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- // spreadsort double sorting example.
- //
- // Copyright Steven Ross 2009-2014.
- //
- // 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://www.boost.org/libs/sort for library home page.
- #include <boost/sort/spreadsort/spreadsort.hpp>
- #include <time.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <algorithm>
- #include <vector>
- #include <string>
- #include <fstream>
- #include <iostream>
- using namespace boost::sort::spreadsort;
- #define DATA_TYPE double
- #define CAST_TYPE boost::int64_t
- //Pass in an argument to test std::sort
- //Note that this converts NaNs and -0.0 to 0.0, so that sorting results are
- //identical every time
- int main(int argc, const char ** argv) {
- size_t uCount,uSize=sizeof(DATA_TYPE);
- bool stdSort = false;
- unsigned loopCount = 1;
- for (int u = 1; u < argc; ++u) {
- if (std::string(argv[u]) == "-std")
- stdSort = true;
- else
- loopCount = atoi(argv[u]);
- }
- std::ifstream input("input.txt", std::ios_base::in | std::ios_base::binary);
- if (input.fail()) {
- printf("input.txt could not be opened\n");
- return 1;
- }
- double total = 0.0;
- std::vector<DATA_TYPE> array;
- input.seekg (0, std::ios_base::end);
- size_t length = input.tellg();
- uCount = length/uSize;
- //Using this to support compilers that don't support 64-bit constants
- CAST_TYPE exponent_mask = 0x7ff00000;
- exponent_mask <<= 32;
- CAST_TYPE top_exponent_bit = 0x40000000;
- top_exponent_bit <<= 32;
- //Run multiple loops, if requested
- for (unsigned u = 0; u < loopCount; ++u) {
- input.seekg (0, std::ios_base::beg);
- //Conversion to a vector
- array.resize(uCount);
- unsigned v = 0;
- while (input.good() && v < uCount) {
- input.read(reinterpret_cast<char *>(&(array[v])), uSize );
- //Checking for denormalized numbers
- if (!(float_mem_cast<DATA_TYPE, CAST_TYPE>(array[v]) & exponent_mask)) {
- //Make the top exponent bit high
- CAST_TYPE temp = top_exponent_bit |
- float_mem_cast<DATA_TYPE, CAST_TYPE>(array[v]);
- memcpy(&(array[v]), &temp, sizeof(DATA_TYPE));
- }
- //Testcase doesn't sort NaNs; they just cause confusion
- if (!(array[v] < 0.0) && !(0.0 < array[v]))
- array[v] = 0.0;
- ++v;
- }
- clock_t start, end;
- double elapsed;
- start = clock();
- if (stdSort)
- //std::sort(&(array[0]), &(array[0]) + uCount);
- std::sort(array.begin(), array.end());
- else
- //float_sort(&(array[0]), &(array[0]) + uCount);
- float_sort(array.begin(), array.end());
- end = clock();
- elapsed = static_cast<double>(end - start) ;
- std::ofstream ofile;
- if (stdSort)
- ofile.open("standard_sort_out.txt", std::ios_base::out |
- std::ios_base::binary | std::ios_base::trunc);
- else
- ofile.open("boost_sort_out.txt", std::ios_base::out |
- std::ios_base::binary | std::ios_base::trunc);
- if (ofile.good()) {
- for (unsigned v = 0; v < array.size(); ++v) {
- ofile.write(reinterpret_cast<char *>(&(array[v])), sizeof(array[v]) );
- }
- ofile.close();
- }
- total += elapsed;
- array.clear();
- }
- if (stdSort)
- printf("std::sort elapsed time %f\n", total / CLOCKS_PER_SEC);
- else
- printf("spreadsort elapsed time %f\n", total / CLOCKS_PER_SEC);
- return 0;
- }
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