1 /** @file paranoia_check.cpp
3 * This set of tests checks for some of GiNaC's oopses which showed up during
4 * development. Things were evaluated wrongly and so. Such a sick behaviour
5 * shouldn't occur any more. But we are paranoic and we want to exclude these
6 * these oopses for good, so we run those stupid tests... */
9 * GiNaC Copyright (C) 1999-2000 Johannes Gutenberg University Mainz, Germany
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
28 #ifndef NO_NAMESPACE_GINAC
29 using namespace GiNaC;
30 #endif // ndef NO_NAMESPACE_GINAC
32 // The very first pair of historic problems had its roots in power.cpp and was
33 // finally resolved on April 27th 1999. (Fixing the first on April 23rd
34 // actually introduced the second.)
35 static unsigned paranoia_check1(void)
38 symbol x("x"), y("y"), z("z");
45 // In the first one expand did not do any job at all:
46 if (!g.expand().is_equal(x)) {
47 clog << "e = x*y*z; f = y*z; expand(e/f) erroneously returned "
48 << g.expand() << endl;
52 // This one somehow used to return 0:
54 if (!e.expand().is_equal(e)) {
55 clog << "expand(pow(x + 1, -1)) erroneously returned "
56 << e.expand() << endl;
63 // And here the second oops which showed up until May 17th 1999. It had to do
64 // with lexicographic canonicalization and thus showed up only if the variables
65 // had the names as given here:
66 static unsigned paranoia_check2(void)
69 symbol x("x"), y("y"), z("z");
76 // After .expand(), g should be zero:
77 if (!g.expand().is_zero()) {
78 clog << "e = (x + z*x); f = e*y; expand(f - e*y) erroneously returned "
79 << g.expand() << endl;
82 // After .eval(), g should be zero:
83 if (!g.eval().is_zero()) {
84 clog << "e = (x + z*x); f = e*y; eval(f - e*y) erroneously returned "
88 // This actually worked already back in April 1999.
89 // But we are *very* paranoic!
90 if (!g.expand().eval().is_zero()) {
91 clog << "e = (x + z*x); f = e*y; eval(expand(f - e*y)) erroneously returned "
92 << g.expand().eval() << endl;
99 // The third bug was introduced on May 18th 1999, discovered on May 19 and
100 // fixed that same day. It worked when x was substituted by 1 but not with
102 static unsigned paranoia_check3(void)
105 symbol x("x"), y("y");
111 if (!f.is_equal(y)) {
112 clog << "e = x*y - y; f = e.subs(x == 2) erroneously returned "
116 if (!f.eval().is_equal(y)) {
117 clog << "e = x*y - y; eval(e.subs(x == 2)) erroneously returned "
121 if (!f.expand().is_equal(y)) {
122 clog << "e = x*y - y; expand(e.subs(x == 2)) erroneously returned "
123 << f.expand() << endl;
130 // The fourth bug was also discovered on May 19th 1999 and fixed immediately:
131 static unsigned paranoia_check4(void)
137 e = pow(x, 2) + x + 1;
138 f = pow(x, 2) + x + 1;
142 clog << "e = pow(x,2) + x + 1; f = pow(x,2) + x + 1; g = e-f; g erroneously returned "
147 clog << "e = pow(x,2) + x + 1; f = pow(x,2) + x + 1; g = e-f; g.eval() erroneously returned "
155 // The fifth oops was discovered on May 20th 1999 and fixed a day later:
156 static unsigned paranoia_check5(void)
159 symbol x("x"), y("y");
163 f = pow(x, 2) * pow(y, 2) + 2*x*y + 1;
165 if (!(e-f).expand().is_zero()) {
166 clog << "e = pow(x*y+1,2); f = pow(x,2)*pow(y,2) + 2*x*y + 1; (e-f).expand() erroneously returned "
167 << (e-f).expand() << endl;
174 // This one was discovered on Jun 1st 1999 and fixed the same day:
175 static unsigned paranoia_check6(void)
184 if (!f.is_equal(pow(x, 5))) {
185 clog << "e = pow(x, -5); f = e.denom(); f was " << f << " (should be x^5)" << endl;
191 // This one was introduced on June 1st 1999 by some aggressive manual
192 // optimization. Discovered and fixed on June 2nd.
