/** @file paranoia_check.cpp
*
* This set of tests checks for some of GiNaC's oopses which showed up during
* development. Things were evaluated wrongly and so. Such a sick behaviour
* shouldn't occur any more. But we are paranoic and we want to exclude these
* these oopses for good, so we run those stupid tests... */
/*
* GiNaC Copyright (C) 1999-2000 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "ginac.h"
#ifndef NO_NAMESPACE_GINAC
using namespace GiNaC;
#endif // ndef NO_NAMESPACE_GINAC
// The very first pair of historic problems had its roots in power.cpp and was
// finally resolved on April 27th 1999. (Fixing the first on April 23rd
// actually introduced the second.)
static unsigned paranoia_check1(void)
{
unsigned result = 0;
symbol x("x"), y("y"), z("z");
ex e, f, g;
e = x * y * z;
f = y * z;
g = e / f;
// In the first one expand did not do any job at all:
if (!g.expand().is_equal(x)) {
clog << "e = x*y*z; f = y*z; expand(e/f) erroneously returned "
<< g.expand() << endl;
++result;
}
// This one somehow used to return 0:
e = pow(x + 1, -1);
if (!e.expand().is_equal(e)) {
clog << "expand(pow(x + 1, -1)) erroneously returned "
<< e.expand() << endl;
++result;
}
return result;
}
// And here the second oops which showed up until May 17th 1999. It had to do
// with lexicographic canonicalization and thus showed up only if the variables
// had the names as given here:
static unsigned paranoia_check2(void)
{
unsigned result = 0;
symbol x("x"), y("y"), z("z");
ex e, f, g;
e = x + z*x;
f = e*y;
g = f - e*y;
// After .expand(), g should be zero:
if (!g.expand().is_zero()) {
clog << "e = (x + z*x); f = e*y; expand(f - e*y) erroneously returned "
<< g.expand() << endl;
++result;
}
// After .eval(), g should be zero:
if (!g.eval().is_zero()) {
clog << "e = (x + z*x); f = e*y; eval(f - e*y) erroneously returned "
<< g.eval() << endl;
++result;
}
// This actually worked already back in April 1999.
// But we are *very* paranoic!
if (!g.expand().eval().is_zero()) {
clog << "e = (x + z*x); f = e*y; eval(expand(f - e*y)) erroneously returned "
<< g.expand().eval() << endl;
++result;
}
return result;
}
// The third bug was introduced on May 18th 1999, discovered on May 19 and
// fixed that same day. It worked when x was substituted by 1 but not with
// other numbers:
static unsigned paranoia_check3(void)
{
unsigned result = 0;
symbol x("x"), y("y");
ex e, f;
e = x*y - y;
f = e.subs(x == 2);
if (!f.is_equal(y)) {
clog << "e = x*y - y; f = e.subs(x == 2) erroneously returned "
<< f << endl;
++result;
}
if (!f.eval().is_equal(y)) {
clog << "e = x*y - y; eval(e.subs(x == 2)) erroneously returned "
<< f.eval() << endl;
++result;
}
if (!f.expand().is_equal(y)) {
clog << "e = x*y - y; expand(e.subs(x == 2)) erroneously returned "
<< f.expand() << endl;
++result;
}
return result;
}
// The fourth bug was also discovered on May 19th 1999 and fixed immediately:
static unsigned paranoia_check4(void)
{
unsigned result = 0;
symbol x("x");
ex e, f, g;
e = pow(x, 2) + x + 1;
f = pow(x, 2) + x + 1;
g = e - f;
if (!g.is_zero()) {
clog << "e = pow(x,2) + x + 1; f = pow(x,2) + x + 1; g = e-f; g erroneously returned "
<< g << endl;
++result;
}
if (!g.is_zero()) {
clog << "e = pow(x,2) + x + 1; f = pow(x,2) + x + 1; g = e-f; g.eval() erroneously returned "
<< g.eval() << endl;
++result;
}
return result;
}
// The fifth oops was discovered on May 20th 1999 and fixed a day later:
static unsigned paranoia_check5(void)
{
unsigned result = 0;
symbol x("x"), y("y");
ex e, f;
e = pow(x*y + 1, 2);
f = pow(x, 2) * pow(y, 2) + 2*x*y + 1;
if (!(e-f).expand().is_zero()) {
clog << "e = pow(x*y+1,2); f = pow(x,2)*pow(y,2) + 2*x*y + 1; (e-f).expand() erroneously returned "
<< (e-f).expand() << endl;
++result;
}
return result;
}
// This one was discovered on Jun 1st 1999 and fixed the same day:
static unsigned paranoia_check6(void)
{
unsigned result = 0;
symbol x("x");
ex e, f;
e = pow(x, -5);
f = e.denom();
if (!f.is_equal(pow(x, 5))) {
clog << "e = pow(x, -5); f = e.denom(); f was " << f << " (should be x^5)" << endl;
++result;
}
return result;
}
// This one was introduced on June 1st 1999 by some aggressive manual
// optimization. Discovered and fixed on June 2nd.
