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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 #include <algorithm>
12 #include <iostream>
13 #include <numeric>
14 #include <vector>
15 
16 #include <tbb/blocked_range.h>
17 #include <tbb/parallel_reduce.h>
18 
19 #include "perf.hpp"
20 
rand_int()21 int rand_int()
22 {
23     return static_cast<int>((rand() / double(RAND_MAX)) * 25.0);
24 }
25 
26 template<class T>
27 struct Sum {
28     T value;
SumSum29     Sum() : value(0) {}
SumSum30     Sum( Sum& s, tbb::split ) {value = 0;}
operator ()Sum31     void operator()( const tbb::blocked_range<T*>& r ) {
32         T temp = value;
33         for( T* a=r.begin(); a!=r.end(); ++a ) {
34             temp += *a;
35         }
36         value = temp;
37     }
joinSum38     void join( Sum& rhs ) {value += rhs.value;}
39 };
40 
41 template<class T>
ParallelSum(T array[],size_t n)42 T ParallelSum( T array[], size_t n ) {
43     Sum<T> total;
44     tbb::parallel_reduce( tbb::blocked_range<T*>( array, array+n ),
45                      total );
46     return total.value;
47 }
48 
main(int argc,char * argv[])49 int main(int argc, char *argv[])
50 {
51     perf_parse_args(argc, argv);
52     std::cout << "size: " << PERF_N << std::endl;
53 
54     // create vector of random numbers on the host
55     std::vector<int> host_vector(PERF_N);
56     std::generate(host_vector.begin(), host_vector.end(), rand_int);
57 
58     int sum = 0;
59     perf_timer t;
60     for(size_t trial = 0; trial < PERF_TRIALS; trial++){
61         t.start();
62         sum = ParallelSum<int>(&host_vector[0], host_vector.size());
63         t.stop();
64     }
65     std::cout << "time: " << t.min_time() / 1e6 << " ms" << std::endl;
66     std::cout << "sum: " << sum << std::endl;
67 
68     int host_sum = std::accumulate(host_vector.begin(), host_vector.end(), int(0));
69     if(sum != host_sum){
70         std::cerr << "ERROR: sum (" << sum << ") != (" << host_sum << ")" << std::endl;
71         return -1;
72     }
73 
74     return 0;
75 }
76