ceph/src/boost/libs/compute/perf/perf_stl_find.cpp

   1 //---------------------------------------------------------------------------//
   2 // Copyright (c) 2015 Jakub Szuppe <j.szuppe@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 #include <algorithm>
  12 #include <iostream>
  13 #include <vector>
  14
  15 #include "perf.hpp"
  16
  17 // Max integer that can be generated by rand_int() function.
  18 int rand_int_max = 25;
  19
  20 int rand_int()
  21 {
  22     return static_cast<int>((rand() / double(RAND_MAX)) * rand_int_max);
  23 }
  24
  25 int main(int argc, char *argv[])
  26 {
  27     perf_parse_args(argc, argv);
  28     std::cout << "size: " << PERF_N << std::endl;
  29
  30     // create vector of random numbers on the host
  31     std::vector<int> host_vector(PERF_N);
  32     std::generate(host_vector.begin(), host_vector.end(), rand_int);
  33
  34     // trying to find element that isn't in vector (worst-case scenario)
  35     int wanted = rand_int_max + 1;
  36
  37     // result
  38     std::vector<int>::iterator host_result_it;
  39
  40     perf_timer t;
  41     for(size_t trial = 0; trial < PERF_TRIALS; trial++){
  42         t.start();
  43         host_result_it = std::find(host_vector.begin(), host_vector.end(), wanted);
  44         t.stop();
  45     }
  46     std::cout << "time: " << t.min_time() / 1e6 << " ms" << std::endl;
  47
  48     // verify
  49     if(host_result_it != host_vector.end()){
  50         std::cout << "ERROR: "
  51                   << "host_result_iterator != "
  52                   << "host_vector.end()"
  53                   << std::endl;
  54         return -1;
  55     }
  56
  57     return 0;
  58 }