193 static unsigned paranoia_check7(void)
196 symbol x("x"), y("y");
199 ex f = expand(pow(e, 2) - (e*y*(x + 1)));
202 clog << "e=y+y*x+2; f=expand(pow(e,2)-(e*y*(x+1))) has "
203 << f.nops() << " arguments instead of 3 ( f=="
204 << f << " )" << endl;
210 // This one was a result of the rewrite of mul::max_coefficient when we
211 // introduced the overall_coefficient field in expairseq objects on Oct 1st
212 // 1999. Fixed on Oct 4th.
213 static unsigned paranoia_check8(void)
223 if (!f.is_equal(e)) {
224 clog << "normal(-x/(x+1)) returns " << f << " instead of -x/(x+1)\n";
227 } catch (const exception &e) {
228 clog << "normal(-x/(x+1) throws " << e.what() << endl;
234 // This one was a result of a modification to frac_cancel() & Co. to avoid
235 // expanding the numerator and denominator when bringing them from Q[X] to
236 // Z[X]. multiply_lcm() forgot to multiply the x-linear term with the LCM of
237 // the coefficient's denominators (2 in this case). Introduced on Jan 25th
238 // 2000 and fixed on Jan 31th.
239 static unsigned paranoia_check9(void)
244 ex e = (exp(-x)-2*x*exp(-x)+pow(x,2)/2*exp(-x))/exp(-x);
247 if (!f.is_equal(1-2*x+pow(x,2)/2)) {
248 clog << "normal(" << e << ") returns " << f << " instead of 1-2*x+1/2*x^2\n";
254 // I have no idea when this broke. It has been working long ago, before 0.4.0
255 // and on Feb 13th 2000 I found out that things like 2^(3/2) throw an exception
256 // "power::eval(): pow(0,0) is undefined" instead of simplifying to 2*2^(1/2).
257 // It was fixed that same day.
258 static unsigned paranoia_check10(void)
268 if (!(r-2*sqrt(ex(2))).is_zero()) {
269 clog << "2^(3/2) erroneously returned " << r << " instead of 2*sqrt(2)" << endl;
272 } catch (const exception &e) {
273 clog << "2^(3/2) throws " << e.what() << endl;
279 // After the rewriting of basic::normal() & Co. to return {num, den} lists,
280 // add::normal() forgot to multiply the denominator of the overall_coeff of
281 // its expanded and normalized children with the denominator of the expanded
282 // child (did you get this? Well, never mind...). Fixed on Feb 21th 2000.
283 static unsigned paranoia_check11(void)
288 ex e = ((-5-2*x)-((2-5*x)/(-2+x))*(3+2*x))/(5-4*x);
290 ex d = (4+10*x+8*pow(x,2))/(x-2)/(5-4*x);
292 if (!(f - d).expand().is_zero()) {
293 clog << "normal(" << e << ") returns " << f << " instead of " << d << endl;
299 unsigned paranoia_check(void)
303 cout << "checking several ex-bugs just out of pure paranoia..." << flush;
304 clog << "---------several ex-bugs just out of pure paranoia:" << endl;
306 result += paranoia_check1();
307 result += paranoia_check2();
308 result += paranoia_check3();
309 result += paranoia_check4();
310 result += paranoia_check5();
311 result += paranoia_check6();
312 result += paranoia_check7();
313 result += paranoia_check8();
314 result += paranoia_check9();
315 result += paranoia_check10();
316 result += paranoia_check11();
320 clog << "(no output)" << endl;