public member function
<random>
| (1) | explicit lognormal_distribution ( result_type m = 0.0, result_type s = 1.0 );
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| (2) | explicit lognormal_distribution ( const param_type& parm ); |
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Construct lognormal distribution
Constructs a lognormal_distribution object, adopting the distribution parameters specified either by m and s or by object parm.
Parameters
- m
- Mean of the underlying normal distribution formed by the logarithm transformations of the possible values in this distribution.
result_type is a member type that represents the type of the random numbers generated on each call to operator(). It is defined as an alias of the first class template parameter (RealType).
- s
- Standard deviation of the underlying normal distribution formed by the logarithm transformations of the possible values in this distribution.
This shall be a positive value (s>0).
result_type is a member type that represents the type of the random numbers generated on each call to operator(). It is defined as an alias of the first class template parameter (RealType).
- parm
- An object representing the distribution's parameters, obtained by a call to member function param.
param_type is a member type.
Example
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// lognormal_distribution example
#include <iostream>
#include <chrono>
#include <random>
int main()
{
// construct a trivial random generator engine from a time-based seed:
unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();
std::default_random_engine generator (seed);
std::lognormal_distribution<double> distribution (0.0,1.0);
std::cout << "some lognormal-distributed(0.0,1.0) results:" << std::endl;
for (int i=0; i<10; ++i)
std::cout << distribution(generator) << std::endl;
return 0;
}
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Possible output:
some lognormal-distributed(0.0,1.0) results:
1.76931
0.426828
2.13448
3.41825
0.574683
1.7239
1.49771
1.27637
0.371665
1.13434
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