[GiNaC-devel] Powers of exponents

[Vladimir V. Kisil]

>>>>> On Fri, 02 Oct 2009 07:11:51 -0500, Stephen Montgomery-Smith <stephen at missouri.edu> said:
    SMS> I think it is wrong to include "x is an integer."  Even 1^i
    SMS> (which is exp(0)^i) is not well defined (it can be any of e^(2
    SMS> pi n) for all integers).

	Alright, here is the patch to stay on the safe side.

	Best wishes,
	Vladimir
-- 
Vladimir V. Kisil     email: kisilv at maths.leeds.ac.uk
--                      www: http://maths.leeds.ac.uk/~kisilv/
-------------- next part --------------
--- inifcns_trans.cpp	2009-02-17 13:39:22.000000000 +0000
+++ patches/inifcns_trans.cpp	2009-10-02 15:45:17.000000000 +0100
@@ -99,9 +99,18 @@
 	return exp(GiNaC::real_part(x))*sin(GiNaC::imag_part(x));
 }
 
+static ex exp_power(const ex & x, const ex & a)
+{
+	if (a.info(info_flags::integer) || (x.info(info_flags::real) && a.info(info_flags::real)))
+		return exp(x*a);
+
+	return power(exp(x), a).hold();
+}
+
 REGISTER_FUNCTION(exp, eval_func(exp_eval).
                        evalf_func(exp_evalf).
                        derivative_func(exp_deriv).
+                       power_func(exp_power).
                        real_part_func(exp_real_part).
                        imag_part_func(exp_imag_part).
                        latex_name("\\exp"));