Update default importance values to 1.0 in Importance class and tests

montepy/data_inputs/importance.py

@@ -95,7 +95,7 @@ def _generate_default_cell_tree(self, particle=None):
             particles.particles = self._problem.mode.particles
         classifier.particles = particles
         list_node = syntax_node.ListNode("imp data")
-        list_node.append(self._generate_default_node(float, 0.0))
+        list_node.append(self._generate_default_node(float, 1.0))
         tree = syntax_node.SyntaxNode(
             "Importance",
             {
@@ -163,7 +163,7 @@ def __getitem__(self, particle):
             val = self._particle_importances[particle]["data"][0]
             return val.value
         except KeyError:
-            return 0.0
+            return 1.0
 
     def __setitem__(self, particle, value):
         if not isinstance(particle, Particle):

pyproject.toml

@@ -15,7 +15,8 @@ authors = [
 	{name = "Brenna Carbno", email="[email protected]"},
 	{name = "Benjaminas Marcinkevicius", email="[email protected]"},
 	{name = "Paul Ferney", email="[email protected]"},
-	{name = "Digvijay Yeware", email="[email protected]"}
+	{name = "Digvijay Yeware", email="[email protected]"},
+	{name = "Harsh Dayal", email="[email protected]"}
 ]
 keywords = ["MCNP", "neutronics", "imcnp", "input file", "monte carlo", "radiation transport"]
 license = "MIT"

tests/test_importance.py

@@ -28,7 +28,7 @@ def create_cell_from_input(self, in_str, block=block_type.BlockType.CELL):
                     "neutron": 1.0,
                     "photon": 1.0,
                     "all": None,
-                    "alpha_particle": 0.0,
+                    "alpha_particle": 1.0,
                     "in_cell_block": True,
                 },
                 None,
@@ -40,7 +40,7 @@ def create_cell_from_input(self, in_str, block=block_type.BlockType.CELL):
             ),
             (
                 "1 0 -1",
-                {"neutron": 0.0},
+                {"neutron": 1.0},
                 None,
             ),  # default neutron importance when nothing is set
             # Error cases
@@ -267,9 +267,9 @@ def test_importance_deleter(self, cell_with_importance):
         """
         cell = cell_with_importance
         del cell.importance.neutron
-        assert cell.importance.neutron == pytest.approx(0.0)
+        assert cell.importance.neutron == pytest.approx(1.0)
         del cell.importance[Particle.PHOTON]
-        assert cell.importance.photon == pytest.approx(0.0)
+        assert cell.importance.photon == pytest.approx(1.0)
         with pytest.raises(TypeError):
             del cell.importance[""]
 
@@ -312,3 +312,8 @@ def test_default_importance_not_implemented(self):
         prob.print_in_data_block["imp"] = True
         with pytest.raises(NotImplementedError):
             prob.write_problem(io.StringIO())
+
+    def test_default_cell_importance(self):
+        """Test that new cells have default importance of 1.0 (Issue #735)"""
+        cell = montepy.Cell()
+        assert cell.importance.neutron == 1.0