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.
| w k |
| S (b i+1 - b i) |
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 | RealType |
param_type | the type of the parameter set, see RandomNumberDistribution. |
| constructs new distribution (public member function) |
|
| resets the internal state of the distribution (public member function) |
|
Generation |
|
| generates the next random number in the distribution (public member function) |
|
Characteristics |
|
| returns the distribution parameters (public member function) |
|
| gets or sets the distribution parameter object (public member function) |
|
| returns the minimum potentially generated value (public member function) |
|
| returns the maximum potentially generated value (public member function) |
|
| compares two distribution objects (function) |
|
| performs stream input and output on pseudo-random number distribution (function template) |
#include <iostream>
#include <string>
#include <map>
#include <random>
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=0; n<10000; ++n) {
++hist[d(gen)];
}
for(auto p : hist) {
std::cout << p.first << ' ' << std::string(p.second/100, '*') << '\n';
}
}Output:
0 ************************************************** 10 ********** 11 ********* 12 ********* 13 ********** 14 *********
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