From dc99e204d3b0fb7d55b9eb90ce884c39ff4fab02 Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Wed, 26 Feb 2025 13:40:19 -0500
Subject: [PATCH] bugfix from Trung to avoid problems with read_dump when not
 all MPI ranks have atoms

---
 src/read_dump.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/read_dump.cpp b/src/read_dump.cpp
index 5972b369c8..59fe6c6767 100644
--- a/src/read_dump.cpp
+++ b/src/read_dump.cpp
@@ -710,12 +710,14 @@ void ReadDump::read_atoms()
         while (nsend < nread) {
           lo = MAX(ofirst,rfirst);
           hi = MIN(olast,rlast);
-          if (otherproc)    // send to otherproc or copy to self
-            MPI_Send(&buf[nsend][0],(hi-lo)*nfield,MPI_DOUBLE,
+          int numel = (hi-lo)*nfield;
+          if (otherproc && numel > 0) { // send to otherproc or copy to self
+            MPI_Send(&buf[nsend][0],numel,MPI_DOUBLE,
                      otherproc,0,clustercomm);
+          }
           else
             memcpy(&fields[rfirst][0],&buf[nsend][0],
-                   (hi-lo)*nfield*sizeof(double));
+                   numel*sizeof(double));
           nsend += hi-lo;
           if (hi == olast) {
             otherproc++;