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: \(\small{f(x;a,b)=\frac{a}{b}{(\frac{x}{b})}^{a-1}\exp{(-{(\frac{x}{b})}^{a})} }\)f(x;a,b) =
a is the shape parameter and b the scale parameter.
std::weibull_distribution satisfies RandomNumberDistribution.
| RealType | - | The result type generated by the generator. The effect is undefined if this is not one of float, double, or long double. |
| Member type | Definition |
|---|---|
result_type (C++11) | RealType |
param_type (C++11) | the type of the parameter set, see RandomNumberDistribution. |
|
(C++11) | constructs new distribution (public member function) |
|
(C++11) | resets the internal state of the distribution (public member function) |
Generation |
|
|
(C++11) | generates the next random number in the distribution (public member function) |
Characteristics |
|
|
(C++11) | returns the distribution parameters (public member function) |
|
(C++11) | gets or sets the distribution parameter object (public member function) |
|
(C++11) | returns the minimum potentially generated value (public member function) |
|
(C++11) | returns the maximum potentially generated value (public member function) |
|
(C++11)(C++11)(removed in C++20) | compares two distribution objects (function) |
|
(C++11) | performs stream input and output on pseudo-random number distribution (function template) |
#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
| 1. | Weisstein, Eric W. "Weibull Distribution." From MathWorld — A Wolfram Web Resource. |
| 2. | Weibull distribution — From Wikipedia. |
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