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Showing content from https://cplusplus.com/reference/random/fisher_f_distribution/ below:

class template

std::fisher_f_distribution

template <class RealType = double> class fisher_f_distribution;

Fisher F-distribution

Random number distribution that produces floating-point values according to a Fisher F-distribution, which is described by the following probability density function:

This distribution produces random numbers as the result of dividing two independent Chi-squared distributions of m and n degrees of freedom.

The distribution parameters, m and n, are set on construction.

To produce a random value following this distribution, call its member function operator().

Template parameters

RealType: A floating-point type. Aliased as member type result_type.
By default, this is double.

Member types The following aliases are member types of normal_distribution:

member type definition notes result_type The first template parameter (RealType) The type of the numbers generated (defaults to double) param_type not specified The type returned by member param.

Member functions

(constructor): Construct Fisher F-distribution (public member function)

operator(): Generate random number (public member function)

reset: Reset distribution (public member function)

param: Distribution parameters (public member function)

min: Minimum value (public member function)

max: Maximum value (public member function)

Distribution parameters:

m: Degrees of freedom (numerator) (public member function)

n: Degrees of freedom (denominator) (public member function)

Non-member functions

operator<<: Insert into output stream (function template)

operator>>: Extract from input stream (function template)

relational operators: Relational operators (function template)

Example

// fisher_f_distribution
#include <iostream>
#include <random>

int main()
{
  const int nrolls=10000;  // number of experiments
  const int nstars=100;    // maximum number of stars to distribute

  std::default_random_engine generator;
  std::fisher_f_distribution<double> distribution(2.0,2.0);

  int p[10]={};

  for (int i=0; i<nrolls; ++i) {
    double number = distribution(generator);
    if ((number>=0.0)&&(number<10.0)) ++p[int(number)];
  }

  std::cout << "fisher_f_distribution (2.0,2.0):" << std::endl;

  for (int i=0; i<10; ++i) {
    std::cout << i << "-" << (i+1) << ": ";
    std::cout << std::string(p[i]*nstars/nrolls,'*') << std::endl;
  }

  return 0;
}

Possible output:

fisher_f_distribution (2.0,2.0):
0-1: *************************************************
1-2: ****************
2-3: ********
3-4: *****
4-5: ***
5-6: **
6-7: *
7-8: *
8-9: *
9-10: *