* functions. */
/*
- * GiNaC Copyright (C) 1999-2017 Johannes Gutenberg University Mainz, Germany
+ * GiNaC Copyright (C) 1999-2020 Johannes Gutenberg University Mainz, Germany
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
return exp(x.conjugate());
}
+static ex exp_power(const ex & x, const ex & a)
+{
+ /*
+ * The power law (e^x)^a=e^(x*a) is used in two cases:
+ * a) a is an integer and x may be complex;
+ * b) both x and a are reals.
+ * Negative a is excluded to keep automatic simplifications like exp(x)/exp(x)=1.
+ */
+ if (a.info(info_flags::nonnegative)
+ && (a.info(info_flags::integer) || (x.info(info_flags::real) && a.info(info_flags::real))))
+ return exp(x*a);
+ else if (a.info(info_flags::negative)
+ && (a.info(info_flags::integer) || (x.info(info_flags::real) && a.info(info_flags::real))))
+ return power(exp(-x*a), _ex_1).hold();
+
+ return power(exp(x), a).hold();
+}
+
REGISTER_FUNCTION(exp, eval_func(exp_eval).
evalf_func(exp_evalf).
expand_func(exp_expand).
real_part_func(exp_real_part).
imag_part_func(exp_imag_part).
conjugate_func(exp_conjugate).
+ power_func(exp_power).
latex_name("\\exp"));
//////////
// maybe substitution of rel into arg fails because of a pole
try {
arg_pt = arg.subs(rel, subs_options::no_pattern);
- } catch (pole_error) {
+ } catch (pole_error &) {
must_expand_arg = true;
}
// or we are at the branch point anyways