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std::piecewise_constant_distribution

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Pseudo-random number generation
Engines and engine adaptors
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Distributions
Uniform distributions
Bernoulli distributions
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piecewise_constant_distribution
(C++11)
Seed Sequences
(C++11)
C library
 
 
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
i
≤x<b
i+1
is
w
k
S (b
i+1
- b
i
)
. where S is the sum of all weights.

Contents

Member types

Member type Definition
result_type RealType
param_type the type of the parameter set, unspecified

Member functions

Template:cpp/numeric/random/distribution/dcl list constructorTemplate:cpp/numeric/random/distribution/dcl list resetTemplate:cpp/numeric/random/distribution/dcl list operator()Template:cpp/numeric/random/piecewise constant distribution/dcl list intervalsTemplate:cpp/numeric/random/piecewise constant distribution/dcl list densitiesTemplate:cpp/numeric/random/distribution/dcl list paramTemplate:cpp/numeric/random/distribution/dcl list minTemplate:cpp/numeric/random/distribution/dcl list max
Generation
Characteristics

Non-member functions

Template:cpp/numeric/random/distribution/dcl list operator cmpTemplate:cpp/numeric/random/distribution/dcl list operator ltltgtgt

Example

#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 *********