std::piecewise_linear_distribution

Since C++11

Header: <random>

std::piecewise_linear_distribution produces random floating-point numbers, which are distributed according to a linear probability density function within each of the several subintervals (\small{[b_i, b_{i+1})})[bi, bi+1). The distribution is such that the probability density at each interval boundary is exactly the predefined value (\small{p_i})pi.

# Declarations

template< class RealType = double >
class piecewise_linear_distribution;

(since C++11)

# Example

#include <iomanip>
#include <iostream>
#include <map>
#include <random>
#include <string>
 
int main()
{
    std::random_device rd;
    std::mt19937 gen{rd()};
    // increase the probability from 0 to 5
    // remain flat from 5 to 10
    // decrease from 10 to 15 at the same rate
    std::vector<double> i{0, 5, 10, 15};
    std::vector<double> w{0, 1, 1, 0};
    std::piecewise_linear_distribution<> d{i.begin(), i.end(), w.begin()};
 
    std::map<int, int> hist;
    for (int n{}; n < 1e4; ++n)
        ++hist[d(gen)];
 
    for (auto [x, y] : hist)
        std::cout << std::setw(2) << std::setfill('0') << x
                  << ' ' << std::string(y / 100, '*') << '\n';
}