std::weibull_distribution
From cppreference.com
C++
Feature test macros (C++20)
Concepts library (C++20)
Metaprogramming library (C++11)
Ranges library (C++20)
Filesystem library (C++17)
Concurrency support library (C++11)
Execution control library (C++26)
Numerics library
Mathematical special functions (C++17)
Mathematical constants (C++20)
Basic linear algebra algorithms (C++26)
Data-parallel types (SIMD) (C++26)
Floating-point environment (C++11)
Bit manipulation (C++20)
Saturation arithmetic (C++26)
(C++17)
(C++17)
(C++17)
(C++17)
(C++17)
(C++17)
Pseudo-random number generation
(C++20)
(C++11)
(C++11)
(C++11)
(C++26)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++26)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
weibull_distribution
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
std::weibull_distribution
Member functions
Generation
Characteristics
Non-member functions
(C++11)(C++11)(until C++20)
(C++11)(C++11)
Defined in header
<random>
template< class RealType = double >
class weibull_distribution;
(since C++11)
class weibull_distribution;
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) = ab⎛
⎜
⎝xb⎞
⎟
⎠a-1
exp⎛
⎜
⎝-⎛
⎜
⎝xb⎞
⎟
⎠a
⎞
⎟
⎠
a is the shape parameter and b the scale parameter.
std::weibull_distribution satisfies RandomNumberDistribution.
Contents
[edit] 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.
[edit] Member types
Member type
Definition
result_type (C++11)
RealType
[edit] Member functions
Generation
Characteristics
[edit] Non-member functions
(C++11)
(function template) [edit]
[edit] 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
[edit] External links
1.
Weisstein, Eric W. "Weibull Distribution." From MathWorld — A Wolfram Web Resource.
2.
Weibull distribution — From Wikipedia.