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//---------------------------------------------------------------------------//
// Copyright (c) 2014 Benoit
//
// Distributed under the Boost Software License, Version 1.0
// See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt
//
// See http://boostorg.github.com/compute for more information.
//---------------------------------------------------------------------------//
#include <algorithm>
#include <iostream>
#include <numeric>
#include <vector>
#include <boost/compute/system.hpp>
#include <boost/compute/algorithm/exclusive_scan.hpp>
#include <boost/compute/container/vector.hpp>
#include "perf.hpp"
int rand_int()
{
return static_cast<int>((rand() / double(RAND_MAX)) * 25.0);
}
int main(int argc, char *argv[])
{
perf_parse_args(argc, argv);
std::cout << "size: " << PERF_N << std::endl;
// setup context and queue for the default device
boost::compute::device device = boost::compute::system::default_device();
boost::compute::context context(device);
boost::compute::command_queue queue(context, device);
std::cout << "device: " << device.name() << std::endl;
// create vector of random numbers on the host
std::vector<int> host_vector(PERF_N);
std::generate(host_vector.begin(), host_vector.end(), rand_int);
// create vector on the device and copy the data
boost::compute::vector<int> device_vector(PERF_N, context);
boost::compute::vector<int> device_res(PERF_N,context);
boost::compute::copy(
host_vector.begin(),
host_vector.end(),
device_vector.begin(),
queue
);
// sum vector
perf_timer t;
for(size_t trial = 0; trial < PERF_TRIALS; trial++){
boost::compute::copy(
host_vector.begin(),
host_vector.end(),
device_vector.begin(),
queue
);
t.start();
boost::compute::exclusive_scan(
device_vector.begin(),
device_vector.end(),
device_res.begin(),
queue
);
queue.finish();
t.stop();
}
std::cout << "time: " << t.min_time() / 1e6 << " ms" << std::endl;
// verify sum is correct
std::partial_sum(
host_vector.begin(),
host_vector.end(),
host_vector.begin()
);
int device_sum = device_res.back();
// when scan is exclusive values are shifted by one on the left
// compared to a inclusive scan
int host_sum = host_vector[host_vector.size()-2];
if(device_sum != host_sum){
std::cout << "ERROR: "
<< "device_sum (" << device_sum << ") "
<< "!= "
<< "host_sum (" << host_sum << ")"
<< std::endl;
return -1;
}
return 0;
}
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