Package de.uka.ipd.sdq.simucomframework

Class SimuComDefaultRandomNumberGenerator

  • All Implemented Interfaces:
    de.uka.ipd.sdq.probfunction.math.IRandomGenerator
    public class SimuComDefaultRandomNumberGenerator
extends Object
implements de.uka.ipd.sdq.probfunction.math.IRandomGenerator
    SimuComDefaultRandomNumberGenerator generates random numbers in a separate thread. SimuComDefaultRandomNumberGenerator currently implements the interface for random numbers needed by the prob function package. However, internally it relies on a random stream implementing the RandomStream interface from JSS. SimuComDefaultRandomNumberGenerator implements RandomStream as the functions like LogNormDistFunction and NormDistFunction in package de.uka.ipd.sdq.simucomframework.variables.functions. This class is optimized for multi-cores, thus speeding up simulation significantly for at least two cores. Here everything related to random numbers in SimuCom should be then localised, especially seed initialisation and the multi-threading stuff (which was - as always - deadlock prone while implementing). Also it locates the dependency to the [0..1] random number generator to a single place in the source (remember this needs to be changed to get away from GPL code...).

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void dispose()  
      void nextArrayOfDouble​(double[] u, int start, int n)
      Generates n (pseudo)random numbers from the uniform distribution and stores them into the array u starting at index start.
      void nextArrayOfInt​(int i, int j, int[] u, int start, int n)
      Generates n (pseudo)random numbers from the discrete uniform distribution over the integers {i, i + 1,..., j}, using this stream and stores the result in the array u starting at index start.
      double nextDouble()
      Returns a (pseudo)random number from the uniform distribution over the interval (0, 1), using this stream, after advancing its state by one step.
      int nextInt​(int i, int j)
      Returns a (pseudo)random number from the discrete uniform distribution over the integers {i, i + 1,..., j}, using this stream.
      double random()
      Returns a (pseudo)random number from the uniform distribution over the interval (0, 1), using this stream, after advancing its state by one step.
      void resetNextSubstream()
      does nothing because this implementation does not support any substreams
      void resetStartStream()
      does nothing because this implementation does not support any substreams
      void resetStartSubstream()
      does nothing because this implementation does not support any substreams

    • Constructor Detail

      • SimuComDefaultRandomNumberGenerator

        public SimuComDefaultRandomNumberGenerator​(long[] randomSeed)

    • Method Detail

      • random

        public double random()
        Returns a (pseudo)random number from the uniform distribution over the interval (0, 1), using this stream, after advancing its state by one step. The generators programmed in SSJ never return the values 0 or 1. This method takes a previously generated random number from the asynchronously running generator thread.
        Specified by:
        random in interface de.uka.ipd.sdq.probfunction.math.IRandomGenerator

      • dispose

        public void dispose()
        Specified by:
        dispose in interface de.uka.ipd.sdq.probfunction.math.IRandomGenerator

      • nextArrayOfDouble

        public void nextArrayOfDouble​(double[] u,
                              int start,
                              int n)
        Generates n (pseudo)random numbers from the uniform distribution and stores them into the array u starting at index start. (doc from RandomStream)
        Parameters:
        u - - array that will contain the generated uniforms
        start - - starting index, in the array u, to write uniforms from
        n - - number of uniforms to generate

      • nextArrayOfInt

        public void nextArrayOfInt​(int i,
                           int j,
                           int[] u,
                           int start,
                           int n)
        Generates n (pseudo)random numbers from the discrete uniform distribution over the integers {i, i + 1,..., j}, using this stream and stores the result in the array u starting at index start. (Calls nextInt n times.) (doc from RandomStream
        Parameters:
        i - - smallest integer that can be generated
        j - - greatest integer that can be generated
        u - - array that will contain the generated values
        start - - starting index, in the array u, to write integers from
        n - - number of values being generated

      • nextDouble

        public double nextDouble()
        Returns a (pseudo)random number from the uniform distribution over the interval (0, 1), using this stream, after advancing its state by one step. The generators programmed in SSJ never return the values 0 or 1. Calls random() which takes a previously generated random number from the asynchronously running generator thread.

      • nextInt

        public int nextInt​(int i,
                   int j)
        Returns a (pseudo)random number from the discrete uniform distribution over the integers {i, i + 1,..., j}, using this stream. (Calls nextDouble once.) Copied from RandomStreamBase.
        Parameters:
        i - - smallest integer that can be generated
        j - - greatest integer that can be generated

      • resetNextSubstream

        public void resetNextSubstream()
        does nothing because this implementation does not support any substreams

      • resetStartStream

        public void resetStartStream()
        does nothing because this implementation does not support any substreams

      • resetStartSubstream

        public void resetStartSubstream()
        does nothing because this implementation does not support any substreams