std::lognormal_distribution(3)

NAME
std::lognormal_distribution - std::lognormal_distribution

Synopsis
   Defined in header <random>
   template< class RealType = double > (since C++11)
   class lognormal_distribution;
   The lognormal_distribution random number distribution produces random numbers x > 0
   according to a Log-normal distribution:
   \({\small f(x;m,s) = \frac{1}{sx\sqrt{2\pi} } \exp{(-\frac{ {(\ln{x} - m)}^{2}
   }{2{s}^{2} })} }\)f(x; m,s) =
   1
   sx
   √
   2 π
   exp⎛
   ⎜
   ⎝-
   (ln x - m)2
   2s2
   ⎞
   ⎟
   ⎠
   The parameters m and s are, respectively, the mean and standard deviation of the
   natural logarithm of x.
   std::lognormal_distribution satisfies all requirements of 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
   constructor constructs new distribution
   (C++11) (public member function)
   reset resets the internal state of the distribution
   (C++11) (public member function)

Generation
   operator() generates the next random number in the distribution
   (C++11) (public member function)

Characteristics
   m returns the distribution parameters
   s (public member function)
   (C++11)
   param gets or sets the distribution parameter object
   (C++11) (public member function)
   min returns the minimum potentially generated value
   (C++11) (public member function)
   max returns the maximum potentially generated value
   (C++11) (public member function)

Non-member functions
   operator==
   operator!= compares two distribution objects
   (C++11) (function)
   (C++11)(removed in C++20)
   operator<< performs stream input and output on pseudo-random number
   operator>> distribution
   (C++11) (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::lognormal_distribution<> d(1.6, 0.25);
     std::map<int, int> hist;
     for (int n = 0; n < 1e4; ++n)
         ++hist[std::round(d(gen))];
     for (std::cout << std::fixed << std::setprecision(1); auto [x, y] : hist)
         std::cout << std::hex << x << ' ' << std::string(y / 200, '*') << '\n';
 }

Possible output:
 2
 3 ***
 4 *************
 5 ***************
 6 *********
 7 ****
 8 *
 9
 a
 b
 c

External links
   Weisstein, Eric W. "Log Normal Distribution." From MathWorld — A Wolfram Web
   Resource.