From: Pierangelo Masarati <pierangelo.masarati@polimi.it>
Date: Wed, 17 Jun 2020 17:52:49 +0000 (+0200)
Subject: Improve diff(abs(x)) for real x.
X-Git-Tag: release_1-7-10~5
X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=commitdiff_plain;h=fa1ffcfdc9da97a6fb7cc2c9c36fe1fc45c808a9

Improve diff(abs(x)) for real x.
---

diff --git a/ginac/inifcns.cpp b/ginac/inifcns.cpp
index d68afbb5..ec74a435 100644
--- a/ginac/inifcns.cpp
+++ b/ginac/inifcns.cpp
@@ -321,6 +321,8 @@ static ex abs_expand(const ex & arg, unsigned options)
 static ex abs_expl_derivative(const ex & arg, const symbol & s)
 {
 	ex diff_arg = arg.diff(s);
+	if (arg.info(info_flags::real))
+		return diff_arg*(2*step(arg) - 1);
 	return (diff_arg*arg.conjugate()+arg*diff_arg.conjugate())/2/abs(arg);
 }