jas.random
Class RandomGenerator

java.lang.Object
  jas.random.RandomGenerator

public class RandomGenerator
extends java.lang.Object

This class is a repository for random number generators. It is able to generate random numbers from many distribution through static methods.

All generators are synchronized with the same random seed. It guarantees the repetibility of experiments.

The first the time is asked a number from a particular distribution RandomGenerator creates a new instance and reuse it at the next calls.

Title: JAS

Description: Java Agent-based Simulation library

Copyright (C) 2002 Michele Sonnessa

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.

Author:

Michele Sonnessa

Constructor Summary

RandomGenerator()
Default constructor.

RandomGenerator(int seed)
This constructor creates a MersenneTwister raw generator with the given seed.

Method Summary

double	getBeta(double alpha, double beta) Generate a random sample from the Beta distribution with given parameters.
int	getBinomial(int n, double p) Generate a random sample from the Binomial distribution with given parameters.
double	getBreitWigner(double mean, double gamma, double cut) Generate a random sample from the BreitWigner distribution with given parameters.
double	getBreitWignerMeanSquare(double mean, double gamma, double cut) Generate a random sample from the BreitWignerMeanSquare distribution with given parameters.
double	getBurr1(double r, int nr) Generate a random sample from the Burr1 distribution with given parameters.
double	getBurr2(double r, double k, int nr) Generate a random sample from the Burr2 distribution with given parameters.
double	getCauchy() Generate a random sample from the Cauchy distribution with given parameters.
double	getChiSquare(double freedom) Generate a random sample from the ChiSquare distribution with given parameters.
double	getDblFromTo(double from, double to) Generate a random double within the exclusive interval (from, to).
double	getErlang(double variance, double mean) Generate a random sample from the Erlang distribution with given parameters.
double	getExponential(double lambda) Generate a random sample from the Exponential distribution with given parameters.
double	getExponentialPower(double tau) Generate a random sample from the ExponentialPower distribution with given parameters.
float	getFloatFromTo(float from, float to) Generate a random float within the exclusive interval (from, to).
double	getGamma(double alpha, double lambda) Generate a random sample from the Gamma distribution with given parameters.
int	getGeometric(double p) Generate a random sample from the Geometric distribution with given parameters.
double	getHyperbolic(double alpha, double beta) Generate a random sample from the Hyperbolic distribution with given parameters.
int	getHyperGeometric(int N, int s, int n) Generate a random sample from the HyperGeometric distribution with given parameters.
int	getIntFromTo(int from, int to) Generate a random integer within the inclusive interval [from, to].
double	getLambda(double l3, double l4) Generate a random sample from the Lambda distribution with given parameters.
double	getLaplace() Generate a random sample from the Laplace distribution with given parameters.
double	getLogarithmic(double p) Generate a random sample from the Logarithmic distribution with given parameters.
double	getLogistic() Generate a random sample from the Logistic distribution with given parameters.
long	getLongFromTo(long from, long to) Generate a random long within the inclusive interval [from, to].
int	getNegativeBinomial(int n, double p) Generate a random sample from the NegativeBinomial distribution with given parameters.
double	getNormal(double mean, double standardDeviation) Generate a random sample from the Normal distribution with given parameters.
int	getPoisson(double mean) Generate a random sample from the Poisson distribution with given parameters.
double	getPowLaw(double alpha, double cut) Generate a random sample from the PowLaw distribution with given parameters.
cern.jet.random.engine.RandomEngine	getRandomEngine() Return the current raw generator.
int	getSeed() Change the seed for the current raw generator.
double	getTriangular() Generate a random sample from the Triangular distribution with given parameters.
double	getVonMises(double freedom) Generate a random sample from the VonMises distribution with given parameters.
double	getWeibull(double alpha, double beta) Generate a random sample from the Weibull distribution with given parameters.
int	getZeta(double ro, double pk) Generate a random sample from the Zeta distribution with given parameters.
int	getZipfInt(double z) Generate a random sample from the ZipfInt distribution with given parameters.
void	setSeed(int newSeed) Change the seed for the current raw generator.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RandomGenerator

public RandomGenerator()

Default constructor. Creates a MersenneTwister raw generator with a random seed. It uses System.currentTimeMillis() as seed.

RandomGenerator

public RandomGenerator(int seed)

This constructor creates a MersenneTwister raw generator with the given seed.

Parameters:

seed - The seed for random numbers.

Method Detail

getBeta

public double getBeta(double alpha,
                      double beta)

Generate a random sample from the Beta distribution with given parameters. See cern.jet.random.Beta API for more details.

