fix bugs

Author: majosm

grudge/trace_pair.py

@@ -59,7 +59,7 @@
         ArrayContext,
         with_container_arithmetic,
         dataclass_array_container,
-        get_container_context_recursively,
+        get_container_context_recursively_opt,
         to_numpy,
         from_numpy)
 from arraycontext.container import ArrayOrContainerT
@@ -259,7 +259,7 @@ def bv_trace_pair(
                 DeprecationWarning, stacklevel=2)
         dd = dof_desc.as_dofdesc(dd)
     return bdry_trace_pair(
-        dcoll, dd, project(dcoll, "vol", dd, interior), exterior)
+        dcoll, dd, project(dcoll, dd.domain_tag.volume_tag, dd, interior), exterior)
 
 # }}}
 
@@ -471,7 +471,7 @@ def inter_volume_trace_pairs(dcoll: DiscretizationCollection,
         result[directional_vol_dd_pair] = [tpair]
 
     for directional_vol_dd_pair, tpairs in cross_rank_tpairs.items():
-        result.setdefault(directional_vol_dd_pair, []).append(tpairs)
+        result.setdefault(directional_vol_dd_pair, []).extend(tpairs)
 
     return result
 
@@ -839,7 +839,7 @@ def cross_rank_trace_pairs(
     assert len(remote_part_ids) == len(
         {dcoll._part_id_helper.get_mpi_rank(part_id) for part_id in remote_part_ids})
 
-    actx = get_container_context_recursively(ary)
+    actx = get_container_context_recursively_opt(ary)
 
     if actx is None:
         # NOTE: Assumes that the same number is passed on every rank
@@ -925,7 +925,7 @@ def cross_rank_inter_volume_trace_pairs(
 
     for vol_data_pair in pairwise_volume_data.values():
         for vol_data in vol_data_pair:
-            actx = get_container_context_recursively(vol_data)
+            actx = get_container_context_recursively_opt(vol_data)
             if actx is not None:
                 break
         if actx is not None: