return pseries(s, point, new_seq);
}
+// Differentiation is handled in function::derivative because of its special requirements
+
REGISTER_FUNCTION(Order, eval_func(Order_eval).
series_func(Order_series));
+//////////
+// Inert differentiation
+//////////
+
+static ex Diff_eval(const ex & f, const ex & x)
+{
+ return Diff(f, x).hold();
+}
+
+static ex Diff_deriv(const ex & f, const ex & x, unsigned deriv_param)
+{
+ GINAC_ASSERT(deriv_param == 0 || deriv_param == 1);
+ if (deriv_param == 1)
+ return Diff(Diff(f, x), x);
+ else
+ return _ex0();
+}
+
+REGISTER_FUNCTION(Diff, eval_func(Diff_eval).
+ derivative_func(Diff_deriv));
+
+//////////
+// Inert partial differentiation operator
+//////////
+
+static ex Derivative_eval(const ex & f, const ex & n)
+{
+ if (is_ex_exactly_of_type(n, numeric) && ex_to_numeric(n).is_nonneg_integer()) {
+ unsigned i = ex_to_numeric(n).to_int();
+ if (is_ex_exactly_of_type(f, function)) {
+ if (i < f.nops() && is_ex_exactly_of_type(f.op(i), symbol))
+ return Diff(f, f.op(i));
+ }
+ }
+ return Derivative(f, n).hold();
+}
+
+REGISTER_FUNCTION(Derivative, eval_func(Derivative_eval));
+
//////////
// Solve linear system
//////////