std::piecewise_constant_distribution

template <class RealType = double> class piecewise_constant_distribution;

Piecewise constant distribution

Random number distribution that produces floating-point values that are uniformly distributed over each of a sequence of contiguous subintervals, as defined by the following probability density function:

A set of n non-negative individual weights (the w's) for each of the subintervals [b_i,b_i+1) are set on construction. The probability of producing a value within each subinterval being their corresponding weight (w_i) divided by the total of all weights.

To produce a random value following this distribution, call its member function operator().

Template parameters

RealType: A floating-point type. Aliased as member type result_type.
By default, this is double.

Member types

The following aliases are member types of piecewise_constant_distribution:

member type	definition	notes
`result_type`	The first template parameter (`RealType`)	The type of the numbers generated (defaults to `double`)
`param_type`	not specified	The type returned by member param.

Member functions

(constructor): Construct piecewise constant distribution (public member function)

operator(): Generate random number (public member function)

reset: Reset distribution (public member function)

param: Distribution parameters (public member function)

min: Minimum value (public member function)

max: Maximum value (public member function)

Distribution parameters:

intervals: Intervals (public member function)

densities: Densities (public member function)

Non-member functions

operator<<: Insert into output stream (function template)

operator>>: Extract from input stream (function template)

relational operators: Relational operators (function template)

Example

// piecewise_constant_distribution #include <iostream> #include <array> #include <random> int main() { const int nrolls = 10000; // number of experiments const int nstars = 100; // maximum number of stars to distribute std::default_random_engine generator; std::array<double,6> intervals {0.0, 2.0, 4.0, 6.0, 8.0, 10.0}; std::array<double,5> weights {2.0, 1.0, 2.0, 1.0, 2.0}; std::piecewise_constant_distribution<double> distribution (intervals.begin(),intervals.end(),weights.begin()); int p[10]={}; for (int i=0; i<nrolls; ++i) { int number = distribution(generator); ++p[number]; } std::cout << "a piecewise_constant_distribution:" << std::endl; for (int i=0; i<10; ++i) { std::cout << i << "-" << i+1 << ": "; std::cout << std::string(p[i]*nstars/nrolls,'*') << std::endl; } return 0; }

Possible output:

a piecewise_constant_distribution: 0-1: ************ 1-2: ************* 2-3: ***** 3-4: ****** 4-5: ************ 5-6: ************ 6-7: ****** 7-8: ****** 8-9: ************ 9-10: ************

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non-member functions