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/** @file randomize_serials.cpp
*
* Utilitiy function used by the benchmarks.
*/
/*
* GiNaC Copyright (C) 1999-2010 Johannes Gutenberg University Mainz, Germany
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "ginac.h"
using namespace GiNaC;
#include <cstdlib>
#include <ctime>
using namespace std;
/** Generate a random amount of symbols and destroy them again immediatly.
* This operation effectively makes the serial numbers of all subsequent
* symbols unpredictable. If the serials are unpredictable, then so are
* their hash values. If the hash values are unpredictable, then so are
* the canonical orderings. If the canonical orderings are unpredictable,
* all subsequent times are subject to some variation. This variation,
* however is natural and desireable for two reasons: First, we cannot know
* how many symbols have been generated before in real world computations.
* Second, the following timings are subject to some semi-random variation
* anyways because short timings need to be repeated until enough time has
* gone by for the measurement to be reliable. During this process the serial
* numbers will be shifted anyways in a semi-random way. It is better not
* to lull the user in a false sense of reproducibility and instead confront
* her with the normal variation to be expected.
*/
void randomify_symbol_serials()
{
srand(time(NULL));
const int m = rand() % 666;
for (int s=0; s<m; ++s ) {
symbol("dummy");
}
}
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