Expose tally.writeable_ through openmc.lib

Add two functions to capi.h:
openmc_tally_set_writeable and openmc_tally_get_writeable
which are exposed to the Python API through the
openmc.lib.Tally.writeable property. These functions are very
similar to the set/get active counterparts as both act on a boolean
Tally attribute

A new unit test test_tally_writeable has been added that toggles
the writeable state of a tally. It is important to note that the
writeable state must be reset, otherwise tallies in subsequent
tests will be skewed. This is because the test_tally_writeable
function requires the capi_simulation_init fixture and the tallies
are shared by those functions that use the capi_run fixture

include/openmc/capi.h

@@ -110,6 +110,7 @@ extern "C" {
   int openmc_tally_get_nuclides(int32_t index, int** nuclides, int* n);
   int openmc_tally_get_scores(int32_t index, int** scores, int* n);
   int openmc_tally_get_type(int32_t index, int32_t* type);
+  int openmc_tally_get_writeable(int32_t index, bool* writeable);
   int openmc_tally_reset(int32_t index);
   int openmc_tally_results(int32_t index, double** ptr, size_t shape_[3]);
   int openmc_tally_set_active(int32_t index, bool active);
@@ -119,6 +120,7 @@ extern "C" {
   int openmc_tally_set_nuclides(int32_t index, int n, const char** nuclides);
   int openmc_tally_set_scores(int32_t index, int n, const char** scores);
   int openmc_tally_set_type(int32_t index, const char* type);
+  int openmc_tally_set_writeable(int32_t index, bool writeable);
   int openmc_zernike_filter_get_order(int32_t index, int* order);
   int openmc_zernike_filter_get_params(int32_t index, double* x, double* y, double* r);
   int openmc_zernike_filter_set_order(int32_t index, int order);

openmc/lib/tally.py

@@ -53,6 +53,9 @@ _dll.openmc_tally_get_scores.errcheck = _error_handler
 _dll.openmc_tally_get_type.argtypes = [c_int32, POINTER(c_int32)]
 _dll.openmc_tally_get_type.restype = c_int
 _dll.openmc_tally_get_type.errcheck = _error_handler
+_dll.openmc_tally_get_writeable.argtypes = [c_int32, POINTER(c_bool)]
+_dll.openmc_tally_get_writeable.restype = c_int
+_dll.openmc_tally_get_writeable.errcheck = _error_handler
 _dll.openmc_tally_reset.argtypes = [c_int32]
 _dll.openmc_tally_reset.restype = c_int
 _dll.openmc_tally_reset.errcheck = _error_handler
@@ -81,6 +84,9 @@ _dll.openmc_tally_set_scores.errcheck = _error_handler
 _dll.openmc_tally_set_type.argtypes = [c_int32, c_char_p]
 _dll.openmc_tally_set_type.restype = c_int
 _dll.openmc_tally_set_type.errcheck = _error_handler
+_dll.openmc_tally_set_writeable.argtypes = [c_int32, c_bool]
+_dll.openmc_tally_set_writeable.restype = c_int
+_dll.openmc_tally_set_writeable.errcheck = _error_handler
 _dll.tallies_size.restype = c_size_t
 
 
@@ -344,6 +350,16 @@ class Tally(_FortranObjectWithID):
 
         return std_dev
 
+    @property
+    def writeable(self):
+        writeable = c_bool()
+        _dll.openmc_tally_get_writeable(self._index, writeable)
+        return writeable.value
+
+    @writeable.setter
+    def writeable(self, writeable):
+        _dll.openmc_tally_set_writeable(self._index, writeable)
+
     def reset(self):
         """Reset results and num_realizations of tally"""
         _dll.openmc_tally_reset(self._index)

src/tallies/tally.cpp

@@ -1220,6 +1220,30 @@ openmc_tally_set_active(int32_t index, bool active)
   return 0;
 }
 
+extern "C" int
+openmc_tally_get_writeable(int32_t index, bool* writeable)
+{
+  if (index < 0 || index >= model::tallies.size()) {
+    set_errmsg("Index in tallies array is out of bounds.");
+    return OPENMC_E_OUT_OF_BOUNDS;
+  }
+  *writeable = model::tallies[index]->writeable_;
+
+  return 0;
+}
+
+extern "C" int
+openmc_tally_set_writeable(int32_t index, bool writeable)
+{
+  if (index < 0 || index >= model::tallies.size()) {
+    set_errmsg("Index in tallies array is out of bounds.");
+    return OPENMC_E_OUT_OF_BOUNDS;
+  }
+  model::tallies[index]->writeable_ = writeable;
+
+  return 0;
+}
+
 extern "C" int
 openmc_tally_get_scores(int32_t index, int** scores, int* n)
 {

tests/unit_tests/test_lib.py

@@ -256,9 +256,18 @@ def test_tally_activate(capi_simulation_init):
     assert t.active
 
 
+def test_tally_writeable(capi_simulation_init):
+    t = openmc.lib.tallies[1]
+    assert t.writeable
+    t.writeable = False
+    assert not t.writeable
+    # Revert tally to writeable state for capi_run fixtures
+    t.writeable = True
+
+
 def test_tally_results(capi_run):
     t = openmc.lib.tallies[1]
-    assert t.num_realizations == 10  # t was made active in test_tally
+    assert t.num_realizations == 10  # t was made active in test_tally_active
     assert np.all(t.mean >= 0)
     nonzero = (t.mean > 0.0)
     assert np.all(t.std_dev[nonzero] >= 0)