StateTransitionMatrix Class 
An extended state transition matrix, if consider parameters are not used then it functions as a normal state transition matrix: mapping the value of the state parameters from one time to another time.
The state transition matrix represents the transformation from the state at one time to the state at another time. This can be used as an alternative to propagating a state in time with NumericalPropagator, but is more often used in order to find the timevarying covariance of the state. This is because the construction of a StateTransitionMatrix entails the linearization of the state, and in most cases calculating the derivatives of the state transition matrix takes as long or longer as calculating the derivatives of the state.
To find the covariance of a state over time a StateTransitionMatrix is propagated with a NumericalPropagator and the resulting data is used to create the covariance information for the same period using PopulateCovarianceCollection(Matrix, DateMotionCollectionMatrix, TransitionType).
Namespace: AGI.Foundation.Propagators
The StateTransitionMatrix type exposes the following members.
Name  Description  

StateTransitionMatrix  Initializes a new instance.  
StateTransitionMatrix(StateTransitionMatrix, CopyContext)  Initializes a new instance as a copy of an existing instance. 
Name  Description  

ConsiderDimension 
Gets the summed dimension of all of the consider parameters.
 
Dimension 
Gets the number of parameters (per Order) within this element.
(Overrides PropagationStateElementDimension.)  
Identification 
Gets or sets the string identifying this instance in the overall output.
(Inherited from PropagationStateElement.)  
IncludeHighestDerivativeInOutput 
Gets or sets a value indicating whether to include the derivative computed at each step with the output.
If this is true, the output converted from the raw state will contain the derivative
associated with the Order of the differential equation.
(Inherited from PropagationStateElement.)  
InitialConsiderTransitionMatrix 
Gets or sets the optional userspecified initial consider transition matrix. In general this should be left
null and the default value will be used instead. The default initial state takes the form of a
StateDimension by ConsiderDimension zero matrix.
 
InitialStateTransitionMatrix 
Gets or sets the optional userspecified initial state transition matrix. In general this should be left
null and the default value will be used instead. The default initial state takes the form of a
StateDimension by StateDimension identity matrix.
 
IntegrationDynamicMatrix 
Gets a DynamicMatrix which is parameterized on the value of the
StateTransitionMatrix during integration.
This matrix is only valid while the NumericalPropagator is running.
 
IsFrozen 
Gets a value indicating whether this object is frozen. A frozen object cannot be modified and an
ObjectFrozenException will be thrown if an attempt is made to do so.
(Inherited from DefinitionalObject.)  
LinearDimension 
Gets the linear dimension of the StateTransitionMatrix.
 
NumberOfConsiderParameters 
Gets the number of consider parameters that have been added to this StateTransitionMatrix.
 
NumberOfStateParameters 
Gets the number of state parameters and derivatives that have been added to this StateTransitionMatrix.
 
Order 
Gets the order of the differential equation corresponding to this element.
(Overrides PropagationStateElementOrder.)  
StateDimension 
Gets the summed dimension of all of the state parameters.
 
StateParameter 
Gets or sets a parameter which represents the state during propagation. In general,
users should never need to explicitly set this property. It should only be set
when multiple NumericalPropagator objects are running in the same EvaluatorGroup,
such as when elements of a state require additional instances of a NumericalPropagator
inside their implementation in order to produce their values. In such cases, it may
be necessary to distinguish between the state of the exterior propagator and the
state of the interior propagator. In these cases, it is up to the user to ensure
that both the state and all of its elements are configured with the same parameter.
Otherwise, the state will throw an exception when creating its propagator.
(Overrides PropagationStateElementStateParameter.)  
TransitionType 
Gets or sets whether this StateTransitionMatrix is operating in epoch or piecewise mode.
By default this is set to EpochTransition,
which means that the state transition matrix at each time step transforms the state from the epoch state to the state at
that time step.

Name  Description  

AddConsiderParameter 
Adds a consider parameter to the StateTransitionMatrix. Consider parameters can be used when calculating covariance
for a state parameter. The transitions are not actually calculated for a consider parameter, however the values of the consider
parameter do affect those of the state parameters. For example, if you weren't interested in examining how the uncertainty of
the coefficient of drag evolved over time, but were interested in how it's uncertainty affected the uncertainty of the state
parameters, then you would add it as a consider parameter.
 
AddStateParameter  Adds a state parameter to the StateTransitionMatrix. The state parameters added here make up the state represented by the state transition matrix. The stateDerivative of the stateParameter is needed in order to calculate the derivative of the state transition matrix so that it can be integrated.  
CheckForSameDefinition(DefinitionalObject) 
Checks to determine if another instance has the same definition as this instance and
returns if it does. Derived classes MUST override this method and check
all new fields introduced by the derived class for definitional equivalence. It is NOT necessary
to check base class fields because the base class will already have done that. When overriding this method,
you should NOT call the base implementation because it will return for all derivedclass instances.
Derived classes should check the type of other to preserve the symmetric nature of IsSameDefinition(Object).
(Inherited from PropagationStateElement.)  
CheckForSameDefinition(PropagationStateElement) 
Checks to determine if another instance has the same definition as this instance and
returns if it does. Derived classes MUST override this method and check
all new fields introduced by the derived class for definitional equivalence. It is NOT necessary
to check base class fields because the base class will already have done that. When overriding this method,
you should NOT call the base implementation because it will return for all derivedclass instances.
Derived classes should check the type of other to preserve the symmetric nature of IsSameDefinition(Object).
(Overrides PropagationStateElementCheckForSameDefinition(PropagationStateElement).)  
CheckForSameDefinition(StateTransitionMatrix) 
Checks to determine if another instance has the same definition as this instance and
returns if it does. Derived classes MUST override this method and check
all new fields introduced by the derived class for definitional equivalence. It is NOT necessary
to check base class fields because the base class will already have done that. When overriding this method,
you should NOT call the base implementation because it will return for all derivedclass instances.
Derived classes should check the type of other to preserve the symmetric nature of IsSameDefinition(Object).
 