static unsigned paranoia_check7(void)
{
unsigned result = 0;
symbol x("x"), y("y");
ex e = y + y*x + 2;
ex f = expand(pow(e, 2) - (e*y*(x + 1)));
if (f.nops() > 3) {
clog << "e=y+y*x+2; f=expand(pow(e,2)-(e*y*(x+1))) has "
<< f.nops() << " arguments instead of 3 ( f=="
<< f << " )" << endl;
++result;
}
return result;
}
// This one was a result of the rewrite of mul::max_coefficient when we
// introduced the overall_coefficient field in expairseq objects on Oct 1st
// 1999. Fixed on Oct 4th.
static unsigned paranoia_check8(void)
{
unsigned result = 0;
symbol x("x");
ex e = -x / (x+1);
ex f;
try {
f = e.normal();
if (!f.is_equal(e)) {
clog << "normal(-x/(x+1)) returns " << f << " instead of -x/(x+1)\n";
++result;
}
} catch (const exception &e) {
clog << "normal(-x/(x+1) throws " << e.what() << endl;
++result;
}
return result;
}
// This one was a result of a modification to frac_cancel() & Co. to avoid
// expanding the numerator and denominator when bringing them from Q[X] to
// Z[X]. multiply_lcm() forgot to multiply the x-linear term with the LCM of
// the coefficient's denominators (2 in this case). Introduced on Jan 25th
// 2000 and fixed on Jan 31th.
static unsigned paranoia_check9(void)
{
unsigned result = 0;
symbol x("x");
ex e = (exp(-x)-2*x*exp(-x)+pow(x,2)/2*exp(-x))/exp(-x);
ex f = e.normal();
if (!f.is_equal(1-2*x+pow(x,2)/2)) {
clog << "normal(" << e << ") returns " << f << " instead of 1-2*x+1/2*x^2\n";
++result;
}
return result;
}
// I have no idea when this broke. It has been working long ago, before 0.4.0
// and on Feb 13th 2000 I found out that things like 2^(3/2) throw an exception
// "power::eval(): pow(0,0) is undefined" instead of simplifying to 2*2^(1/2).
// It was fixed that same day.
static unsigned paranoia_check10(void)
{
unsigned result = 0;
ex b = numeric(2);
ex e = numeric(3,2);
ex r;
try {
r = pow(b,e).eval();
if (!(r-2*sqrt(ex(2))).is_zero()) {
clog << "2^(3/2) erroneously returned " << r << " instead of 2*sqrt(2)" << endl;
++result;
}
} catch (const exception &e) {
clog << "2^(3/2) throws " << e.what() << endl;
++result;
}
return result;
}
unsigned paranoia_check(void)
{
unsigned result = 0;
cout << "checking several ex-bugs just out of pure paranoia..." << flush;
clog << "---------several ex-bugs just out of pure paranoia:" << endl;
result += paranoia_check1();
result += paranoia_check2();
result += paranoia_check3();
result += paranoia_check4();
result += paranoia_check5();
result += paranoia_check6();
result += paranoia_check7();
result += paranoia_check8();
result += paranoia_check9();
result += paranoia_check10();
if (!result) {
cout << " passed ";
clog << "(no output)" << endl;
} else {
cout << " failed ";
}
return result;
}