Set upper and lower interpolation bounds for MGXS data.

Author: nuclearkevin

src/mgxs.cpp

@@ -14,6 +14,7 @@
 #include "openmc/error.h"
 #include "openmc/math_functions.h"
 #include "openmc/mgxs_interface.h"
+#include "openmc/nuclide.h"
 #include "openmc/random_lcg.h"
 #include "openmc/settings.h"
 #include "openmc/string_utils.h"
@@ -85,6 +86,13 @@ void Mgxs::metadata_from_hdf5(hid_t xs_id, const vector<double>& temperature,
   delete[] dset_names;
   std::sort(temps_available.begin(), temps_available.end());
 
+  // Set the global upper and lower interpolation bounds to avoid errors involving
+  // C-API functions.
+  for (int i = 0; i < num_temps; ++i) {
+    data::temperature_min = std::min(data::temperature_min, temps_available[i]);
+    data::temperature_max = std::max(data::temperature_max, temps_available[i]);
+  }
+
   // If only one temperature is available, lets just use nearest temperature
   // interpolation
   if ((num_temps == 1) &&