Package jline.lang.processes

Class Erlang

java.lang.Object
jline.lang.processes.Distribution
jline.lang.processes.ContinuousDistribution
jline.lang.processes.Markovian
jline.lang.processes.Erlang
All Implemented Interfaces:
Serializable, Copyable
public class Erlang extends Markovian implements Serializable
An Erlang-n distribution with n phases.
See Also:

  • Constructor Details

    • Erlang

      public Erlang(double phaseRate, int n)
      Creates an Erlang distribution with the specified phase rate and number of phases.
      Parameters:
      phaseRate - the rate parameter for each phase
      n - the number of phases

  • Method Details

    • fitMeanAndOrder

      public static Erlang fitMeanAndOrder(double mean, long numPhases)
      Creates an Erlang distribution fitted to the specified mean and number of phases.
      Parameters:
      mean - the desired mean value
      numPhases - the number of phases
      Returns:
      an Erlang distribution with the specified characteristics

    • fitMeanAndSCV

      public static Erlang fitMeanAndSCV(double mean, double SCV)
      Creates an Erlang distribution fitted to the specified mean and squared coefficient of variation. An Erlang of order r has SCV = 1/r, so no Erlang has SCV > 1 and the request is refused rather than answered with the 1-phase Erlang, which is an exponential and therefore a distribution the caller did not ask for. Port of the guard in MATLAB Erlang.fitMeanAndSCV.
      Parameters:
      mean - the desired mean value
      SCV - the desired squared coefficient of variation, which must be at most 1
      Returns:
      an Erlang distribution with the specified characteristics
      Throws:
      IllegalArgumentException - if the SCV exceeds 1

    • fitMeanAndStdDev

      public static Erlang fitMeanAndStdDev(double mean, double stdDev)
      Creates an Erlang distribution fitted to the specified mean and standard deviation. The SCV is the squared coefficient of VARIATION, (stdDev/mean)^2. This read mean/stdDev^2, which is not dimensionless and is not the SCV of anything: at mean = 2 and stdDev = 2 (an exponential, SCV 1) it asked for SCV 0.5 and returned a 2-phase Erlang. JLINE-only entry point, with no MATLAB counterpart and no caller in the tree, so the defect was latent.
      Parameters:
      mean - the desired mean value
      stdDev - the desired standard deviation
      Returns:
      an Erlang distribution with the specified characteristics

    • evalCDF

      public double evalCDF(double t)
      Evaluates the cumulative distribution function at the given point.
      Overrides:
      evalCDF in class Markovian
      Parameters:
      t - the point at which to evaluate the CDF
      Returns:
      the CDF value at point t

    • evalLST

      public double evalLST(double s)
      Evaluates the Laplace-Stieltjes transform at the given point.
      Overrides:
      evalLST in class Markovian
      Parameters:
      s - the transform variable
      Returns:
      the LST value (α/(α+s))^r

    • getMean

      public double getMean()
      Gets the mean of this Erlang distribution.
      Overrides:
      getMean in class Markovian
      Returns:
      the mean value (r/α)

    • getRate

      public double getRate()
      Gets the rate of this Erlang distribution.
      Overrides:
      getRate in class Markovian
      Returns:
      the rate (α/r)

    • getSCV

      public double getSCV()
      Gets the squared coefficient of variation.
      Overrides:
      getSCV in class Markovian
      Returns:
      the SCV (1/r)

    • getSkewness

      public double getSkewness()
      Gets the skewness of this Erlang distribution.
      Overrides:
      getSkewness in class Markovian
      Returns:
      the skewness (2/√r)

    • getVar

      public double getVar()
      Gets the variance of this Erlang distribution.
      Overrides:
      getVar in class Markovian
      Returns:
      the variance (r/α²)

    • sample

      public double[] sample(int n, Random random)
      Description copied from class: Distribution
      Generates random samples from this distribution using the specified random generator.
      Overrides:
      sample in class Markovian
      Parameters:
      n - the number of samples to generate
      random - the random number generator to use
      Returns:
      array of random samples

    • sample

      public double[] sample(int n)
      Description copied from class: Distribution
      Generates random samples from this distribution using default random generator.
      Overrides:
      sample in class Markovian
      Parameters:
      n - the number of samples to generate
      Returns:
      array of random samples

    • mean

      public double mean()
      Property alias for getMean
      Overrides:
      mean in class Markovian

    • rate

      public double rate()
      Property alias for getRate
      Overrides:
      rate in class Markovian

    • scv

      public double scv()
      Property alias for getSCV
      Overrides:
      scv in class Markovian

    • skewness

      public double skewness()
      Property alias for getSkewness
      Overrides:
      skewness in class Markovian

    • var

      public double var()
      Property alias for getVar
      Overrides:
      var in class Markovian