Parameters:

alpha - A well known distribution parameters.

beta - A well known distribution parameters.

Returns:

The requested random number.

getBinomial

public int getBinomial(int n,
                       double p)

Generate a random sample from the Binomial distribution with given parameters. See cern.jet.random.Binomial API for more details.

Parameters:

n - A well known distribution parameters.

p - A well known distribution parameters.

Returns:

The requested random number.

getBreitWigner

public double getBreitWigner(double mean,
                             double gamma,
                             double cut)

Generate a random sample from the BreitWigner distribution with given parameters. See cern.jet.random.BreitWigner API for more details.

Parameters:

mean - A well known distribution parameters.

gamma - A well known distribution parameters.

cut - A well known distribution parameters.

Returns:

The requested random number.

getBreitWignerMeanSquare

public double getBreitWignerMeanSquare(double mean,
                                       double gamma,
                                       double cut)

Generate a random sample from the BreitWignerMeanSquare distribution with given parameters. See cern.jet.random.BreitWignerMeanSquare API for more details.

Parameters:

mean - A well known distribution parameters.

gamma - A well known distribution parameters.

cut - A well known distribution parameters.

Returns:

The requested random number.

getBurr1

public double getBurr1(double r,
                       int nr)

Generate a random sample from the Burr1 distribution with given parameters. See cern.jet.random.Distributions API for more details.

Parameters:

r - A well known distribution parameters.

nr - A well known distribution parameters.

Returns:

The requested random number.

getBurr2

public double getBurr2(double r,
                       double k,
                       int nr)

Generate a random sample from the Burr2 distribution with given parameters. See cern.jet.random.Distributions API for more details.

Parameters:

r - A well known distribution parameters.

k - A well known distribution parameters.

nr - A well known distribution parameters.

Returns:

The requested random number.

getCauchy

public double getCauchy()

Generate a random sample from the Cauchy distribution with given parameters. See cern.jet.random.Distributions API for more details.

Returns:

The requested random number.

getChiSquare

public double getChiSquare(double freedom)

Generate a random sample from the ChiSquare distribution with given parameters. See cern.jet.random.ChiSquare API for more details.

Parameters:

freedom - A well known distribution parameters.

Returns:

The requested random number.

getDblFromTo

public double getDblFromTo(double from,
                           double to)

Generate a random double within the exclusive interval (from, to).

Parameters:

from - The lower exclusive bound.

to - The upper exclusive bound.

Returns:

The requested random number.

getErlang

public double getErlang(double variance,
                        double mean)

Generate a random sample from the Erlang distribution with given parameters. See cern.jet.random.Distributions API for more details.

Parameters:

variance - A well known distribution parameters.

mean - A well known distribution parameters.

Returns:

The requested random number.

getExponential

public double getExponential(double lambda)

Generate a random sample from the Exponential distribution with given parameters. See cern.jet.random.Exponential API for more details.

Parameters:

lambda - A well known distribution parameters.

Returns:

The requested random number.

getExponentialPower

public double getExponentialPower(double tau)

Generate a random sample from the ExponentialPower distribution with given parameters. See cern.jet.random.ExponentialPower API for more details.

Parameters:

tau - A well known distribution parameters.

Returns:

The requested random number.

getFloatFromTo

public float getFloatFromTo(float from,
                            float to)

Generate a random float within the exclusive interval (from, to).

Parameters:

from - The lower exclusive bound.

to - The upper exclusive bound.

Returns:

The requested random number.

getGamma

public double getGamma(double alpha,
                       double lambda)

Generate a random sample from the Gamma distribution with given parameters. See cern.jet.random.Gamma API for more details.

Parameters:

alpha - A well known distribution parameters.

lambda - A well known distribution parameters.

Returns:

The requested random number.

getGeometric

public int getGeometric(double p)

Generate a random sample from the Geometric distribution with given parameters. See cern.jet.random.Distributions API for more details.

Parameters:

p - A well known distribution parameters.

Returns:

The requested random number.

getHyperbolic

public double getHyperbolic(double alpha,
                            double beta)

Generate a random sample from the Hyperbolic distribution with given parameters. See cern.jet.random.Hyperbolic API for more details.

Parameters:

alpha - A well known distribution parameters.

beta - A well known distribution parameters.

Returns:

The requested random number.

getHyperGeometric

public int getHyperGeometric(int N,
                             int s,
                             int n)

Generate a random sample from the HyperGeometric distribution with given parameters. See cern.jet.random.HyperGeometric API for more details.

