1 //---------------------------------------------------------------------------//
2 // Copyright (c) 2013 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 <iostream>
12 #include <iterator>
13
14 #include <boost/compute/algorithm/max_element.hpp>
15 #include <boost/compute/container/vector.hpp>
16 #include <boost/compute/functional/geometry.hpp>
17 #include <boost/compute/iterator/transform_iterator.hpp>
18 #include <boost/compute/types/fundamental.hpp>
19
20 namespace compute = boost::compute;
21
22 // this example shows how to use the max_element() algorithm along with
23 // a transform_iterator and the length() function to find the longest
24 // 4-component vector in an array of vectors
main()25 int main()
26 {
27 using compute::float4_;
28
29 // vectors data
30 float data[] = { 1.0f, 2.0f, 3.0f, 0.0f,
31 4.0f, 5.0f, 6.0f, 0.0f,
32 7.0f, 8.0f, 9.0f, 0.0f,
33 0.0f, 0.0f, 0.0f, 0.0f };
34
35 // create device vector with the vector data
36 compute::vector<float4_> vector(
37 reinterpret_cast<float4_ *>(data),
38 reinterpret_cast<float4_ *>(data) + 4
39 );
40
41 // find the longest vector
42 compute::vector<float4_>::const_iterator iter =
43 compute::max_element(
44 compute::make_transform_iterator(
45 vector.begin(), compute::length<float4_>()
46 ),
47 compute::make_transform_iterator(
48 vector.end(), compute::length<float4_>()
49 )
50 ).base();
51
52 // print the index of the longest vector
53 std::cout << "longest vector index: "
54 << std::distance(vector.begin(), iter)
55 << std::endl;
56
57 return 0;
58 }
59