From baa92194ef488b8fe44bdb41f5936cae5a30a0d2 Mon Sep 17 00:00:00 2001
From: shriwise <pshriwise@gmail.com>
Date: Sat, 11 Aug 2018 08:30:12 -0500
Subject: [PATCH] Making Position/Direction structs more friendly for
 array-based signatures.

---
 include/openmc/position.h | 4 +---
 src/cell.cpp              | 8 ++------
 src/surface.cpp           | 6 ++----
 3 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/include/openmc/position.h b/include/openmc/position.h
index 56d01ba0a6..eff76dbca0 100644
--- a/include/openmc/position.h
+++ b/include/openmc/position.h
@@ -57,9 +57,7 @@ struct Position {
   }
 
   // Data members
-  double x = 0.;
-  double y = 0.;
-  double z = 0.;
+  union{ double xyz[3]; struct{ double x,y,z; }; };
 };
 
 // Binary operators
diff --git a/src/cell.cpp b/src/cell.cpp
index 1d71ff4da7..c544c5b3d9 100644
--- a/src/cell.cpp
+++ b/src/cell.cpp
@@ -599,12 +599,10 @@ CADCell::CADCell() : Cell{} {};
 
 std::pair<double, int32_t> CADCell::distance(Position p, Direction u, int32_t on_surface) const {
 
-  double xyz[3] = {p.x, p.y, p.z};
-  double uvw[3] = {u.x, u.y, u.z};
   moab::EntityHandle vol = dagmc_ptr->entity_by_id(3, id);
   moab::EntityHandle hit_surf;
   double dist;
-  dagmc_ptr->ray_fire(vol, xyz, uvw, hit_surf, dist);
+  dagmc_ptr->ray_fire(vol, p.xyz, u.xyz, hit_surf, dist);
 
   int surf_idx = dagmc_ptr->index_by_handle(hit_surf);
   
@@ -615,12 +613,10 @@ std::pair<double, int32_t> CADCell::distance(Position p, Direction u, int32_t on
   
 bool CADCell::contains(Position p, Direction u, int32_t on_surface) const {
 
-  double xyz[3] = {p.x, p.y, p.z};
-  double uvw[3] = {u.x, u.y, u.z};
   moab::EntityHandle vol = dagmc_ptr->entity_by_id(3, id);
 
   int result = 0;
-  dagmc_ptr->point_in_volume(vol, xyz, result, uvw);
+  dagmc_ptr->point_in_volume(vol, p.xyz, result, u.xyz);
   
   return bool(result);
 }
diff --git a/src/surface.cpp b/src/surface.cpp
index 5c05d9d403..18947a86bf 100644
--- a/src/surface.cpp
+++ b/src/surface.cpp
@@ -262,11 +262,9 @@ double CADSurface::distance(Position p, Direction u, bool coincident) const {
 
 Direction CADSurface::normal(Position p) const {
 
-  double xyz[3] = {p.x, p.y, p.z};
-  double uvw[3];
+  Direction u;
   moab::EntityHandle surf = dagmc_ptr->entity_by_id(2, id);
-  dagmc_ptr->get_angle(surf, xyz, uvw);
-  Direction u = {uvw};
+  dagmc_ptr->get_angle(surf, p.xyz, u.xyz);
   return u;
   
 }