- e = pow(x-1,4) - expand(pow(x-1,4)); // ...and after differentiating twice.
- try {
- ex f = sqrfree(e);
- if (!f.is_zero()) {
- clog << "sqrfree(" << e << ") returns " << f << " instead of 0\n";
+// Bug in power expansion
+unsigned exam_paranoia26()
+{
+ unsigned result = 0;
+ symbol x("x"), y("y"), a("a");
+ possymbol s("s"), t("t");
+ exmap pwrs =
+ { {pow((x+1)*(y-2)*(s-3)*(t+4), a), pow((x+1)*(y-2)*(s-3), a)*pow(t+4, a)},
+ {pow(2*(x+1)*(y-2)*(s-3)*(t+4), a), pow(2,a)*pow((x+1)*(y-2)*(s-3), a)*pow(t+4, a)},
+ {pow(-(x+1)*(y-2)*(s-3)*(t+4), a), pow(-(x+1)*(y-2)*(s-3), a)*pow(t+4, a)},
+ {pow(-2*(x+1)*(y-2)*(s-3)*(t+4), a), pow(2,a)*pow(-(x+1)*(y-2)*(s-3), a)*pow(t+4, a)} };
+
+ for (auto e : pwrs) {
+ if (! (e.first.expand()).is_equal(e.second) ) {
+ clog << "power expansion of " << e.first << " produces error.\n";