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std::weibull_distribution

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< cpp‎ | numeric‎ | random
Revision as of 05:17, 5 June 2013 by P12 (Talk | contribs)

 
 
 
 
 
Defined in header <random>
template< class RealType = double >
class weibull_distribution;
(since C++11)

The weibull_distribution meets the requirements of a RandomNumberDistribution and produces random numbers according to the Weibull distribution:

f(x;a,b) =
a
b


x
b


a-1
exp

-

x
b


a


a is the shape parameter and b the scale parameter.

Contents

Member types

Member type Definition
result_type RealType
param_type the type of the parameter set, unspecified

Member functions

constructs new distribution
(public member function) [edit]
resets the internal state of the distribution
(public member function) [edit]
Generation
generates the next random number in the distribution
(public member function) [edit]
Characteristics
returns the distribution parameters
(public member function) [edit]
gets or sets the distribution parameter object
(public member function) [edit]
returns the minimum potentially generated value
(public member function) [edit]
returns the maximum potentially generated value
(public member function) [edit]

Non-member functions

compares two distribution objects
(function) [edit]
performs stream input and output on pseudo-random number distribution
(function) [edit]

Example

#include <iostream>
#include <iomanip>
#include <string>
#include <map>
#include <random>
#include <cmath>
int main()
{
    std::random_device rd;
    std::mt19937 gen(rd());
 
    std::weibull_distribution<> d;
 
    std::map<int, int> hist;
    for(int n=0; n<10000; ++n) {
        ++hist[std::round(d(gen))];
    }
    for(auto p : hist) {
        std::cout << std::fixed << std::setprecision(1) << std::setw(2)
                  << p.first << ' ' << std::string(p.second/200, '*') << '\n';
    }
}

Output:

0 *******************
 1 *******************
 2 ******
 3 **
 4 
 5 
 6 
 7 
 8

External links