1 files changed, 103 insertions, 0 deletions
diff --git a/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eval.pass.cpp b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eval.pass.cpp
new file mode 100644
index 00000000000..f071e850747
--- /dev/null
+++ b/libcxx/test/std/numerics/rand/rand.dis/rand.dist.bern/rand.dist.bern.bernoulli/eval.pass.cpp
@@ -0,0 +1,103 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <random>
+
+// class bernoulli_distribution
+
+// template<class _URNG> result_type operator()(_URNG& g);
+
+#include <random>
+#include <numeric>
+#include <vector>
+#include <cassert>
+
+template <class T>
+inline
+T
+sqr(T x)
+{
+    return x * x;
+}
+
+int main()
+{
+    {
+        typedef std::bernoulli_distribution D;
+        typedef std::minstd_rand G;
+        G g;
+        D d(.75);
+        const int N = 100000;
+        std::vector<D::result_type> u;
+        for (int i = 0; i < N; ++i)
+            u.push_back(d(g));
+        double mean = std::accumulate(u.begin(), u.end(),
+                                              double(0)) / u.size();
+        double var = 0;
+        double skew = 0;
+        double kurtosis = 0;
+        for (int i = 0; i < u.size(); ++i)
+        {
+            double d = (u[i] - mean);
+            double d2 = sqr(d);
+            var += d2;
+            skew += d * d2;
+            kurtosis += d2 * d2;
+        }
+        var /= u.size();
+        double dev = std::sqrt(var);
+        skew /= u.size() * dev * var;
+        kurtosis /= u.size() * var * var;
+        kurtosis -= 3;
+        double x_mean = d.p();
+        double x_var = d.p()*(1-d.p());
+        double x_skew = (1 - 2 * d.p())/std::sqrt(x_var);
+        double x_kurtosis = (6 * sqr(d.p()) - 6 * d.p() + 1)/x_var;
+        assert(std::abs((mean - x_mean) / x_mean) < 0.01);
+        assert(std::abs((var - x_var) / x_var) < 0.01);
+        assert(std::abs((skew - x_skew) / x_skew) < 0.01);
+        assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.02);
+    }
+    {
+        typedef std::bernoulli_distribution D;
+        typedef std::minstd_rand G;
+        G g;
+        D d(.25);
+        const int N = 100000;
+        std::vector<D::result_type> u;
+        for (int i = 0; i < N; ++i)
+            u.push_back(d(g));
+        double mean = std::accumulate(u.begin(), u.end(),
+                                              double(0)) / u.size();
+        double var = 0;
+        double skew = 0;
+        double kurtosis = 0;
+        for (int i = 0; i < u.size(); ++i)
+        {
+            double d = (u[i] - mean);
+            double d2 = sqr(d);
+            var += d2;
+            skew += d * d2;
+            kurtosis += d2 * d2;
+        }
+        var /= u.size();
+        double dev = std::sqrt(var);
+        skew /= u.size() * dev * var;
+        kurtosis /= u.size() * var * var;
+        kurtosis -= 3;
+        double x_mean = d.p();
+        double x_var = d.p()*(1-d.p());
+        double x_skew = (1 - 2 * d.p())/std::sqrt(x_var);
+        double x_kurtosis = (6 * sqr(d.p()) - 6 * d.p() + 1)/x_var;
+        assert(std::abs((mean - x_mean) / x_mean) < 0.01);
+        assert(std::abs((var - x_var) / x_var) < 0.01);
+        assert(std::abs((skew - x_skew) / x_skew) < 0.01);
+        assert(std::abs((kurtosis - x_kurtosis) / x_kurtosis) < 0.02);
+    }
+}