From 314edc655977f45e98b33f0625aba84ecb976079 Mon Sep 17 00:00:00 2001
From: Lukas Dreyer <lukas.dreyer@dlr.de>
Date: Tue, 21 Oct 2025 12:14:24 +0200
Subject: [PATCH 1/2] improve ancestor_id

---
 .../t8_standalone_implementation.hxx             | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/t8_schemes/t8_standalone/t8_standalone_implementation.hxx b/src/t8_schemes/t8_standalone/t8_standalone_implementation.hxx
index e82be32df7..b9da579edd 100644
--- a/src/t8_schemes/t8_standalone/t8_standalone_implementation.hxx
+++ b/src/t8_schemes/t8_standalone/t8_standalone_implementation.hxx
@@ -649,10 +649,22 @@ struct t8_standalone_scheme
 
     const t8_standalone_element<TEclass> *el = (const t8_standalone_element<TEclass> *) elem;
     t8_standalone_element<TEclass> ancestor;
+    const int length = element_get_len (level);
     T8_ASSERT (0 <= el->level && el->level <= T8_ELEMENT_MAXLEVEL[TEclass]);
 
-    element_get_ancestor (el, level, &ancestor);
-    return element_get_child_id ((const t8_element_t *) &ancestor);
+    int cube_id = 0;
+    for (int idim = 0; idim < T8_ELEMENT_DIM[TEclass]; idim++) {
+      cube_id |= (el->coords[idim] & length) ? (1 << idim) : 0;
+    }
+    int child_id;
+    if constexpr (T8_ELEMENT_NUM_EQUATIONS[TEclass]) {
+      u_int8_t type = element_compute_type_at_level (el, level);
+      child_id = t8_element_type_cubeid_to_Iloc<TEclass>[type][cube_id];
+    }
+    else {
+      child_id = cube_id;
+    }
+    return child_id;
   }
 
   /** Query whether a given set of elements is a family or not.

From bb8e4e411d8d1be7aee3b8fb67bc9f85926f027a Mon Sep 17 00:00:00 2001
From: "Dreyer, Lukas" <Lukas.Dreyer@dlr.de>
Date: Wed, 22 Oct 2025 13:46:11 +0200
Subject: [PATCH 2/2] remove unneeded variable

---
 src/t8_schemes/t8_standalone/t8_standalone_implementation.hxx | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/t8_schemes/t8_standalone/t8_standalone_implementation.hxx b/src/t8_schemes/t8_standalone/t8_standalone_implementation.hxx
index b9da579edd..af81a60b4a 100644
--- a/src/t8_schemes/t8_standalone/t8_standalone_implementation.hxx
+++ b/src/t8_schemes/t8_standalone/t8_standalone_implementation.hxx
@@ -648,7 +648,6 @@ struct t8_standalone_scheme
     T8_ASSERT (0 <= level && level <= T8_ELEMENT_MAXLEVEL[TEclass]);
 
     const t8_standalone_element<TEclass> *el = (const t8_standalone_element<TEclass> *) elem;
-    t8_standalone_element<TEclass> ancestor;
     const int length = element_get_len (level);
     T8_ASSERT (0 <= el->level && el->level <= T8_ELEMENT_MAXLEVEL[TEclass]);