Adding find_volume method for compatibility with the DAGMC interface

include/double_down/RTI.hpp

@@ -101,6 +101,11 @@ class RayTracingInterface {
   //! \brief Release all Embree scenes and device.
   void shutdown();
 
+  moab::ErrorCode
+  find_volume(const double xyz[3],
+              moab::EntityHandle& volume,
+              double* uvw=nullptr);
+
   //! \brief Check location \p xyz for containment in the specified \p volume.
   //! Performs a point containment query by firing a single ray and checking the dot product
   //! of the ray direction and the sense-adjusted normal of the triangle hit. Falls back onto

src/RTI.cpp

@@ -696,6 +696,22 @@ RayTracingInterface::point_in_volume_slow(moab::EntityHandle volume,
   return MB_SUCCESS;
 }
 
+moab::ErrorCode
+RayTracingInterface::find_volume(const double xyz[3],
+                                 moab::EntityHandle& volume,
+                                 double* uvw) {
+  int result = 0;
+  for (int i = 0; i < GTT->num_entities(3); i++) {
+    moab::EntityHandle vol = GTT->entity_by_index(3, i);
+    point_in_volume(vol, xyz, result, uvw);
+    if (result == 1) {
+      volume = vol;
+      break;
+    }
+  }
+  return moab::MB_SUCCESS;
+}
+
 moab::ErrorCode
 RayTracingInterface::point_in_volume(const moab::EntityHandle volume,
                                      const double xyz[3],