fix edge case

Author: jonahm-LANL

spiner/databox.hpp

@@ -42,7 +42,7 @@
 namespace Spiner {
 
 enum class IndexType { Interpolated = 0, Named = 1, Indexed = 2 };
-enum class DataStatus { Empty, Unmanaged, AllocatedHost, AllocatedDevice };
+enum class DataStatus { Empty = 0, Unmanaged = 1, AllocatedHost = 2, AllocatedDevice = 3 };
 enum class AllocationTarget { Host, Device };
 
 template <typename T = Real, typename Grid_t = RegularGrid1D<T>,
@@ -302,6 +302,10 @@ class DataBox {
 
   DataBox<T, Grid_t, Concept>
   getOnDevice() const { // getOnDevice is always a deep copy
+    if (size == 0 || status_ == DataStatus::Empty) { // edge case for unallocated
+      DataBox<T, Grid_t, Concept> a;
+      return a;
+    }
     // create device memory (host memory if no device)
     T *device_data = (T *)PORTABLE_MALLOC(sizeBytes());
     // copy to device