1 files changed, 50 insertions, 0 deletions
diff --git a/src/boost/libs/histogram/benchmark/generator.hpp b/src/boost/libs/histogram/benchmark/generator.hpp
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+++ b/src/boost/libs/histogram/benchmark/generator.hpp
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+// Copyright 2019 Hans Dembinski
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt
+// or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include <array>
+#include <random>
+
+using uniform = std::uniform_real_distribution<>;
+using uniform_int = std::uniform_int_distribution<>;
+using normal = std::normal_distribution<>;
+
+template <class Distribution, class... Ts>
+Distribution init(Ts...);
+
+template <>
+uniform init<uniform>() {
+  return uniform{0.0, 1.0};
+}
+
+template <>
+normal init<normal>() {
+  return normal{0.5, 0.3};
+}
+
+template <>
+uniform_int init<uniform_int, int>(int n) {
+  return uniform_int{0, n};
+}
+
+template <class Distribution, std::size_t N = 1 << 15>
+struct generator : std::array<double, N> {
+  using base_t = std::array<double, N>;
+
+  template <class... Ts>
+  generator(Ts... ts) {
+    std::default_random_engine rng(1);
+    auto dis = init<Distribution>(ts...);
+    std::generate(base_t::begin(), base_t::end(), [&] { return dis(rng); });
+  }
+
+  const double& operator()() {
+    ++ptr_;
+    if (ptr_ == base_t::data() + N) ptr_ = base_t::data();
+    return *ptr_;
+  }
+
+  const double* ptr_ = base_t::data() - 1;
+};