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java.lang.Objectorg.apache.hama.util.RandomVariable
public class RandomVariable
The RandomVaraibale Class provides static methods for generating random numbers.
Constructor Summary | |
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RandomVariable()
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Method Summary | |
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static double |
beta(double a,
double b)
Generate a random number from a beta random variable. |
static double |
cauchy(double mu,
double sigma)
Generate a random number from a Cauchy random variable (Mean = Inf, and Variance = Inf). |
static double |
chi2(int n)
Generate a random number from a Chi-2 random variable. |
static double |
dirac(double[] values,
double[] prob)
Generate a random number from a discrete random variable. |
static double |
exponential(double lambda)
Generate a random number from an exponantial random variable (Mean = 1/lambda, variance = 1/lambda^2). |
static double |
logNormal(double mu,
double sigma)
Generate a random number from a LogNormal random variable. |
static double |
normal(double mu,
double sigma)
Generate a random number from a Gaussian (Normal) random variable. |
static double |
rand()
Generate a random number between 0 and 1. |
static int |
randInt(int i0,
int i1)
Generate a random integer. |
static java.lang.String |
randString(java.lang.String prefix,
int length)
Generate a random string using the specified prefix and a fixed length. |
static double |
triangular(double min,
double max)
Generate a random number from a symetric triangular random variable. |
static double |
triangular(double min,
double med,
double max)
Generate a random number from a non-symetric triangular random variable. |
static double |
uniform(double min,
double max)
Generate a random number from a uniform random variable. |
static double |
weibull(double lambda,
double c)
Generate a random number from a Weibull random variable. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public RandomVariable()
Method Detail |
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public static double rand()
public static int randInt(int i0, int i1)
i0
- min of the random variable.i1
- max of the random variable.
public static java.lang.String randString(java.lang.String prefix, int length)
prefix
- the specified string prefix.length
- the length of the string to be appended.
public static double uniform(double min, double max)
min
- min of the random variable.max
- max of the random variable.
public static double dirac(double[] values, double[] prob)
values
- discrete values.prob
- probability of each value.
public static double normal(double mu, double sigma)
mu
- mean of the random variable.sigma
- standard deviation of the random variable.
public static double chi2(int n)
n
- degrees of freedom of the chi2 random variable.
public static double logNormal(double mu, double sigma)
mu
- mean of the Normal random variable.sigma
- standard deviation of the Normal random variable.
public static double exponential(double lambda)
lambda
- parmaeter of the exponential random variable.
public static double triangular(double min, double max)
min
- min of the random variable.max
- max of the random variable.
public static double triangular(double min, double med, double max)
min
- min of the random variable.med
- value of the random variable with max density.max
- max of the random variable.
public static double beta(double a, double b)
a
- first parameter of the Beta random variable.b
- second parameter of the Beta random variable.
public static double cauchy(double mu, double sigma)
mu
- median of the Weibull random variablesigma
- second parameter of the Cauchy random variable.
public static double weibull(double lambda, double c)
lambda
- first parameter of the Weibull random variable.c
- second parameter of the Weibull random variable.
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