std::weibull_distribution
From cppreference.com
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
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
|
RealType |
param_type
|
the type of the parameter set, see RandomNumberDistribution .
|
[edit] Member functions
constructs new distribution (public member function) |
|
resets the internal state of the distribution (public member function) |
|
Generation |
|
generates the next random number in the distribution (public member function) |
|
Characteristics |
|
returns the distribution parameters (public member function) |
|
gets or sets the distribution parameter object (public member function) |
|
returns the minimum potentially generated value (public member function) |
|
returns the maximum potentially generated value (public member function) |
[edit] Non-member functions
compares two distribution objects (function) |
|
performs stream input and output on pseudo-random number distribution (function template) |
[edit] Example
Run this code
#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
[edit] External links
- Weisstein, Eric W. "Weibull Distribution." From MathWorld--A Wolfram Web Resource.
- Weibull distribution. From Wikipedia.