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std::weibull_distribution - cppreference.com

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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:

{{mathjax-or|1=\(\small{f(x;a,b)=\frac{a}{b}{(\frac{x}{b})}^{a-1}\exp{(-{(\frac{x}{b})}^{a})} }\)|2=f(x;a,b) = ⎛
⎜
⎝⎞
⎟
⎠a-1
 exp⎛
⎜
⎝-⎛
⎜
⎝⎞
⎟
⎠a
⎞
⎟
⎠}}

a is the shape parameter and b the scale parameter.

std::weibull_distribution satisfies RandomNumberDistribution.

Template parameters

RealType - The result type generated by the generator. The effect is undefined if this is not one of float, double, or long double.

Member types

Member type Definition
result_type (C++11) RealType
param_type (C++11) the type of the parameter set, see RandomNumberDistribution.

Member functions

constructs new distribution
(public member function) [edit]

(C++11)

 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

(C++11)

 returns the distribution parameters
(public member function) [edit]

(C++11)

 gets or sets the distribution parameter object
(public member function) [edit]

(C++11)

 returns the minimum potentially generated value
(public member function) [edit]

(C++11)

 returns the maximum potentially generated value
(public member function) [edit]

Non-member functions

Example

#include <cmath>
#include <iomanip>
#include <iostream>
#include <map>
#include <random>
#include <string>

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))];

    std::cout << std::fixed << std::setprecision(1) << std::hex;
    for (auto [x, y] : hist)
        std::cout << x << ' ' << std::string(y / 200, '*') << '\n';
}

Possible output: 

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

External links