From e6eda4cbc78593d4cfc9e8001cdbc7f062a8d1c5 Mon Sep 17 00:00:00 2001
From: Sebastian Blauth <sebastian.blauth@itwm.fraunhofer.de>
Date: Fri, 8 Nov 2024 16:24:03 +0100
Subject: [PATCH 1/3] USe the ghost offset correctly for interpolating the
 levelset function to cells

---
 cashocs/_utils/interpolations.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/cashocs/_utils/interpolations.py b/cashocs/_utils/interpolations.py
index 1a5ea9bc..65e245af 100644
--- a/cashocs/_utils/interpolations.py
+++ b/cashocs/_utils/interpolations.py
@@ -132,10 +132,11 @@
 
     std::vector<unsigned int> cells = mesh->cells();
     int meshdim = mesh->geometry().dim();
+    auto ghost_offset = mesh->topology().ghost_offset(meshdim);
 
     if (meshdim == 2){
         int index = 0;
-        for (int i=0; i<cells.size(); i+=3){
+        for (int i=0; i<ghost_offset*3; i+=3){
             psi0 = vertex_values[cells[i]];
             psi1 = vertex_values[cells[i+1]];
             psi2 = vertex_values[cells[i+2]];
@@ -155,7 +156,7 @@
     }
     else if (meshdim == 3){
         int index = 0;
-        for (int i=0; i<cells.size(); i+=4){
+        for (int i=0; i<ghost_offset*4; i+=4){
             psi0 = vertex_values[cells[i]];
             psi1 = vertex_values[cells[i+1]];
             psi2 = vertex_values[cells[i+2]];

From 02dc61c769d6a65bcb4240d6f2a46fc42fb74ee8 Mon Sep 17 00:00:00 2001
From: Sebastian Blauth <sebastian.blauth@itwm.fraunhofer.de>
Date: Mon, 11 Nov 2024 14:39:49 +0100
Subject: [PATCH 2/3] Fix some small mpi related bugs

---
 cashocs/_utils/interpolations.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/cashocs/_utils/interpolations.py b/cashocs/_utils/interpolations.py
index 65e245af..9f79de0e 100644
--- a/cashocs/_utils/interpolations.py
+++ b/cashocs/_utils/interpolations.py
@@ -247,7 +247,8 @@ def interpolate_by_volume(
     )
     arr = fenics.assemble(form_td * test * dx)
     vol = fenics.assemble(test * dx)
-    node_function.vector()[:] = arr[:] / vol[:]
+    node_function.vector().set_local(arr[:] / vol[:])
+    node_function.vector().apply("")
 
 
 def interpolate_by_angle(
@@ -440,3 +441,4 @@ def interpolate_by_angle(
     values /= weights
     d2v = fenics.dof_to_vertex_map(cg1_space)
     node_function.vector()[:] = values[d2v]
+    node_function.vector().apply("")

From 902f37aed489f4beb66c34f9fb30a4edb2392170 Mon Sep 17 00:00:00 2001
From: Sebastian Blauth <sebastian.blauth@itwm.fraunhofer.de>
Date: Mon, 11 Nov 2024 14:47:40 +0100
Subject: [PATCH 3/3] Raise exception for angle weighted interpolation in
 parallel

---
 .../topology_optimization_algorithm.py                 | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/cashocs/_optimization/topology_optimization/topology_optimization_algorithm.py b/cashocs/_optimization/topology_optimization/topology_optimization_algorithm.py
index 68798a33..b48b8026 100755
--- a/cashocs/_optimization/topology_optimization/topology_optimization_algorithm.py
+++ b/cashocs/_optimization/topology_optimization/topology_optimization_algorithm.py
@@ -90,6 +90,16 @@ def __init__(
         self._cashocs_problem.db.parameter_db.problem_type = "topology"
 
         self.mesh = optimization_problem.mesh
+
+        mpi_comm = self.mesh.mpi_comm()
+        if self.interpolation_scheme == "angle" and mpi_comm.Get_size() > 1:
+            raise _exceptions.InputError(
+                "TopologyOptimizationProblem",
+                "TopologyOptimization.interpolation_scheme",
+                "The angle weighted interpolation option is not supported in parallel. "
+                "Please use interpolation_scheme = volume in your config file.",
+            )
+
         self.cg1_space = fenics.FunctionSpace(self.mesh, "CG", 1)
         self.dg0_space = optimization_problem.dg0_space
         self.topological_derivative_vertex: fenics.Function = fenics.Function(