1 //===----------------------------------------------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // REQUIRES: long_tests
14 // template<class RealType = double>
15 // class gamma_distribution
17 // template<class _URNG> result_type operator()(_URNG& g);
35 typedef std::gamma_distribution<> D;
36 typedef D::param_type P;
37 typedef std::mt19937 G;
40 const int N = 1000000;
41 std::vector<D::result_type> u;
42 for (int i = 0; i < N; ++i)
44 D::result_type v = d(g);
48 double mean = std::accumulate(u.begin(), u.end(), 0.0) / u.size();
52 for (unsigned i = 0; i < u.size(); ++i)
54 double dbl = (u[i] - mean);
61 double dev = std::sqrt(var);
62 skew /= u.size() * dev * var;
63 kurtosis /= u.size() * var * var;
65 double x_mean = d.alpha() * d.beta();
66 double x_var = d.alpha() * sqr(d.beta());
67 double x_skew = 2 / std::sqrt(d.alpha());
68 double x_kurtosis = 6 / d.alpha();
69 assert(std::abs((mean - x_mean) / x_mean) < 0.01);
70 assert(std::abs((var - x_var) / x_var) < 0.01);
71 assert(std::abs((skew - x_skew) / x_skew) < 0.01);
72 assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
75 typedef std::gamma_distribution<> D;
76 typedef D::param_type P;
77 typedef std::mt19937 G;
80 const int N = 1000000;
81 std::vector<D::result_type> u;
82 for (int i = 0; i < N; ++i)
84 D::result_type v = d(g);
88 double mean = std::accumulate(u.begin(), u.end(), 0.0) / u.size();
92 for (unsigned i = 0; i < u.size(); ++i)
94 double dbl = (u[i] - mean);
101 double dev = std::sqrt(var);
102 skew /= u.size() * dev * var;
103 kurtosis /= u.size() * var * var;
105 double x_mean = d.alpha() * d.beta();
106 double x_var = d.alpha() * sqr(d.beta());
107 double x_skew = 2 / std::sqrt(d.alpha());
108 double x_kurtosis = 6 / d.alpha();
109 assert(std::abs((mean - x_mean) / x_mean) < 0.01);
110 assert(std::abs((var - x_var) / x_var) < 0.01);
111 assert(std::abs((skew - x_skew) / x_skew) < 0.01);
112 assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);
115 typedef std::gamma_distribution<> D;
116 typedef D::param_type P;
117 typedef std::mt19937 G;
120 const int N = 1000000;
121 std::vector<D::result_type> u;
122 for (int i = 0; i < N; ++i)
124 D::result_type v = d(g);
128 double mean = std::accumulate(u.begin(), u.end(), 0.0) / u.size();
132 for (unsigned i = 0; i < u.size(); ++i)
134 double dbl = (u[i] - mean);
135 double d2 = sqr(dbl);
141 double dev = std::sqrt(var);
142 skew /= u.size() * dev * var;
143 kurtosis /= u.size() * var * var;
145 double x_mean = d.alpha() * d.beta();
146 double x_var = d.alpha() * sqr(d.beta());
147 double x_skew = 2 / std::sqrt(d.alpha());
148 double x_kurtosis = 6 / d.alpha();
149 assert(std::abs((mean - x_mean) / x_mean) < 0.01);
150 assert(std::abs((var - x_var) / x_var) < 0.01);
151 assert(std::abs((skew - x_skew) / x_skew) < 0.01);
152 assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.01);