From c37b5e50b1fa4f7c0dd159c1d37bba0b237758f4 Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Fri, 3 Jul 2020 22:35:53 -0400
Subject: [PATCH] flag error when trying to compute an average of an empty
 vector

---
 src/variable.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/variable.cpp b/src/variable.cpp
index efdc701c1a..e3733314af 100644
--- a/src/variable.cpp
+++ b/src/variable.cpp
@@ -4205,6 +4205,9 @@ int Variable::special_function(char *word, char *contents, Tree **tree,
       if (eval_in_progress[ivar])
         print_var_error(FLERR,"Variable has circular dependency",ivar);
 
+      if ((method == AVE) && (nvec == 0))
+        print_var_error(FLERR,"Cannot compute average of empty vector",ivar);
+
       double *vec;
       nvec = compute_vector(ivar,&vec);
       nstride = 1;