1 //---------------------------------------------------------------------------//
2 // Copyright (c) 2013-2014 Rastko Anicic <anicic.rastko@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 <boost/compute/system.hpp>
16 #include <boost/compute/algorithm/max_element.hpp>
17 #include <boost/compute/container/vector.hpp>
18 
19 #include "perf.hpp"
20 
rand_int()21 int rand_int()
22 {
23     return static_cast<int>(rand() % 10000000);
24 }
25 
main(int argc,char * argv[])26 int main(int argc, char *argv[])
27 {
28     perf_parse_args(argc, argv);
29     std::cout << "size: " << PERF_N << std::endl;
30 
31     // setup context and queue for the default device
32     boost::compute::device device = boost::compute::system::default_device();
33     boost::compute::context context(device);
34     boost::compute::command_queue queue(context, device);
35     std::cout << "device: " << device.name() << std::endl;
36 
37     // create vector of random numbers on the host
38     std::vector<int> host_vector(PERF_N);
39     std::generate(host_vector.begin(), host_vector.end(), rand_int);
40 
41     // create vector on the device and copy the data
42     boost::compute::vector<int> device_vector(PERF_N, context);
43     boost::compute::copy(
44         host_vector.begin(),
45         host_vector.end(),
46         device_vector.begin(),
47         queue
48     );
49 
50     boost::compute::vector<int>::iterator device_max_iter
51         = device_vector.begin();
52 
53     perf_timer t;
54     for(size_t trial = 0; trial < PERF_TRIALS; trial++){
55         t.start();
56         device_max_iter = boost::compute::max_element(
57             device_vector.begin(), device_vector.end(), queue
58         );
59         queue.finish();
60         t.stop();
61     }
62 
63     int device_max = device_max_iter.read(queue);
64     std::cout << "time: " << t.min_time() / 1e6 << " ms" << std::endl;
65     std::cout << "max: " << device_max << std::endl;
66 
67     // verify max is correct
68     std::vector<int>::iterator host_max_iter
69         = std::max_element(host_vector.begin(), host_vector.end());
70 
71     int host_max = *host_max_iter;
72     if(device_max != host_max){
73          std::cout << "ERROR: "
74                    << "device_max (" << device_max << ") "
75                    << "!= "
76                    << "host_max (" << host_max << ")"
77                    << std::endl;
78          return -1;
79     }
80 
81     size_t host_max_idx = std::distance(host_vector.begin(), host_max_iter);
82     size_t device_max_idx = std::distance(device_vector.begin(), device_max_iter);
83     if(device_max_idx != host_max_idx){
84         std::cout << "ERROR: "
85                   << "device_max index (" << device_max_idx << ") "
86                   << "!= "
87                   << "host_max index (" << host_max_idx << ")"
88                   << std::endl;
89         return -1;
90     }
91 
92     return 0;
93 }
94