normal_distribution::operator()
Returns a random value.
template<class Engine>
result_type operator()(Engine& eng);
template<class Engine>
result_type operator()(Engine& eng,
const param_type& par0);
Parameters
Engine
The type of the random engine.eng
The random engine.par0
The parameter package used as a source for the random value.
Remarks
The first member function uses the engine eng as a source of uniformly distributed random values and returns values with a probability density of pr(x) = 1 / (√(2 * pi) * stored_sigma) * (e)^(-(x - stored_mean)2 / (2 * stored_sigma^2)).
The second member function behaves the same, except that it uses the parameters stored in par0.
Example
// std_tr1__random__normal_distribution_operator_fn.cpp
// compile with: /EHsc
#include <random>
#include <iostream>
typedef std::ranlux64_base_01 Myeng;
typedef std::normal_distribution<double> Mydist;
int main()
{
Myeng eng;
Mydist dist(1.5, 2.0);
Mydist::input_type engval = eng();
Mydist::result_type distval = dist(eng);
distval = distval; // to quiet "unused" warnings
engval = engval;
std::cout << "mean == " << dist.mean() << std::endl;
std::cout << "sigma == " << dist.sigma() << std::endl;
dist.reset(); // discard any cached values
std::cout << "a random value == " << dist(eng) << std::endl;
std::cout << "a random value == " << dist(eng) << std::endl;
std::cout << "a random value == " << dist(eng) << std::endl;
return (0);
}
mean == 1.5 sigma == 2 a random value == 0.0275648 a random value == 0.0738393 a random value == 4.47125
Requirements
Header: <random>
Namespace: std