{

// get the default device

compute::device gpu = compute::system::default_device();

// create context for default device

compute::context context(gpu);

// create command queue with profiling enabled

compute::command_queue queue(

context, gpu, compute::command_queue::enable_profiling

);

// generate random data on the host

std::vector<int> host_vector(16000000);

std::generate(host_vector.begin(), host_vector.end(), rand);

// create a vector on the device

compute::vector<int> device_vector(host_vector.size(), context);

// copy data from the host to the device

compute::future<void> future = compute::copy_async(

host_vector.begin(), host_vector.end(), device_vector.begin(), queue

);

// wait for copy to finish

future.wait();

// get elapsed time from event profiling information

boost::chrono::milliseconds duration =

future.get_event().duration<boost::chrono::milliseconds>();

// print elapsed time in milliseconds

std::cout << "time: " << duration.count() << " ms" << std::endl;

return 0;