SSJ  3.3.1
Stochastic Simulation in Java
Public Member Functions | Protected Member Functions | Protected Attributes | List of all members
MultivariateStochasticProcess Class Referenceabstract

This class is a multivariate version of StochasticProcess where the process evolves in the \(c\)-dimensional real space. More...

Inheritance diagram for MultivariateStochasticProcess:
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Collaboration diagram for MultivariateStochasticProcess:
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Public Member Functions

abstract double [] generatePath ()
 Generates, returns, and saves the sample path. More...
 
void getSubpath (double[] subpath, int[] pathIndices)
 Returns in subpath the values of the process at a subset of the observation times, specified as the times \(t_j\) whose indices. More...
 
void setObservationTimes (double[] t, int d)
 Sets the observation times of the process to a copy of t, with. More...
 
void getObservation (int j, double[] obs)
 Returns \(\mathbf{X}(t_j)\) in the \(c\)-dimensional vector obs.
 
double getObservation (int j, int i)
 Returns \(X_i(t_j)\) from the current sample path.
 
abstract void nextObservationVector (double[] obs)
 Generates and returns in obs the next observation. More...
 
void getCurrentObservation (double[] obs)
 Returns the value of the last generated observation. More...
 
double [] getX0 (double[] x0)
 Returns in x0 the initial value \(\mathbf{X}(t_0)\) for this process.
 
int getDimension ()
 Returns the dimension of \(\mathbf{X}\).
 
- Public Member Functions inherited from StochasticProcess
void setObservationTimes (double[] T, int d)
 Sets the observation times of the process to a copy of T, with. More...
 
void setObservationTimes (double delta, int d)
 Sets equidistant observation times at \(t_j = j\delta\), for. More...
 
double [] getObservationTimes ()
 Returns a reference to the array that contains the observation times. More...
 
int getNumObservationTimes ()
 Returns the number \(d\) of observation times, excluding the time \(t_0\).
 
abstract double [] generatePath ()
 Generates, returns, and saves the sample path \(\{X(t_0), X(t_1), \dots, X(t_d)\}\). More...
 
double [] generatePath (RandomStream stream)
 Same as generatePath(), but first resets the stream to stream.
 
double [] getPath ()
 Returns a reference to the last generated sample path \(\{X(t_0), ... , X(t_d)\}\). More...
 
void getSubpath (double[] subpath, int[] pathIndices)
 Returns in subpath the values of the process at a subset of the observation times, specified as the times \(t_j\) whose indices. More...
 
double getObservation (int j)
 Returns \(X(t_j)\) from the current sample path. More...
 
void resetStartProcess ()
 Resets the observation counter to its initial value \(j=0\), so that the current observation \(X(t_j)\) becomes \(X(t_0)\). More...
 
boolean hasNextObservation ()
 Returns true if \(j<d\), where \(j\) is the number of observations of the current sample path generated since the last call to resetStartProcess. More...
 
double nextObservation ()
 Generates and returns the next observation \(X(t_j)\) of the stochastic process. More...
 
int getCurrentObservationIndex ()
 Returns the value of the index \(j\) corresponding to the time. More...
 
double getCurrentObservation ()
 Returns the value of the last generated observation \(X(t_j)\).
 
double getX0 ()
 Returns the initial value \(X(t_0)\) for this process.
 
void setX0 (double s0)
 Sets the initial value \(X(t_0)\) for this process to s0, and reinitializes.
 
abstract void setStream (RandomStream stream)
 Resets the random stream of the underlying generator to stream.
 
abstract RandomStream getStream ()
 Returns the random stream of the underlying generator.
 
int [] getArrayMappingCounterToIndex ()
 Returns a reference to an array that maps an integer \(k\) to \(i_k\), the index of the observation \(S(t_{i_k})\) corresponding to the \(k\)-th observation to be generated for a sample path of this process. More...
 

Protected Member Functions

void init ()
 
void createPath ()
 
- Protected Member Functions inherited from StochasticProcess
void init ()
 

Protected Attributes

double [] x0
 
int c = 1
 
- Protected Attributes inherited from StochasticProcess
boolean observationTimesSet = false
 
double x0 = 0.0
 
int d = -1
 
int observationIndex = 0
 
int observationCounter = 0
 
double [] t
 
double [] path
 
int [] observationIndexFromCounter
 

Detailed Description

This class is a multivariate version of StochasticProcess where the process evolves in the \(c\)-dimensional real space.

It is an abstract (base) class for a multivariate stochastic process \(\{\mathbf{X}(t) = (X_1(t),…,X_c(t)), t \geq0 \}\), sampled (or observed) at a finite number of time points, \(0 = t_0 < t_1 < \cdots< t_d\). The observation times can be specified by setObservationTimes. The method generatePath generates \(\mathbf{X}(t_1),…,\mathbf{X}(t_d)\) and memorizes them in a (one-dimensional) vector, which can be recovered by getPath. The element \(cj+i-1\) of this vector contains \(X_i(t_j)\), for \(j=0,…,d\) and

\(i=1,…,c\). Alternatively, in some cases, the observations \(\mathbf{X}(t_j)\) can be generated sequentially, one at a time, by invoking resetStartProcess first, and then nextObservationVector repeatedly.

Member Function Documentation

◆ generatePath()

abstract double [] generatePath ( )
abstract

Generates, returns, and saves the sample path.

\(\{\mathbf{X}(t_0), \mathbf{X}(t_1), …, \mathbf{X}(t_d)\}\), which can then be accessed via getPath, getSubpath, or getObservation. The generation method depends on the process type. If path[] denotes the returned array, then path[cj + i-1] contains \(X_i(t_j)\) for \(j=0,…,d\) and \(i=1,…,c\).

◆ getCurrentObservation()

void getCurrentObservation ( double []  obs)

Returns the value of the last generated observation.

\(\mathbf{X}(t_j)\).

◆ getSubpath()

void getSubpath ( double []  subpath,
int []  pathIndices 
)

Returns in subpath the values of the process at a subset of the observation times, specified as the times \(t_j\) whose indices.

\(j\) are in the array pathIndices. The size of pathIndices should be at least as much as that of subpath.

◆ nextObservationVector()

abstract void nextObservationVector ( double []  obs)
abstract

Generates and returns in obs the next observation.

\(\mathbf{X}(t_j)\).

◆ setObservationTimes()

void setObservationTimes ( double []  t,
int  d 
)

Sets the observation times of the process to a copy of t, with.

\(t_0 = \mathtt{t[0]}\) and \(t_d = \mathtt{t[d]}\). The size of t must be \(d+1\).


The documentation for this class was generated from the following file: