From 3f601c90d29ed66f8b3a3729bacbe8feb444aad4 Mon Sep 17 00:00:00 2001
From: Hans Schoenemann <hannes@mathematik.uni-kl.de>
Date: Thu, 22 Aug 2024 09:44:03 +0200
Subject: [PATCH] also check for equal orderings in map_ideal (#821)

---
 src/map/alghom.jl | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/map/alghom.jl b/src/map/alghom.jl
index e63213009..b572d55c7 100644
--- a/src/map/alghom.jl
+++ b/src/map/alghom.jl
@@ -39,7 +39,21 @@ function map_ideal(f::Map(SAlgHom), I::sideal)
                 f.ptr, f.codomain.ptr, libSingular.ndCopyMap())
    
    J = Ideal(f.codomain,ptr)
-   J.isGB = I.isGB
+   # compare the orderings of f.domain.ptr and f.codomain.ptr
+   domain_ord=Cint[]
+   libSingular.rOrdering_helper(domain_ord, f.domain.ptr)
+   codomain_ord=Cint[]
+   libSingular.rOrdering_helper(codomain_ord, f.codomain.ptr)
+   equal_ordering=true
+   for i in 1:size(domain_ord,1)
+     if domain_ord[i] != codomain_ord[i]
+       equal_ordering=false
+       break
+     end
+   end
+   if equal_ordering
+     J.isGB = I.isGB
+   end
    return J
 end