Clone 
Clones this object using the specified context.
(Overrides DefinitionalObjectClone(CopyContext).)  
ComputeCurrentDefinitionHashCode 
Computes a hash code based on the current properties of this object. Derived classes MUST override this
method and compute a hash code that combines: a unique hash code seed, the base implementation result, and
the hash codes of all new fields introduced by the derived class which are used in the
CheckForSameDefinition(DefinitionalObject) method.
(Overrides PropagationStateElementComputeCurrentDefinitionHashCode.)  
EnumerateDependencies 
Enumerates the dependencies of this object by calling
EnumerateT(T) for each object that this object directly depends upon.
Derived classes which contain additional dependencies MUST override this method, call the base
implementation, and enumerate dependencies introduced by the derived class.
(Overrides DefinitionalObjectEnumerateDependencies(DependencyEnumerator).)  
Equals  Determines whether the specified object is equal to the current object. (Inherited from Object.)  
Finalize  Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)  
Freeze 
Freezes this object. Further attempts to modify it will result
in an ObjectFrozenException.
(Inherited from DefinitionalObject.)  
FreezeAggregatedObjects 
Called by Freeze to also freeze any objects that are considered to be a part of this object.
Derived classes which contain additional aggregated objects MUST override this method, call the base
implementation, and freeze aggregated objects introduced by the derived class. The objects that need to be
frozen in this method are frequently created in this object's constructor and are not settable via
properties.
(Overrides DefinitionalObjectFreezeAggregatedObjects.)  
GetConsiderParameter 
Gets the consider parameter at the specified index which has been added to this StateTransitionMatrix.
 
GetConverter 
Gets an instance of an output type which can convert the output of propagation
back into the native type of this state element. This method is also responsible
for configuring the state parameter and the state input indices on any parameterized
geometry types used by this element. Each parameterized geometry type will have
a static configuration method which will allow it to configure itself in a particular
EvaluatorGroup.
(Overrides PropagationStateElementGetConverter(EvaluatorGroup, MotionInt32).)  
GetDefinitionHashCode 
Gets a hash code representing the definition of this object.
(Inherited from DefinitionalObject.)  
GetDerivatives 
This is used by the NumericalPropagatorDefinition to obtain an instance of a state element evaluator
that can compute the derivatives of this element of the state during propagation.
It cannot be used outside of a NumericalPropagator as the geometry for the propagation state
will be unavailable.
(Overrides PropagationStateElementGetDerivatives(EvaluatorGroup).)  
GetHashCode  Serves as the default hash function. (Inherited from Object.)  
GetStateDerivative 
Gets the state derivative at the specified index which has been added to this StateTransitionMatrix.
 
GetStateParameter 
Gets the state parameter at the specified index which has been added to this StateTransitionMatrix.
 
GetStateUpdater  Creates an object that will update the state of the StateTransitionMatrix in between propagation steps, if necessary. If TransitionType is PiecewiseTransition then the matrices produced during propagation represent the transition matrices from the previous time step to their own time step. This means that at the beginning of each propagation step the value of the state transition matrix must be reset to the identity matrix. If TransitionType is EpochTransition then the matrices produced during propagation represent the transition matrices from the epoch to their own time step, and this reset is not necessary.  
GetType  Gets the Type of the current instance. (Inherited from Object.)  
IndexOfConsiderParameter 
Searches for the specified considerParameter and returns the index which
can be used to access it via GetConsiderParameter(Int32) or RemoveConsiderParameterAt(Int32).
 
IndexOfStateDerivative 
Searches for the specified stateDerivative and returns the index which
can be used to access it via GetStateDerivative(Int32) or RemoveStateParameterAt(Int32).
 
IndexOfStateParameter 
Searches for the specified stateParameter and returns the index which
can be used to access it via GetStateParameter(Int32) or RemoveStateParameterAt(Int32).
 
IsSameDefinition 
Determines if this object has the same definition as another object.
(Inherited from DefinitionalObject.)  
MemberwiseClone  Creates a shallow copy of the current Object. (Inherited from Object.)  
PopulateCovarianceCollection 
Transforms an initial covariance matrix forward in time using the given collection of
state transition matrices.
 
RemoveConsiderParameterAt 
Removes the consider parameter at the given index.
 
RemoveStateParameterAt 
Removes the state parameter at the given index, as well as its derivative.
 
ThrowIfFrozen 
Throws ObjectFrozenException if this object IsFrozen.
This method should be called from any method or property that modifies this object.
(Inherited from DefinitionalObject.)  
ToString  Returns a string that represents the current object. (Inherited from Object.) 
If consider parameters are used, then this class represents information in the following form:
If the cumulative dimension of the state elements is N, and the cumulative dimension of the consider parameters is M, then Φ is an ordinary state transition matrix: an NxN matrix equal to the partials of the state at time t_{j} with respect to the state at time t_{i}. Θ is an NxM matrix equal to the partials of the state at time t_{j} with respect to the consider parameters at time t_{i}, and the zero and identity matrices are size MxN and MxM, respectively. The complete consider covariance matrix is a square matrix with a dimension of N+M.