From c5a587a2e1974d73a6968ef996168b9f085af66e Mon Sep 17 00:00:00 2001
From: "Todd A. Oliver" <oliver@oden.utexas.edu>
Date: Wed, 10 Jul 2024 17:07:17 -0500
Subject: [PATCH] Fix GroupCommunicator issue in scalarGrad3D (#288)

---
 src/utils.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/utils.cpp b/src/utils.cpp
index e58921c2f..3d83de4c0 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -905,8 +905,9 @@ void scalarGrad3D(ParGridFunction &u, ParGridFunction &gu) {
   gcomm.Bcast(zones_per_vdof);
 
   // Accumulate for all vdofs.
-  gcomm.Reduce<double>(gu.GetData(), GroupCommunicator::Sum);
-  gcomm.Bcast<double>(gu.GetData());
+  GroupCommunicator &gcomm_g = gu.ParFESpace()->GroupComm();
+  gcomm_g.Reduce<double>(gu.GetData(), GroupCommunicator::Sum);
+  gcomm_g.Bcast<double>(gu.GetData());
 
   // Compute means.
   for (int dir = 0; dir < dim; dir++) {