalent to call setInitialJacobians(SpacecraftState, double[][], double[][]) with dYdY0 set to the identity matrix and dYdP set to a zero matrix.
    
    The force models parameters for which partial derivatives are desired, must have been selected before this method is called, so proper matrices dimensions are used.
    
    Parameters:
    
    s0 - initial state
    
    stateDimension - state dimension, must be either 6 for orbit only or 7 for orbit and mass
    
    Returns:
    
    state with initial Jacobians added
    
    Throws:
    
    OrekitException - if the partial equation has not been registered in the propagator or if matrices dimensions are incorrect
    
    See Also:
    
    getSelectedParameters()
  - setInitialJacobians
```
public SpacecraftState setInitialJacobians(SpacecraftState s1,
                                           double[][] dY1dY0,
                                           double[][] dY1dP)
                                    throws OrekitException
```
    Set the initial value of the Jacobian with respect to state and parameter.
    The returned state must be added to the propagator (it is not done automatically, as the user may need to add more states to it).
    
    The force models parameters for which partial derivatives are desired, must have been selected before this method is called, and the dY1dP matrix dimension must be consistent with the selection.
    
    Parameters:
    
    s1 - current state
    
    dY1dY0 - Jacobian of current state at time t₁ with respect to state at some previous time t₀ (must be 6x6)
    
    dY1dP - Jacobian of current state at time t₁ with respect to parameters (may be null if no parameters are selected)
    
    Returns:
    
    state with initial Jacobians added
    
    Throws:
    
    OrekitException - if the partial equation has not been registered in the propagator or if matrices dimensions are incorrect
    
    See Also:
    
    getSelectedParameters()
  - getMapper
```
public JacobiansMapper getMapper()
                          throws OrekitException
```
    Get a mapper between two-dimensional Jacobians and one-dimensional additional state.
    
    Returns:
    
    a mapper between two-dimensional Jacobians and one-dimensional additional state, with the same name as the instance
    
    Throws:
    
    OrekitException - if the initial Jacobians have not been initialized yet
    
    See Also:
    
    setInitialJacobians(SpacecraftState, int), setInitialJacobians(SpacecraftState, double[][], double[][])
  - computeDerivatives
```
public double[] computeDerivatives(SpacecraftState s,
                                   double[] pDot)
                            throws OrekitException
```
    Compute the derivatives related to the additional state parameters.
    When this method is called, the spacecraft state contains the main state (orbit, attitude and mass), all the states provided through the additional state providers registered to the propagator, and the additional state integrated using this equation. It does not contains any other states to be integrated alongside during the same propagation.
    
    Specified by:
    
    computeDerivatives in interface AdditionalEquations
    
    Parameters:
    
    s - current state information: date, kinematics, attitude, and additional state
    
    pDot - placeholder where the derivatives of the additional parameters should be put
    
    Returns:
    
    cumulative effect of the equations on the main state (may be null if equations do not change main state at all)
    
    Throws:
    
    OrekitException - if some specific error occurs

Class PartialDerivativesEquations

Constructor Summary

Method Summary

Methods inherited from interface org.orekit.propagation.integration.AdditionalEquations

Methods inherited from class java.lang.Object

Constructor Detail

PartialDerivativesEquations

Method Detail

getName

getSelectedParameters

setInitialJacobians

setInitialJacobians

setInitialJacobians

getMapper

computeDerivatives