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/*
Copyright 2005-2008 Intel Corporation. All Rights Reserved.
This file is part of Threading Building Blocks.
Threading Building Blocks is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License
version 2 as published by the Free Software Foundation.
Threading Building Blocks is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty
of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Threading Building Blocks; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
As a special exception, you may use this file as part of a free software
library without restriction. Specifically, if other files instantiate
templates or use macros or inline functions from this file, or you compile
this file and link it with other files to produce an executable, this
file does not by itself cause the resulting executable to be covered by
the GNU General Public License. This exception does not however
invalidate any other reasons why the executable file might be covered by
the GNU General Public License.
*/
#include <iostream>
#include <string>
#include <algorithm>
#include "tbb/task_scheduler_init.h"
#include "tbb/parallel_for.h"
#include "tbb/blocked_range.h"
#include "tbb/tick_count.h"
using namespace tbb;
using namespace std;
static const size_t N = 22;
void SerialSubStringFinder ( const string &str, size_t *max_array, size_t *pos_array) {
for ( size_t i = 0; i < str.size(); ++i ) {
size_t max_size = 0, max_pos = 0;
for (size_t j = 0; j < str.size(); ++j)
if (j != i) {
size_t limit = str.size()-( i > j ? i : j );
for (size_t k = 0; k < limit; ++k) {
if (str[i + k] != str[j + k]) break;
if (k > max_size) {
max_size = k;
max_pos = j;
}
}
}
max_array[i] = max_size;
pos_array[i] = max_pos;
}
}
class SubStringFinder {
const string str;
size_t *max_array;
size_t *pos_array;
public:
void operator() ( const blocked_range<size_t>& r ) const {
for ( size_t i = r.begin(); i != r.end(); ++i ) {
size_t max_size = 0, max_pos = 0;
for (size_t j = 0; j < str.size(); ++j)
if (j != i) {
size_t limit = str.size()-( i > j ? i : j );
for (size_t k = 0; k < limit; ++k) {
if (str[i + k] != str[j + k]) break;
if (k > max_size) {
max_size = k;
max_pos = j;
}
}
}
max_array[i] = max_size;
pos_array[i] = max_pos;
}
}
SubStringFinder(string &s, size_t *m, size_t *p) :
str(s), max_array(m), pos_array(p) { }
};
int main(size_t argc, char *argv[]) {
task_scheduler_init init;
string str[N] = { string("a"), string("b") };
for (size_t i = 2; i < N; ++i) str[i] = str[i-1]+str[i-2];
string &to_scan = str[N-1];
size_t *max = new size_t[to_scan.size()];
size_t *max2 = new size_t[to_scan.size()];
size_t *pos = new size_t[to_scan.size()];
size_t *pos2 = new size_t[to_scan.size()];
cout << " Done building string." << endl;
tick_count serial_t0 = tick_count::now();
SerialSubStringFinder(to_scan, max2, pos2);
tick_count serial_t1 = tick_count::now();
cout << " Done with serial version." << endl;
tick_count parallel_t0 = tick_count::now();
parallel_for(blocked_range<size_t>(0, to_scan.size(), 100),
SubStringFinder( to_scan, max, pos ) );
tick_count parallel_t1 = tick_count::now();
cout << " Done with parallel version." << endl;
for (size_t i = 0; i < to_scan.size(); ++i) {
if (max[i] != max2[i] || pos[i] != pos2[i]) {
cout << "ERROR: Serial and Parallel Results are Different!" << endl;
}
}
cout << " Done validating results." << endl;
cout << "Serial version ran in " << (serial_t1 - serial_t0).seconds() << " seconds" << endl
<< "Parallel version ran in " << (parallel_t1 - parallel_t0).seconds() << " seconds" << endl
<< "Resulting in a speedup of " << (serial_t1 - serial_t0).seconds() / (parallel_t1 - parallel_t0).seconds() << endl;
return 0;
}
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