Merge pull request #190 from lincc-frameworks/error_logging

Add some basic logging for errors in math node

src/tdastro/math_nodes/basic_math_node.py

@@ -125,7 +125,13 @@ def __init__(self, expression, backend="numpy", node_label=None, **kwargs):
         # Create a function from the expression. Note the expression has
         # already been sanitized and validated via _prepare().
         def eval_func(**kwargs):
-            return eval(self.expression, globals(), kwargs)
+            try:
+                return eval(self.expression, globals(), kwargs)
+            except Exception as problem:
+                # Provide more detailed logging, including the expression and parameters
+                # used, when we encounter a math error like divide by zero.
+                new_message = f"Error during math operation '{self.expression}' with args={kwargs}"
+                raise type(problem)(new_message) from problem
 
         super().__init__(eval_func, node_label=node_label, **kwargs)
 

tests/tdastro/math_nodes/test_basic_math_node.py

@@ -63,6 +63,22 @@ def test_basic_math_node_fail():
         _ = BasicMathNode("x + y", x=1.0)
 
 
+@pytest.mark.filterwarnings("ignore::RuntimeWarning")
+def test_basic_math_node_error():
+    """Test that we augment the error with information about the expression and parameters."""
+    node = BasicMathNode("y / x", x=0.0, y=1.0)
+    try:
+        node.sample_parameters()
+    except ZeroDivisionError as err:
+        assert str(err) == "Error during math operation 'y / x' with args={'x': 0.0, 'y': 1.0}"
+
+    node = BasicMathNode("sqrt(x)", x=-10.0)
+    try:
+        node.sample_parameters()
+    except ValueError as err:
+        assert str(err) == "Error during math operation 'np.sqrt(x)' with args={'x': -10.0}"
+
+
 def test_basic_math_node_numpy():
     """Test that we can perform computations via a BasicMathNode."""
     node_a = SingleVariableNode("a", 10.0)