RWTRandBinomial<Generator>


RWTRandBinomial<Generator>RWTRand<Generator>

Data Type and Member Function Indexes
Synopsis
Descripton
Example
Public Constructors
Public Operator
Public Member Functions

Data Type and Member Function Indexes
(exclusive of constructors and destructors)

Member Functions
n() operator()()	p() setN()	setP()

Synopsis

#include <rw/rand.h>
RWTRandBinomial<Generator> gen;

Descripton

Class RWTRandBinomial<Generator> generates random numbers from a binomial distribution:

where n is the number of trials, and p is the probability of success. The algorithm used to generate the random numbers begins with random numbers generated from a uniform distribution on the interval [0, 1]. Thus, the speed and statistical properties of the binomial random number generator may be changed by varying the Generator template parameter responsible for generating the uniformly distributed numbers.

The class Generator must be a function object whose function call operator returns a uniform random double between 0 and 1. The class RWRandGenerator supplied with the library may be used.

Example

#include <rw/rand.h>
#include <iostream.h>
#include "myrand.h"

int main()  {
// Create a uniform generator on [0, 1] with an 
// initial seed value.
  RWRandGenerator uniform(123456L);  

// Create a binomial generator with number of trials 25 and
// probability of success = 0.34 using the above uniform
// generator.
RWTRandBinomial<RWRandGenerator> binomial(uniform, 25, 0.34);

// Create a binomial generator with number of trials = 1 and
// probability of success = .5 using class RWRandGenerator.
  RWTRandBinomial<RWRandGenerator> binomialOne;

// Create a binomial generator with number of trials = 31 
// and probability of success = .27 using a class 
// MyDoubleRand to generate the uniform [0, 1] deviates.
  RWTRandBinomial<MyDoubleRand> myBinomial(31, .27);

// Print a few values
  for ( int j = 0; j < 10; t+j )
  {
    cout << "binomial n=25, p=.34 = " << binomial();
    cout << "\nbinomial n=1, p=0.5 = " << binomialOne();
    cout << "\nbinomial n=31 and p=.27 = " 
         << myBinomial() << endl;
}
  
// Restart one of the generators with another seed value
// using the RWRandGenerator method restart()
  ( binomialOne.generator() ).restart( 654321L);

  return 0;
}

Public Constructors

RWTRandBinomial(unsigned n = 1, double p = 0.5);

Constructs a generator with the number of trials = n and the probability of success = p.

RWTRandBinomial(const Generator& g, unsigned n=1, 
                double p=.5);

Constructs a generator with underlying uniform [0, 1] generator g, number of trials = n, and probability of success = p.

RWTRandBinomial(const RWTRandBinomial<Generator>& g);

Constructs self as a copy of g.

Public Operator

double    operator()()

Returns the next random number in the sequence.

Public Member Functions

double
n() const;

Returns the number of trials for the distribution.

double
p() const;

Returns the probability of success for the distribution.

void
setN(unsigned n);

Sets the number of trials for the distribution to n.

void
setP(double p);

Sets the probability of success for the distribution to p.