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/** @file exam_collect.cpp
*
*/
/*
* GiNaC Copyright (C) 1999-2026 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, see <https://www.gnu.org/licenses/>.
*/
#include "ginac.h"
using namespace GiNaC;
#include <iostream>
using namespace std;
// Correctness of .collect(Z[x], x).
static unsigned exam_collect_1()
{
unsigned result = 0;
symbol x("x"), y("y");
ex a = (pow(x, 3) - 2*pow(x, 2) + 4*x) * pow(y, 2)
+ (pow(x, 2) - x - 1) * y
+ (x + 1);
ex b = pow(y, 2) * pow(x, 3)
+ (y - 2*pow(y, 2)) * pow(x, 2)
+ (4*pow(y, 2) - y + 1) * x
+ (1 - y);
ex a_x = collect(a, x);
if (a_x != b) {
clog << "collect(" << a << ", " << x << ") erroneously returned "
<< a_x << " instead of " << b << endl;
++result;
}
ex b_y = collect(b, y);
if (b_y != a) {
clog << "collect(" << b << ", " << y << ") erroneously returned "
<< b_y << " instead of " << a << endl;
++result;
}
ex amb_x = collect(a - b, x);
if (amb_x != 0) {
clog << "collect(" << a - b << ", " << x << ") erroneously returned "
<< amb_x << " instead of 0" << endl;
++result;
}
ex amb_y = collect(a - b, y);
if (amb_y != 0) {
clog << "collect(" << a - b << ", " << y << ") erroneously returned "
<< amb_y << " instead of 0" << endl;
++result;
}
return result;
}
// Consistency of .collect(Z[x,y], {x,y}) with .coeff(x).
static unsigned exam_collect_2()
{
unsigned result = 0;
symbol x("x"), y("y"), p("p"), q("q");
ex e1 = x + y;
ex e2 = 1 + p + q;
ex a = expand(e1 * e2);
ex a_x = a.collect(x).coeff(x, 1);
if (a_x != e2) {
clog << "collect(" << a << ", " << x << ") erroneously returned "
<< a_x << " as coefficient of " << x << endl;
++result;
}
ex a_p = a.collect(p).coeff(p, 1);
if (a_p != e1) {
clog << "collect(" << a << ", " << p << ") erroneously returned "
<< a_p << " as coefficient of " << p << endl;
++result;
}
ex a_xy = a.collect(lst{x,y});
ex ref = e2*x + e2*y;
if (a_xy != ref) {
clog << "collect(" << a << ", {" << x << ", " << y << "}) erroneously returned "
<< a_xy << " instead of " << ref << endl;
++result;
}
return result;
}
// Consistency of .collect(Z[f(x)], f(x)) with .coeff(f(x)).
static unsigned exam_collect_3()
{
unsigned result = 0;
symbol x("x"), p("p"), q("q");
for (unsigned deg = 2; deg < 7; ++deg) {
ex a1 = expand(pow(p + q + x, deg));
a1 = a1.collect(x);
ex a2 = expand(pow(p + q + sin(x), deg));
a2 = a2.collect(sin(x));
for (unsigned i = 0; i < deg; ++i) {
ex a1_i = a1.coeff(x, i);
ex a2_i = a2.coeff(sin(x), i);
if (!expand(a1_i - a2_i).is_zero()) {
clog << "collect(" << a1 << ",sin(x)) inconsistent with "
"collect(" << a2 << ",x)" << endl;
++result;
}
}
}
return result;
}
unsigned exam_collect()
{
unsigned result = 0;
cout << "examining collect coefficients" << flush;
result += exam_collect_1(); cout << '.' << flush;
result += exam_collect_2(); cout << '.' << flush;
result += exam_collect_3(); cout << '.' << flush;
return result;
}
int main(int argc, char** argv)
{
return exam_collect();
}
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