std:: weibull_distribution
From cppreference.com
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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 .
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
|
(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) |
Non-member functions
|
(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) |
Example
Run this code
#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
| 1. | Weisstein, Eric W. "Weibull Distribution." From MathWorld — A Wolfram Web Resource. |
| 2. | Weibull distribution — From Wikipedia. |