Defined in header <random> | ||
|---|---|---|
template< class RealType = double > class piecewise_constant_distribution; | (since C++11) |
std::piecewise_constant_distribution produces random floating-point numbers, which are uniformly distributed within each of the several subintervals [b
i, b
i+1), each with its own weight w
i. The set of interval boundaries and the set of weights are the parameters of this distribution. The probability density for any b.
std::piecewise_constant_distribution satisfies all requirements of RandomNumberDistribution.
| RealType | - | The result type generated by the generator. The effect is undefined if this is not one of float, double, or long double. |
| Member type | Definition |
|---|---|
result_type (C++11) | RealType |
param_type (C++11) | the type of the parameter set, see RandomNumberDistribution. |
|
(C++11) | constructs new distribution (public member function) |
|
(C++11) | resets the internal state of the distribution (public member function) |
Generation |
|
|
(C++11) | generates the next random number in the distribution (public member function) |
Characteristics |
|
| returns the distribution parameters (public member function) |
|
|
(C++11) | gets or sets the distribution parameter object (public member function) |
|
(C++11) | returns the minimum potentially generated value (public member function) |
|
(C++11) | returns the maximum potentially generated value (public member function) |
|
(C++11)(C++11)(removed in C++20) | compares two distribution objects (function) |
|
(C++11) | performs stream input and output on pseudo-random number distribution (function template) |
#include <iostream>
#include <map>
#include <random>
#include <string>
int main()
{
std::random_device rd;
std::mt19937 gen(rd());
// 50% of the time, generate a random number between 0 and 1
// 50% of the time, generate a random number between 10 and 15
std::vector<double> i {0, 1, 10, 15};
std::vector<double> w {1, 0, 1};
std::piecewise_constant_distribution<> d(i.begin(), i.end(), w.begin());
std::map<int, int> hist;
for (int n {}; n < 1e4; ++n)
++hist[d(gen)];
for (std::cout << std::hex << std::uppercase; auto [x, y] : hist)
std::cout << x << ' ' << std::string(y / 100, '*') << '\n';
}Possible output:
0 ************************************************** A ********** B ********* C ********* D ********** E *********
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