// spreadsort float 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 float | |
#define CAST_TYPE int | |
//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; | |
//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<float, int>(array[v]) & 0x7f800000)) { | |
//Make the top exponent bit high | |
CAST_TYPE temp = 0x40000000 | float_mem_cast<float, int>(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 | |
//boost::sort::spreadsort::spreadsort(&(array[0]), &(array[0]) + uCount); | |
boost::sort::spreadsort::spreadsort(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(); | |
} | |
input.close(); | |
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; | |
} |