ceph/src/boost/libs/compute/test/test_normal_distribution.cpp

   1 //---------------------------------------------------------------------------//
   2 // Copyright (c) 2013-2014 Kyle Lutz <kyle.r.lutz@gmail.com>
   3 //
   4 // Distributed under the Boost Software License, Version 1.0
   5 // See accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt
   7 //
   8 // See http://boostorg.github.com/compute for more information.
   9 //---------------------------------------------------------------------------//
  10
  11 #define BOOST_TEST_MODULE TestNormalDistribution
  12 #include <boost/test/unit_test.hpp>
  13
  14 #include <boost/compute/system.hpp>
  15 #include <boost/compute/command_queue.hpp>
  16 #include <boost/compute/algorithm/count_if.hpp>
  17 #include <boost/compute/container/vector.hpp>
  18 #include <boost/compute/random/default_random_engine.hpp>
  19 #include <boost/compute/random/normal_distribution.hpp>
  20 #include <boost/compute/lambda.hpp>
  21
  22 #include <boost/accumulators/accumulators.hpp>
  23 #include <boost/accumulators/statistics/mean.hpp>
  24 #include <boost/accumulators/statistics/stats.hpp>
  25 #include <boost/accumulators/statistics/variance.hpp>
  26
  27 #include "context_setup.hpp"
  28
  29 template<class Stats, class T>
  30 boost::accumulators::accumulator_set<T, Stats>
  31 accumulate_statistics(const boost::compute::vector<T>& vector,
  32                       boost::compute::command_queue& queue) {
  33     // copy vector to the host
  34     std::vector<T> host_vector(vector.size());
  35     boost::compute::copy(
  36         vector.begin(), vector.end(), host_vector.begin(), queue
  37     );
  38
  39     // compute desired statistics and return accumulator object
  40     return std::for_each(
  41         host_vector.begin(),
  42         host_vector.end(),
  43         boost::accumulators::accumulator_set<T, Stats>()
  44     );
  45 }
  46
  47 BOOST_AUTO_TEST_CASE(normal_distribution_doctest)
  48 {
  49     using boost::compute::lambda::_1;
  50
  51     boost::compute::vector<float> vec(10, context);
  52
  53 //! [generate]
  54 // initialize the default random engine
  55 boost::compute::default_random_engine engine(queue);
  56
  57 // setup the normal distribution to produce floats centered at 5
  58 boost::compute::normal_distribution<float> distribution(5.0f, 1.0f);
  59
  60 // generate the random values and store them to 'vec'
  61 distribution.generate(vec.begin(), vec.end(), engine, queue);
  62 //! [generate]
  63 }
  64
  65 BOOST_AUTO_TEST_CASE(normal_distribution_statistics)
  66 {
  67     // generate normally distributed random numbers
  68     const size_t n = 10000;
  69     boost::compute::vector<float> vec(n, context);
  70     boost::compute::default_random_engine engine(queue);
  71     boost::compute::normal_distribution<float> distribution(10.0f, 2.0f);
  72     distribution.generate(vec.begin(), vec.end(), engine, queue);
  73
  74     // compute mean and standard deviation
  75     using namespace boost::accumulators;
  76     accumulator_set<float, stats<tag::variance> > acc =
  77         accumulate_statistics<stats<tag::variance> >(vec, queue);
  78
  79     // check mean and standard deviation are what we expect
  80     BOOST_CHECK_CLOSE(mean(acc), 10.f, 0.5f);
  81     BOOST_CHECK_CLOSE(std::sqrt(variance(acc)), 2.f, 0.5f);
  82 }
  83
  84 BOOST_AUTO_TEST_SUITE_END()