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/** @file exam_misc.cpp
*
* Testing modular GCD.
*/
/*
* GiNaC Copyright (C) 1999-2025 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 <cln/random.h>
#include <iostream>
#include <map>
#include <string>
#include "polynomial/upoly.h"
#include "polynomial/upoly_io.h"
#include "polynomial/mod_gcd.h"
#include "ginac.h"
using namespace GiNaC;
static upoly ex_to_upoly(const ex& e, const symbol& x);
static ex upoly_to_ex(const upoly& p, const symbol& x);
// make a univariate polynomial \in Z[x] of degree deg
static upoly make_random_upoly(const std::size_t deg);
static void run_test_once(const std::size_t deg)
{
static const symbol xsym("x");
const upoly a = make_random_upoly(deg);
const upoly b = make_random_upoly(deg);
upoly g;
mod_gcd(g, a, b);
ex ea = upoly_to_ex(a, xsym);
ex eb = upoly_to_ex(b, xsym);
ex eg = gcd(ea, eb);
const upoly g_check = ex_to_upoly(eg, xsym);
if (g != g_check) {
std::cerr << "a = " << a << std::endl;
std::cerr << "b = " << b << std::endl;
std::cerr << "mod_gcd(a, b) = " << g << std::endl;
std::cerr << "sr_gcd(a, b) = " << g_check << std::endl;
throw std::logic_error("bug in mod_gcd");
}
}
int main(int argc, char** argv)
{
std::cout << "examining modular gcd. ";
std::map<std::size_t, std::size_t> n_map;
// run 256 tests with polynomials of degree 10
n_map[10] = 256;
// run 32 tests with polynomials of degree 100
n_map[100] = 32;
std::map<std::size_t, std::size_t>::const_iterator i = n_map.begin();
for (; i != n_map.end(); ++i) {
for (std::size_t k = 0; k < i->second; ++k)
run_test_once(i->first);
}
return 0;
}
static upoly ex_to_upoly(const ex& e, const symbol& x)
{
upoly p(e.degree(x) + 1);
for (int i = 0; i <= e.degree(x); ++i)
p[i] = cln::the<cln::cl_I>(ex_to<numeric>(e.coeff(x, i)).to_cl_N());
return p;
}
static ex upoly_to_ex(const upoly& p, const symbol& x)
{
exvector tv(p.size());
for (std::size_t i = 0; i < p.size(); ++i)
tv[i] = pow(x, i)*numeric(p[i]);
return dynallocate<add>(tv);
}
static upoly make_random_upoly(const std::size_t deg)
{
static const cln::cl_I biggish("98765432109876543210");
upoly p(deg + 1);
for (std::size_t i = 0; i <= deg; ++i)
p[i] = cln::random_I(biggish);
// Make sure the leading coefficient is non-zero
while (zerop(p[deg]))
p[deg] = cln::random_I(biggish);
return p;
}
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