From cppreference.com
template<classRealType=double>classpiecewise_linear_distribution;(since C++11)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 [bi, bi+1). The distribution is such that the probability density at each interval boundary is exactly the predefined value pi.
The probability density for any bi≤x<bi+1 is
pibi+1-xbi+1-bi + pi+1x-bibi+1-bi
, where probability densities at interval boundaries pk are calculated as wk/S where S is the sum of all
12(wk+wk+1)(bk+1−bk)
.
The set of interval boundaries bi and the set of weights at boundaries wi are the parameters of this distribution.
std::piecewise_linear_distribution
satisfies all requirements of
.
Template parameters
RealType - The result type generated by the generator. The effect is undefined if this is not one of float, double, or longdouble. Member types
Member type Definition result_type(C++11)RealTypeparam_typethe type of the parameter set, see
. Member functions
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
(C++11)
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)
Non-member functions
Example
Run this code
#include<iomanip>#include<iostream>#include<map>#include<random>#include<string>intmain(){std::random_devicerd;std::mt19937gen{rd()};// increase the probability from 0 to 5// remain flat from 5 to 10// decrease from 10 to 15 at the same ratestd::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(intn{};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';}Possible output:
00 * 01 *** 02 **** 03 ****** 04 ********* 05 ********* 06 ********* 07 ********** 08 ********* 09 ********** 10 ********* 11 ******* 12 **** 13 *** 14 *