Parameters:

N - A well known distribution parameters.

s - A well known distribution parameters.

n - A well known distribution parameters.

Returns:

The requested random number.

getIntFromTo

public int getIntFromTo(int from,
                        int to)

Generate a random integer within the inclusive interval [from, to].

Parameters:

from - The lower inclusive bound.

to - The upper inclusive bound.

Returns:

The requested random number.

getLambda

public double getLambda(double l3,
                        double l4)

Generate a random sample from the Lambda distribution with given parameters. See cern.jet.random.Distributions API for more details.

Parameters:

l3 - A well known distribution parameters.

l4 - A well known distribution parameters.

Returns:

The requested random number.

getLaplace

public double getLaplace()

Generate a random sample from the Laplace distribution with given parameters. See cern.jet.random.Distributions API for more details.

Returns:

The requested random number.

getLogarithmic

public double getLogarithmic(double p)

Generate a random sample from the Logarithmic distribution with given parameters. See cern.jet.random.Logarithmic API for more details.

Parameters:

p - A well known distribution parameters.

Returns:

The requested random number.

getLogistic

public double getLogistic()

Generate a random sample from the Logistic distribution with given parameters. See cern.jet.random.Distributions API for more details.

Returns:

The requested random number.

getLongFromTo

public long getLongFromTo(long from,
                          long to)

Generate a random long within the inclusive interval [from, to].

Parameters:

from - The lower inclusive bound.

to - The upper inclusive bound.

Returns:

The requested random number.

getNegativeBinomial

public int getNegativeBinomial(int n,
                               double p)

Generate a random sample from the NegativeBinomial distribution with given parameters. See cern.jet.random.NegativeBinomial API for more details.

Parameters:

n - A well known distribution parameters.

p - A well known distribution parameters.

Returns:

The requested random number.

getNormal

public double getNormal(double mean,
                        double standardDeviation)

Generate a random sample from the Normal distribution with given parameters. See cern.jet.random.Normal API for more details.

Parameters:

mean - A well known distribution parameters.

standardDeviation - A well known distribution parameters.

Returns:

The requested random number.

getPoisson

public int getPoisson(double mean)

Generate a random sample from the Poisson distribution with given parameters. See cern.jet.random.Poisson API for more details.

Parameters:

mean - A well known distribution parameters.

Returns:

The requested random number.

getPowLaw

public double getPowLaw(double alpha,
                        double cut)

Generate a random sample from the PowLaw distribution with given parameters. See cern.jet.random.Distributions API for more details.

Parameters:

alpha - A well known distribution parameters.

cut - A well known distribution parameters.

Returns:

The requested random number.

getRandomEngine

public cern.jet.random.engine.RandomEngine getRandomEngine()

Return the current raw generator.

Returns:

the random generator for raw numbers used by each distribution.

getSeed

public int getSeed()

Change the seed for the current raw generator. WARNING: Changing the seeds cause the construction of a new instance of MersenneTwister.

Parameters:

newSeed - The new seed number.

getTriangular

public double getTriangular()

Generate a random sample from the Triangular distribution with given parameters. See cern.jet.random.Distributions API for more details.

Returns:

The requested random number.

getVonMises

public double getVonMises(double freedom)

Generate a random sample from the VonMises distribution with given parameters. See cern.jet.random.VonMises API for more details.

Parameters:

freedom - A well known distribution parameters.

Returns:

The requested random number.

getWeibull

public double getWeibull(double alpha,
                         double beta)

Generate a random sample from the Weibull distribution with given parameters. See cern.jet.random.Distributions API for more details.

Parameters:

alpha - A well known distribution parameters.

beta - A well known distribution parameters.

Returns:

The requested random number.

getZeta

public int getZeta(double ro,
                   double pk)

Generate a random sample from the Zeta distribution with given parameters. See cern.jet.random.Zeta API for more details.

Parameters:

ro - A well known distribution parameters.

pk - A well known distribution parameters.

Returns:

The requested random number.

getZipfInt

public int getZipfInt(double z)

Generate a random sample from the ZipfInt distribution with given parameters. See cern.jet.random.Distributions API for more details.

Parameters:

z - A well known distribution parameters.

Returns:

The requested random number.

setSeed

public void setSeed(int newSeed)

Change the seed for the current raw generator. WARNING: Changing the seeds cause the construction of a new instance of MersenneTwister.

Parameters:

newSeed - The new seed number.