From dcb735feae4c3a6962a7824e03b0ce4496e3ffe7 Mon Sep 17 00:00:00 2001
From: Stefan Weinzierl <weinzierl@uni-mainz.de>
Date: Wed, 9 Jun 2021 14:10:23 +0200
Subject: [PATCH] Bug fix in the routine H_evalf (a minus sign should not be
 forgotten).

This bug was reported by Bin Zhou.
---
 ginac/inifcns_nstdsums.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/ginac/inifcns_nstdsums.cpp b/ginac/inifcns_nstdsums.cpp
index c6f5012a..51ba0641 100644
--- a/ginac/inifcns_nstdsums.cpp
+++ b/ginac/inifcns_nstdsums.cpp
@@ -3318,7 +3318,9 @@ static ex H_evalf(const ex& x1, const ex& x2)
 			// x -> 1-x
 			if (has_minus_one) {
 				map_trafo_H_convert_to_Li filter;
-				return filter(H(m, numeric(x)).hold()).evalf();
+                                // 09.06.2021: bug fix: don't forget a possible minus sign from the case realpart(x) < 0
+				res *= filter(H(m, numeric(x)).hold()).evalf();
+				return res;
 			}
 			map_trafo_H_1mx trafo;
 			res *= trafo(H(m, xtemp).hold());
-- 
2.44.0