Package cc.mallet.util

Class Randoms

  • All Implemented Interfaces:
    java.io.Serializable
    public class Randoms
extends java.util.Random
    See Also:
    Serialized Form

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static double ONE_OVER_E  

    • Constructor Summary

      Constructors 
      Constructor Description
      Randoms()  
      Randoms​(int seed)  

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method Description
      java.util.Random asJavaRandom()
      Deprecated.
      static void main​(java.lang.String[] args)  
      double nextBeta​(double alpha, double beta)
      Return a random double drawn from a Beta distribution with mean a/(a+b) and variance ab/((a+b+1)(a+b)^2).
      java.util.BitSet nextBitSet​(int size, double p)
      Return a random BitSet with "size" bits, each having probability p of being true.
      boolean nextBoolean()
      Return a random boolean, equally likely to be true or false.
      boolean nextBoolean​(double p)
      Return a random boolean, with probability p of being true.
      double nextChiSq()
      Return a random double drawn from an Chi-squarted distribution with mean 1 and variance 2.
      double nextChiSq​(int df)
      Return a random double drawn from an Chi-squared distribution with mean df and variance 2*df.
      double nextChiSq​(int df, double lambda)
      Return a random double drawn from an Chi-squared distribution with mean df+lambda and variance 2*df.
      int nextDiscrete​(double[] a)
      Draw a single sample from multinomial "a".
      int nextDiscrete​(double[] a, double sum)
      draw a single sample from (unnormalized) multinomial "a", with normalizing factor "sum".
      double nextExp()
      Return a random double drawn from an Exponential distribution with mean 1 and variance 1.
      double nextExp​(double beta)
      Return a random double drawn from an Exponential distribution with mean beta and variance beta^2.
      double nextExp​(double beta, double lambda)
      Return a random double drawn from an Exponential distribution with mean beta+lambda and variance beta^2.
      double nextGamma()
      Return a random double drawn from a Gamma distribution with mean 1.0 and variance 1.0.
      double nextGamma​(double alpha)
      Return a random double drawn from a Gamma distribution with mean alpha and variance 1.0.
      double nextGamma​(double alpha, double beta)
      Return a random double drawn from a Gamma distribution with mean alpha*beta and variance alpha*beta^2.
      double nextGamma​(double alpha, double beta, double lambda)
      Return a random double drawn from a Gamma distribution with mean alpha*beta+lamba and variance alpha*beta^2.
      double nextGaussian()
      Return a random double drawn from a Gaussian distribution with mean 0 and variance 1.
      double nextGaussian​(double m, double s2)
      Return a random double drawn from a Gaussian distribution with mean m and variance s2.
      int nextPoisson()
      Return nextPoisson(1).
      int nextPoisson​(double lambda)
      Return random integer from Poission with parameter lambda.
      double nextUniform()
      Return a random double in the range 0 to 1, inclusive, uniformly sampled from that range.
      double nextUniform​(double a, double b)
      Return a random double in the range a to b, inclusive, uniformly sampled from that range.
      double oldNextGamma​(int ia)  

      • Methods inherited from class java.util.Random

        doubles, doubles, doubles, doubles, ints, ints, ints, ints, longs, longs, longs, longs, next, nextBytes, nextDouble, nextFloat, nextInt, nextInt, nextLong, setSeed

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • ONE_OVER_E

        public static final double ONE_OVER_E

    • Constructor Detail

      • Randoms

        public Randoms​(int seed)

      • Randoms

        public Randoms()

    • Method Detail

      • nextPoisson

        public int nextPoisson​(double lambda)
        Return random integer from Poission with parameter lambda. The mean of this distribution is lambda. The variance is lambda.

      • nextPoisson

        public int nextPoisson()
        Return nextPoisson(1).

      • nextBoolean

        public boolean nextBoolean()
        Return a random boolean, equally likely to be true or false.
        Overrides:
        nextBoolean in class java.util.Random

      • nextBoolean

        public boolean nextBoolean​(double p)
        Return a random boolean, with probability p of being true.

      • nextBitSet

        public java.util.BitSet nextBitSet​(int size,
                                   double p)
        Return a random BitSet with "size" bits, each having probability p of being true.

      • nextUniform

        public double nextUniform()
        Return a random double in the range 0 to 1, inclusive, uniformly sampled from that range. The mean of this distribution is 0.5. The variance is 1/12.

      • nextUniform

        public double nextUniform​(double a,
                          double b)
        Return a random double in the range a to b, inclusive, uniformly sampled from that range. The mean of this distribution is (b-a)/2. The variance is (b-a)^2/12

      • nextDiscrete

        public int nextDiscrete​(double[] a)
        Draw a single sample from multinomial "a".

      • nextDiscrete

        public int nextDiscrete​(double[] a,
                        double sum)
        draw a single sample from (unnormalized) multinomial "a", with normalizing factor "sum".

      • nextGaussian

        public double nextGaussian()
        Return a random double drawn from a Gaussian distribution with mean 0 and variance 1.
        Overrides:
        nextGaussian in class java.util.Random

      • nextGaussian

        public double nextGaussian​(double m,
                           double s2)
        Return a random double drawn from a Gaussian distribution with mean m and variance s2.

      • nextGamma

        public double nextGamma()
        Return a random double drawn from a Gamma distribution with mean 1.0 and variance 1.0.

      • nextGamma

        public double nextGamma​(double alpha)
        Return a random double drawn from a Gamma distribution with mean alpha and variance 1.0.

      • oldNextGamma

        public double oldNextGamma​(int ia)

      • nextGamma

        public double nextGamma​(double alpha,
                        double beta)
        Return a random double drawn from a Gamma distribution with mean alpha*beta and variance alpha*beta^2.

      • nextGamma

        public double nextGamma​(double alpha,
                        double beta,
                        double lambda)
        Return a random double drawn from a Gamma distribution with mean alpha*beta+lamba and variance alpha*beta^2. Note that this means the pdf is: frac{ x^{alpha-1} exp(-x/beta) }{ beta^alpha Gamma(alpha) } in other words, beta is a "scale" parameter. An alternative parameterization would use 1/beta, the "rate" parameter.

      • nextExp

        public double nextExp()
        Return a random double drawn from an Exponential distribution with mean 1 and variance 1.

      • nextExp

        public double nextExp​(double beta)
        Return a random double drawn from an Exponential distribution with mean beta and variance beta^2.

      • nextExp

        public double nextExp​(double beta,
                      double lambda)
        Return a random double drawn from an Exponential distribution with mean beta+lambda and variance beta^2.

      • nextChiSq

        public double nextChiSq()
        Return a random double drawn from an Chi-squarted distribution with mean 1 and variance 2. Equivalent to nextChiSq(1)

      • nextChiSq

        public double nextChiSq​(int df)
        Return a random double drawn from an Chi-squared distribution with mean df and variance 2*df.

      • nextChiSq

        public double nextChiSq​(int df,
                        double lambda)
        Return a random double drawn from an Chi-squared distribution with mean df+lambda and variance 2*df.

      • nextBeta

        public double nextBeta​(double alpha,
                       double beta)
        Return a random double drawn from a Beta distribution with mean a/(a+b) and variance ab/((a+b+1)(a+b)^2).

      • asJavaRandom

        @Deprecated
public java.util.Random asJavaRandom()
        Deprecated.
        Wrap this instance as a java random, so it can be passed to legacy methods. All methods of the returned java.util.Random object will affect the state of this object, as well.

      • main

        public static void main​(java.lang.String[] args)