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std::normal_distribution

From cppreference.com
 
 
 
Pseudo-random number generation
Engines and engine adaptors
linear_congruential_engine(C++11)
mersenne_twister_engine(C++11)
subtract_with_carry_engine(C++11)
discard_block_engine(C++11)
independent_bits_engine(C++11)
shuffle_order_engine(C++11)
Generators
random_device(C++11)
Distributions
Uniform distributions
uniform_int_distribution(C++11)
uniform_real_distribution(C++11)
generate_canonical(C++11)
Bernoulli distributions
bernoulli_distribution(C++11)
binomial_distribution(C++11)
negative_binomial_distribution(C++11)
geometric_distribution(C++11)
Poisson distributions
poisson_distribution(C++11)
exponential_distribution(C++11)
gamma_distribution(C++11)
weibull_distribution(C++11)
extreme_value_distribution(C++11)
Normal distributions
normal_distribution(C++11)
lognormal_distribution(C++11)
chi_squared_distribution(C++11)
cauchy_distribution(C++11)
fisher_f_distribution(C++11)
student_t_distribution(C++11)
Sampling distributions
discrete_distribution(C++11)
piecewise_constant_distribution(C++11)
piecewise_linear_distribution(C++11)
Seed Sequences
seed_seq(C++11)
C library
rand
srand
RAND_MAX
 
 
Defined in header <random>
template< class RealType = double >
class normal_distribution;
(since C++11)

Contents

[edit] Member types

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

[edit] Member functions

constructs new distribution
(public member function) [edit]
resets the internal state of the distribution
(public member function) [edit]
Generation
generates the next random number in the distribution
(public member function) [edit]
Characteristics
gets or sets the distribution parameter object
(public member function) [edit]
returns the minimum potentially generated value
(public member function) [edit]
returns the maximum potentially generated value
(public member function) [edit]

[edit] Non-member functions

compares two distribution objects
(function) [edit]
performs stream input and output on pseudo-random number distribution
(function) [edit]

[edit] Example

#include <iostream>
#include <iomanip>
#include <string>
#include <map>
#include <random>
#include <cmath>
int main()
{
    std::random_device rd;
    std::mt19937 gen(rd());
 
    // values near the mean are the most likely
    // standard deviation affects the dispersion of generated values from the mean
    std::normal_distribution<> d(5,2);
 
    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:

-2 
-1 
 0 
 1 *
 2 ***
 3 ******
 4 ********
 5 **********
 6 ********
 7 *****
 8 ***
 9 *
10 
11 
12

[edit] External links

Weisstein, Eric W. "Normal Distribution." From MathWorld--A Wolfram Web Resource.