1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // REQUIRES: long_tests
11 
12 // <random>
13 
14 // template<class IntType = int>
15 // class discrete_distribution
16 
17 // template<class _URNG> result_type operator()(_URNG& g, const param_type& parm);
18 
19 #include <random>
20 #include <vector>
21 #include <cassert>
22 
main()23 int main()
24 {
25     {
26         typedef std::discrete_distribution<> D;
27         typedef D::param_type P;
28         typedef std::minstd_rand G;
29         G g;
30         D d;
31         double p0[] = {.3, .1, .6};
32         P p(p0, p0+3);
33         const int N = 10000000;
34         std::vector<D::result_type> u(3);
35         for (int i = 0; i < N; ++i)
36         {
37             D::result_type v = d(g, p);
38             assert(0 <= v && v <= 2);
39             u[v]++;
40         }
41         std::vector<double> prob = p.probabilities();
42         for (int i = 0; i <= 2; ++i)
43             assert(std::abs((double)u[i]/N - prob[i]) / prob[i] < 0.001);
44     }
45 }
46