Package jline.lang.processes

Class Expolynomial

java.lang.Object
jline.lang.processes.Distribution
jline.lang.processes.ContinuousDistribution
jline.lang.processes.Expolynomial
All Implemented Interfaces:
Serializable, Copyable
public class Expolynomial extends ContinuousDistribution implements Serializable
Expolynomial distribution with density f(x) = sum ci * x^ai * exp(-li*x).

Represents an expolynomial density over a bounded domain [eft, lft], matching the Sirio/ORIS GEN expolynomial format. The density is carried as a Sirio expression string rather than as numeric parameters, so it is opaque to this class: the class stores and transports it verbatim.

The parameter slots mirror the MATLAB reference implementation (matlab/src/lang/processes/Expolynomial.m):

  • param 1 - density, the Sirio density expression string
  • param 2 - eft, the earliest firing time (lower bound of support)
  • param 3 - lft, the latest firing time (upper bound of support, possibly Double.POSITIVE_INFINITY)

Moments. As in MATLAB and in the Python-native implementation, the moments of an expolynomial density are not obtained by numerical integration: getMean(), getSCV(), getSkewness(), evalCDF(double), evalLST(double) and sample(int, Random) all return NaN. The distribution is therefore a transport-only type in the lang layer: it carries the density to engines that can interpret it (Sirio/ORIS GEN), and every moment-based solver sees NaN rather than a silently wrong value.

Support. Unlike MATLAB, which passes a NaN placeholder triple to the superclass constructor, the support is reported here as the pair (eft, lft), matching the getSupport of the Python-native implementation.

See Also:

  • Constructor Details

    • Expolynomial

      public Expolynomial(String density, double eft, double lft)
      Creates an expolynomial distribution.
      Parameters:
      density - density expression string in Sirio format
      eft - earliest firing time (lower bound of support)
      lft - latest firing time (upper bound of support, may be Double.POSITIVE_INFINITY)

  • Method Details

    • getDensity

      public String getDensity()
      Returns the density expression string in Sirio format.

    • getEft

      public double getEft()
      Returns the earliest firing time, i.e. the lower bound of the support.

    • getLft

      public double getLft()
      Returns the latest firing time, i.e. the upper bound of the support. May be Double.POSITIVE_INFINITY for an unbounded density.

    • getMean

      public double getMean()
      Returns NaN: the mean is not obtained by numerical integration.
      Specified by:
      getMean in class Distribution
      Returns:
      the mean value

    • getSCV

      public double getSCV()
      Returns NaN: the SCV is not obtained by numerical integration.
      Specified by:
      getSCV in class Distribution
      Returns:
      the squared coefficient of variation

    • getSkewness

      public double getSkewness()
      Returns NaN: the skewness is not obtained by numerical integration.
      Specified by:
      getSkewness in class Distribution
      Returns:
      the skewness value

    • evalCDF

      public double evalCDF(double t)
      Returns NaN: the CDF of a Sirio density expression is not evaluated here.
      Specified by:
      evalCDF in class Distribution
      Parameters:
      t - the point at which to evaluate the CDF
      Returns:
      the CDF value at point t

    • evalLST

      public double evalLST(double s)
      Returns NaN: the LST of a Sirio density expression is not evaluated here.
      Specified by:
      evalLST in class ContinuousDistribution
      Parameters:
      s - the Laplace domain variable
      Returns:
      the LST value at s

    • getProcess

      public MatrixCell getProcess()
      Returns the numeric part of the process representation, {eft, lft}, as two singleton matrices. The density expression is a string and hence cannot be held in a MatrixCell; obtain it with getDensity().
      Specified by:
      getProcess in class ContinuousDistribution
      Returns:
      MatrixCell with distribution-specific parameters

    • sample

      public double[] sample(int n, Random random)
      Returns an array of n NaNs: sampling a Sirio density expression is not supported.
      Specified by:
      sample in class Distribution
      Parameters:
      n - the number of samples to generate
      random - the random number generator to use
      Returns:
      array of random samples

    • toString

      public String toString()
      Overrides:
      toString in class Object