Initial commit

libs/math/performance/bernoulli_performance.cpp

@@ -0,0 +1,79 @@
+//  (C) Copyright John Maddock 2013.
+//  Use, modification and distribution are subject to 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 <boost/math/special_functions/bernoulli.hpp>
+#include <boost/chrono.hpp>
+#include <boost/multiprecision/cpp_dec_float.hpp>
+
+template <class Clock>
+struct stopwatch
+{
+   typedef typename Clock::duration duration;
+   stopwatch()
+   {
+      m_start = Clock::now();
+   }
+   duration elapsed()
+   {
+      return Clock::now() - m_start;
+   }
+   void reset()
+   {
+      m_start = Clock::now();
+   }
+
+private:
+   typename Clock::time_point m_start;
+};
+
+void time()
+{
+   stopwatch<boost::chrono::high_resolution_clock> w;
+   //
+   // Sum the first 1000 Bernoulli numbers:
+   //
+   boost::multiprecision::cpp_dec_float_50 sum = 0;
+   for(unsigned i = 0; i < 1000; ++i)
+   {
+      sum += boost::math::bernoulli_b2n<boost::multiprecision::cpp_dec_float_50>(i);
+   }
+   double t = boost::chrono::duration_cast<boost::chrono::duration<double> >(w.elapsed()).count();
+   std::cout << "Total execution time = " << std::setprecision(3) << t << "s" << std::endl;
+   std::cout << "Sum was: " << sum << std::endl;
+}
+
+int main()
+{
+   // Call time() twice: first call results in the cache being populated, second used already cached values:
+   time();
+   time();
+   return 0;
+}
+
+/*
+
+No atomic int:
+
+Total execution time = 0.646s
+Sum was: 2.86e+4134
+Total execution time = 0.000341s
+Sum was: 2.86e+4134
+
+With atomic int:
+
+Total execution time = 0.643s
+Sum was: 2.86e+4134
+Total execution time = 0.000309s
+Sum was: 2.86e+4134
+
+No threads:
+
+Total execution time = 0.652s
+Sum was: 2.86e+4134
+Total execution time = 0.000281s
+Sum was: 2.86e+4134
+
+*/
+