From 1ac90815f3426d0b19775e497ca84bf3bfa80a4e Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Sun, 17 Sep 2017 23:58:10 -0400
Subject: [PATCH] fix external only needs to collect virial in case it is
 requested

---
 src/fix_external.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/fix_external.cpp b/src/fix_external.cpp
index ab942f874c..a3b697bb2b 100644
--- a/src/fix_external.cpp
+++ b/src/fix_external.cpp
@@ -197,6 +197,7 @@ void FixExternal::set_energy_global(double caller_energy)
 
 void FixExternal::set_virial_global(double *caller_virial)
 {
+  if (!evflag) return;
   if (!vflag_global) return;
 
   for (int i = 0; i < 6; i++)
@@ -224,6 +225,7 @@ void FixExternal::set_virial_peratom(double **caller_virial)
 {
   int i,j;
 
+  if (!evflag) return;
   if (!vflag_atom) return;
 
   int nlocal = atom->nlocal;