- basic *copy = duplicate();
- copy->setflag(status_flags::dynallocated);
- copy->clearflag(status_flags::hash_calculated | status_flags::expanded);
- for (size_t i=0; i<num; i++)
- copy->let_op(i) = f(copy->op(i));
- return *copy;
+ basic *copy = NULL;
+ for (size_t i=0; i<num; i++) {
+ const ex & o = op(i);
+ const ex & n = f(o);
+ if (!are_ex_trivially_equal(o, n)) {
+ if (copy == NULL)
+ copy = duplicate();
+ copy->let_op(i) = n;
+ }
+ }
+
+ if (copy) {
+ copy->setflag(status_flags::dynallocated);
+ copy->clearflag(status_flags::hash_calculated | status_flags::expanded);
+ return *copy;
+ } else
+ return *this;
+}
+
+/** Check whether this is a polynomial in the given variables. */
+bool basic::is_polynomial(const ex & var) const
+{
+ return !has(var) || is_equal(ex_to<basic>(var));