From 67aca58079d4c68cfd6f1d6e9e781232f74131f2 Mon Sep 17 00:00:00 2001
From: Patrick Shriwise <pshriwise@gmail.com>
Date: Thu, 12 Nov 2020 10:12:01 -0600
Subject: [PATCH] Adding ifdefs to fix builds without DAGMC.

---
 src/particle.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/particle.cpp b/src/particle.cpp
index 73cdb3dd6a..5c6d0d466a 100644
--- a/src/particle.cpp
+++ b/src/particle.cpp
@@ -286,7 +286,9 @@ Particle::event_collide()
   // Score flux derivative accumulators for differential tallies.
   if (!model::active_tallies.empty()) score_collision_derivative(*this);
 
+  #ifdef DAGMC
   history_.reset();
+  #endif
 }
 
 void
@@ -502,6 +504,10 @@ Particle::cross_reflective_bc(const Surface& surf, Direction new_u)
   coord(0).cell = cell_last(n_coord_last() - 1);
   surface() = -surface();
 
+  #ifdef DAGMC
+  if (surf->geom_type_ != GeometryType::DAGMC) history_.reset();
+  #endif
+
   // If a reflective surface is coincident with a lattice or universe
   // boundary, it is necessary to redetermine the particle's coordinates in
   // the lower universes.