From: Marc Fehling <mafehling.git@gmail.com>
Date: Wed, 5 Apr 2023 22:31:49 +0000 (-0600)
Subject: Fix interface mismatch in ScratchData in hp mode.
X-Git-Tag: v9.5.0-rc1~321^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F15105%2Fhead;p=dealii.git

Fix interface mismatch in ScratchData in hp mode.
---

diff --git a/source/meshworker/scratch_data.cc b/source/meshworker/scratch_data.cc
index fedca84bc4..8bb1d6b512 100644
--- a/source/meshworker/scratch_data.cc
+++ b/source/meshworker/scratch_data.cc
@@ -317,9 +317,15 @@ namespace MeshWorker
         // then we defer to the dominance of one FE over another. This should
         // ensure that the optimal integration order and mapping order are
         // selected for this situation.
-        const unsigned int dominated_fe_index =
-          fe_collection->find_dominated_fe(
-            {cell->active_fe_index(), neighbor_cell->active_fe_index()});
+        unsigned int dominated_fe_index = fe_collection->find_dominated_fe(
+          {cell->active_fe_index(), neighbor_cell->active_fe_index()});
+
+        // TODO: find_dominated_fe returns invalid_fe_index when no dominated FE
+        // has been found. We want to pass this value to FEFaceValues, but it
+        // expects an invalid_unsigned_int in this case. We need to match the
+        // interfaces in the future.
+        if (dominated_fe_index == numbers::invalid_fe_index)
+          dominated_fe_index = numbers::invalid_unsigned_int;
 
         hp_fe_face_values->reinit(cell,
                                   face_no,