From 7bd7be8f8693a4538d9c2f65878f7ffdddd8a8cd Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Fri, 7 Mar 2025 01:59:41 -0500
Subject: [PATCH] error out when trying unsupported pimd method with multiple
 processors per bead

---
 src/REPLICA/fix_pimd_langevin.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/REPLICA/fix_pimd_langevin.cpp b/src/REPLICA/fix_pimd_langevin.cpp
index 4e530bd97e..271725e238 100644
--- a/src/REPLICA/fix_pimd_langevin.cpp
+++ b/src/REPLICA/fix_pimd_langevin.cpp
@@ -523,7 +523,10 @@ void FixPIMDLangevin::setup(int vflag)
       nmpimd_transform(bufbeads, x, M_x2xp[universe->iworld]);
   } else if (method == PIMD) {
     inter_replica_comm(x);
-    spring_force();
+    if (cmode == SINGLE_PROC)
+      spring_force();
+    else if (cmode == MULTI_PROC)
+      error->universe_all(FLERR, "Method pimd only supports a single processor per bead");
   } else {
     error->universe_all(
         FLERR,