1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // REQUIRES: long_tests
10 
11 // <random>
12 
13 // template<class IntType = int>
14 // class discrete_distribution
15 
16 // template<class _URNG> result_type operator()(_URNG& g, const param_type& parm);
17 
18 #include <cassert>
19 #include <cstdlib>
20 #include <random>
21 #include <vector>
22 
main(int,char **)23 int main(int, char**)
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   return 0;
47 }
48