add: exclusive support for np.ufunc in MathExpTrans

requirements.txt

@@ -1208,9 +1208,9 @@ scipy==1.10.0 ; python_version >= "3.8" and python_version < "3.11" \
     --hash=sha256:b901b423c91281a974f6cd1c36f5c6c523e665b5a6d5e80fcb2334e14670eefd \
     --hash=sha256:c8b3cbc636a87a89b770c6afc999baa6bcbb01691b5ccbbc1b1791c7c0a07540 \
     --hash=sha256:e096b062d2efdea57f972d232358cb068413dc54eec4f24158bcbb5cb8bddfd8
-setuptools==67.2.0 ; python_version >= "3.8" and python_version < "3.11" \
-    --hash=sha256:16ccf598aab3b506593c17378473978908a2734d7336755a8769b480906bec1c \
-    --hash=sha256:b440ee5f7e607bb8c9de15259dba2583dd41a38879a7abc1d43a71c59524da48
+setuptools==67.3.1 ; python_version >= "3.8" and python_version < "3.11" \
+    --hash=sha256:23c86b4e44432bfd8899384afc08872ec166a24f48a3f99f293b0a557e6a6b5d \
+    --hash=sha256:daec07fd848d80676694d6bf69c009d28910aeece68a38dbe88b7e1bb6dba12e
 simpful==2.9.0 ; python_version >= "3.8" and python_version < "3.11" \
     --hash=sha256:29b0c1fe1dab5dc9eb137cf8ac7fad5ca44443398bd3917f14a37df6dc7f55a4 \
     --hash=sha256:6d7e8077ac2b2499c3a1b86185cac52cc366d0a578428197b12575e451300855

src/sk_transformers/number_transformer.py

@@ -14,8 +14,9 @@ class MathExpressionTransformer(BaseTransformer):
     The operation can be a function from NumPy's mathematical functions or
     operator package.
 
-    **Warning!** Some functions/operators may not work as expected. Especially not all NumPy methods are supported. For example:
-    various NumPy methods return values which are not fitting the size of the source column.
+    **Warning!** Some functions/operators may not work as expected. Especially, functions that don't
+    belong in [`numpy.ufunc`](https://numpy.org/doc/stable/reference/ufuncs.html) are not supported.
+    NumPy functions with return values that don't fit the size of the source column are also not supported.
 
     Example:
     ```python
@@ -54,6 +55,10 @@ def __verify_operation(self, operation: str) -> Tuple[bool, Any]:
             if hasattr(np, operation[3:]):
                 op = getattr(np, operation[3:])
                 is_np_op = True
+                if not isinstance(op, np.ufunc):
+                    raise ValueError(
+                        f"The function `{operation}` is not a NumPy universal function. If you are using `np.sum` or `np.prod`, please use `np.add` or `np.multiply` instead."
+                    )
             else:
                 raise AttributeError(f"Operation {operation[3:]} not found in NumPy!")
 

tests/test_transformer/test_number_transformer.py

@@ -26,6 +26,17 @@ def test_math_expression_transformer_no_operation_method(X_numbers) -> None:
     )
 
 
+def test_math_expression_transformer_non_ufunc(X_numbers) -> None:
+    with pytest.raises(ValueError) as error:
+        MathExpressionTransformer(
+            [("small_numbers", "np.sum", "small_numbers", None)]
+        ).fit_transform(X_numbers)
+    assert (
+        "The function `np.sum` is not a NumPy universal function. If you are using `np.sum` or `np.prod`, please use `np.add` or `np.multiply` instead."
+        == str(error.value)
+    )
+
+
 def test_math_expression_transformer_in_pipeline(X_numbers) -> None:
     pipeline = make_pipeline(
         MathExpressionTransformer(
@@ -40,7 +51,6 @@ def test_math_expression_transformer_in_pipeline(X_numbers) -> None:
                 ),
                 ("small_numbers", "np.divide", "small_numbers", None),
                 ("small_numbers", "numpy.sin", None, None),
-                ("small_numbers", "np.sum", 1, None),
                 ("big_numbers", "neg", None, None),
             ]
         )
@@ -71,7 +81,6 @@ def test_math_expression_transformer_in_pipeline(X_numbers) -> None:
 
     assert pipeline.steps[0][0] == "mathexpressiontransformer"
     assert np.array_equal(result["small_numbers_add_1"].to_numpy(), expected_add)
-    assert np.array_equal(result["small_numbers_sum_1"].to_numpy(), expected_add)
     assert np.array_equal(
         result["small_numbers_mul_small_numbers"].to_numpy(), expected_mul
     )