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std::weibull_distribution

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< cpp‎ | numeric‎ | random
Revision as of 15:21, 2 November 2012 by P12bot (Talk | contribs)

 
 
 
 
 
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.

Contents

Member types

Member type Definition
result_type RealType
param_type the type of the parameter set, unspecified

Member functions

Template:cpp/numeric/random/distribution/dcl list constructorTemplate:cpp/numeric/random/distribution/dcl list resetTemplate:cpp/numeric/random/distribution/dcl list operator()Template:cpp/numeric/random/weibull distribution/dcl list aTemplate:cpp/numeric/random/weibull distribution/dcl list bTemplate:cpp/numeric/random/distribution/dcl list paramTemplate:cpp/numeric/random/distribution/dcl list minTemplate:cpp/numeric/random/distribution/dcl list max
Generation
Characteristics

Non-member functions

Template:cpp/numeric/random/distribution/dcl list operator cmpTemplate:cpp/numeric/random/distribution/dcl list operator ltltgtgt

Example

#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

External links