From f857bce031d147d7d60e9dc327b53b2e5f6dc27a Mon Sep 17 00:00:00 2001 From: "Vladimir V. Kisil" Date: Mon, 14 Oct 2019 15:51:08 +0100 Subject: [PATCH] Power law for exponent. If it safe to evaluate (e^t)^s = e^(ts) at least in two cases: a) t and s are reals, the respective formula can be found in any analysis textbook. b) if s is an integer, then the ambiguity of t up to the term 2*Pi*k does not cause a different value. Signed-off-by: Vladimir V. Kisil --- ginac/inifcns_trans.cpp | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/ginac/inifcns_trans.cpp b/ginac/inifcns_trans.cpp index 232db8c5..9ce96e24 100644 --- a/ginac/inifcns_trans.cpp +++ b/ginac/inifcns_trans.cpp @@ -128,6 +128,14 @@ static ex exp_conjugate(const ex & x) return exp(x.conjugate()); } +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). expand_func(exp_expand). @@ -135,6 +143,7 @@ REGISTER_FUNCTION(exp, eval_func(exp_eval). real_part_func(exp_real_part). imag_part_func(exp_imag_part). conjugate_func(exp_conjugate). + power_func(exp_power). latex_name("\\exp")); ////////// -- 2.20.1