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/** @file time_dennyfliegner.cpp
*
* The first test routine implements Denny Fliegner's quick consistency check:
* 1) e = (a0 + a1 + a2 + a3 + ...)^2, in expanded form
* 2) substitute a0 by (-a2 - a3 - ...) in e
* 3) expand e
* after which e should be just a1^2. */
/*
* 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"
#include "timer.h"
using namespace GiNaC;
#include <iostream>
#include <sstream>
#include <vector>
using namespace std;
static unsigned expand_subs(unsigned size)
{
unsigned result = 0;
// create a vector of size symbols named "a0", "a1", ...
vector<symbol> a;
ex e;
for (unsigned i=0; i<size; ++i) {
ostringstream buf;
buf << "a" << i << ends;
a.push_back(symbol(buf.str()));
e += a[i];
}
ex aux;
// prepare aux so it will swallow anything but a1^2:
aux = -e + a[0] + a[1];
e = pow(e,2).expand().subs(a[0]==aux, subs_options::no_pattern).expand();
if (e != pow(a[1],2)) {
clog << "Denny Fliegner's quick consistency check erroneously returned "
<< e << "." << endl;
++result;
}
return result;
}
unsigned time_dennyfliegner()
{
unsigned result = 0;
cout << "timing commutative expansion and substitution" << flush;
vector<unsigned> sizes;
vector<double> times;
timer breitling;
sizes.push_back(100);
sizes.push_back(200);
sizes.push_back(400);
sizes.push_back(800);
for (vector<unsigned>::iterator i=sizes.begin(); i!=sizes.end(); ++i) {
breitling.start();
result += expand_subs(*i);
times.push_back(breitling.read());
cout << '.' << flush;
}
// print the report:
cout << endl << " size: ";
for (vector<unsigned>::iterator i=sizes.begin(); i!=sizes.end(); ++i)
cout << '\t' << *i;
cout << endl << " time/s:";
for (vector<double>::iterator i=times.begin(); i!=times.end(); ++i)
cout << '\t' << *i;
cout << endl;
return result;
}
extern void randomify_symbol_serials();
int main(int argc, char** argv)
{
randomify_symbol_serials();
cout << setprecision(2) << showpoint;
return time_dennyfliegner();
}
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