88 lines
2.9 KiB
C++
88 lines
2.9 KiB
C++
//---------------------------------------------------------------------------//
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// Copyright (c) 2014 Kyle Lutz <kyle.r.lutz@gmail.com>
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//
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// Distributed under the Boost Software License, Version 1.0
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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// See http://boostorg.github.com/compute for more information.
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//---------------------------------------------------------------------------//
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#include <iostream>
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#include <boost/compute/system.hpp>
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#include <boost/compute/algorithm/copy.hpp>
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#include <boost/compute/algorithm/copy_n.hpp>
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#include <boost/compute/algorithm/find_if.hpp>
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#include <boost/compute/container/vector.hpp>
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#include <boost/compute/iterator/zip_iterator.hpp>
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namespace compute = boost::compute;
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// this example shows how to use the find_if() algorithm to detect the
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// point at which two vectors of prices (such as stock prices) cross.
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int main()
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{
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// get default device and setup context
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compute::device gpu = compute::system::default_device();
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compute::context context(gpu);
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compute::command_queue queue(context, gpu);
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// prices #1 (from 10.0 to 11.0)
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std::vector<float> prices1;
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for(float i = 10.0; i <= 11.0; i += 0.1){
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prices1.push_back(i);
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}
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// prices #2 (from 11.0 to 10.0)
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std::vector<float> prices2;
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for(float i = 11.0; i >= 10.0; i -= 0.1){
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prices2.push_back(i);
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}
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// create gpu vectors
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compute::vector<float> gpu_prices1(prices1.size(), context);
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compute::vector<float> gpu_prices2(prices2.size(), context);
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// copy prices to gpu
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compute::copy(prices1.begin(), prices1.end(), gpu_prices1.begin(), queue);
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compute::copy(prices2.begin(), prices2.end(), gpu_prices2.begin(), queue);
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// function returning true if the second price is less than the first price
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BOOST_COMPUTE_FUNCTION(bool, check_price_cross, (boost::tuple<float, float> prices),
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{
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// first price
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const float first = boost_tuple_get(prices, 0);
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// second price
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const float second = boost_tuple_get(prices, 1);
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// return true if second price is less than first
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return second < first;
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});
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// find cross point (should be 10.5)
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compute::vector<float>::iterator iter = boost::get<0>(
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compute::find_if(
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compute::make_zip_iterator(
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boost::make_tuple(gpu_prices1.begin(), gpu_prices2.begin())
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),
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compute::make_zip_iterator(
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boost::make_tuple(gpu_prices1.end(), gpu_prices2.end())
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),
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check_price_cross,
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queue
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).get_iterator_tuple()
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);
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// print out result
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int index = std::distance(gpu_prices1.begin(), iter);
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std::cout << "price cross at index: " << index << std::endl;
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float value;
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compute::copy_n(iter, 1, &value, queue);
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std::cout << "value: " << value << std::endl;
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return 0;
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}
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