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
13 #include <boost/compute/core.hpp>
14
15 namespace compute = boost::compute;
16
17 // this example demonstrates how to use the Boost.Compute classes to
18 // setup and run a simple vector addition kernel on the GPU
main()19 int main()
20 {
21 // get the default device
22 compute::device device = compute::system::default_device();
23
24 // create a context for the device
25 compute::context context(device);
26
27 // setup input arrays
28 float a[] = { 1, 2, 3, 4 };
29 float b[] = { 5, 6, 7, 8 };
30
31 // make space for the output
32 float c[] = { 0, 0, 0, 0 };
33
34 // create memory buffers for the input and output
35 compute::buffer buffer_a(context, 4 * sizeof(float));
36 compute::buffer buffer_b(context, 4 * sizeof(float));
37 compute::buffer buffer_c(context, 4 * sizeof(float));
38
39 // source code for the add kernel
40 const char source[] =
41 "__kernel void add(__global const float *a,"
42 " __global const float *b,"
43 " __global float *c)"
44 "{"
45 " const uint i = get_global_id(0);"
46 " c[i] = a[i] + b[i];"
47 "}";
48
49 // create the program with the source
50 compute::program program =
51 compute::program::create_with_source(source, context);
52
53 // compile the program
54 program.build();
55
56 // create the kernel
57 compute::kernel kernel(program, "add");
58
59 // set the kernel arguments
60 kernel.set_arg(0, buffer_a);
61 kernel.set_arg(1, buffer_b);
62 kernel.set_arg(2, buffer_c);
63
64 // create a command queue
65 compute::command_queue queue(context, device);
66
67 // write the data from 'a' and 'b' to the device
68 queue.enqueue_write_buffer(buffer_a, 0, 4 * sizeof(float), a);
69 queue.enqueue_write_buffer(buffer_b, 0, 4 * sizeof(float), b);
70
71 // run the add kernel
72 queue.enqueue_1d_range_kernel(kernel, 0, 4, 0);
73
74 // transfer results back to the host array 'c'
75 queue.enqueue_read_buffer(buffer_c, 0, 4 * sizeof(float), c);
76
77 // print out results in 'c'
78 std::cout << "c: [" << c[0] << ", "
79 << c[1] << ", "
80 << c[2] << ", "
81 << c[3] << "]" << std::endl;
82
83 return 0;
84 }
85