FAI-889: Allow non-string categorical feature domains (#118)

* expanded feature domain flexibility

* removed vestigial debugging print

Author: RobGeada

src/trustyai/model/domain.py

@@ -3,17 +3,18 @@
 from typing import Optional, Tuple, List, Union
 
 from jpype import _jclass
+
 from org.kie.trustyai.explainability.model.domain import (
     FeatureDomain,
     NumericalFeatureDomain,
     CategoricalFeatureDomain,
+    CategoricalNumericalFeatureDomain,
+    ObjectFeatureDomain,
     EmptyFeatureDomain,
 )
 
 
-def feature_domain(
-    values: Optional[Union[Tuple, List[str]]]
-) -> Optional[FeatureDomain]:
+def feature_domain(values: Optional[Union[Tuple, List]]) -> Optional[FeatureDomain]:
     r"""Create a Java :class:`FeatureDomain`. This represents the valid range of values for a
     particular feature, which is useful when constraining a counterfactual explanation to ensure it
     only recovers valid inputs. For example, if we had a feature that described a person's age, we
@@ -22,13 +23,18 @@ def feature_domain(
 
     Parameters
     ----------
-    values : Optional[Union[Tuple, List[str]]]
+    values : Optional[Union[Tuple, List]]
         The valid values of the feature. If `values` takes the form of:
 
         * **A tuple of floats or integers:** The feature domain will be a continuous range from
           ``values[0]`` to ``values[1]``.
-        * **A list of strings:** The feature domain will be categorical, where `values` contains
-          all possible valid feature values.
+        * **A list of floats or integers:**: The feature domain will be a *numeric* categorical,
+        where `values` contains all possible valid feature values.
+        * **A list of strings:** The feature domain will be a *string* categorical, where `values`
+         contains all possible valid feature values.
+        * **A list of objects:** The feature domain will be an *object* categorical, where `values`
+         contains all possible valid feature values. These may present an issue if the objects
+         are not natively Java serializable.
 
         Otherwise, the feature domain will be taken as `Empty`, which will mean it will be held
         fixed during the counterfactual explanation.
@@ -43,12 +49,29 @@ def feature_domain(
     if not values:
         domain = EmptyFeatureDomain.create()
     else:
-        if isinstance(values[0], (float, int)):
-            domain = NumericalFeatureDomain.create(values[0], values[1])
-        elif isinstance(values[0], str):
-            domain = CategoricalFeatureDomain.create(
-                _jclass.JClass("java.util.Arrays").asList(values)
+        if isinstance(values, tuple):
+            assert isinstance(values[0], (float, int)) and isinstance(
+                values[1], (float, int)
+            )
+            assert len(values) == 2, (
+                "Tuples passed as domain values must only contain"
+                " two values that define the (minimum, maximum) of the domain"
             )
+            domain = NumericalFeatureDomain.create(values[0], values[1])
+
+        elif isinstance(values, list):
+            java_array = _jclass.JClass("java.util.Arrays").asList(values)
+            if isinstance(values[0], bool) and isinstance(values[1], bool):
+                domain = ObjectFeatureDomain.create(java_array)
+            elif isinstance(values[0], (float, int)) and isinstance(
+                values[1], (float, int)
+            ):
+                domain = CategoricalNumericalFeatureDomain.create(java_array)
+            elif isinstance(values[0], str):
+                domain = CategoricalFeatureDomain.create(java_array)
+            else:
+                domain = ObjectFeatureDomain.create(java_array)
+
         else:
             domain = EmptyFeatureDomain.create()
     return domain

tests/general/test_conversions.py

@@ -43,6 +43,37 @@ def test_numeric_domain_tuple():
     assert jdomain.getUpperBound() == 1000.0
 
 
+def test_categorical_numeric_domain_list():
+    """Test create numeric domain from list"""
+    domain = [0, 1000]
+    jdomain = feature_domain(domain)
+    assert jdomain.getCategories().size() == 2
+    assert jdomain.getCategories().containsAll(domain)
+
+    domain = [0.0, 1000.0]
+    jdomain = feature_domain(domain)
+    assert jdomain.getCategories().size() == 2
+    assert jdomain.getCategories().containsAll(domain)
+
+
+def test_categorical_object_domain_list():
+    """Test create object domain from list"""
+    domain = [True, False]
+    jdomain = feature_domain(domain)
+    assert str(jdomain.getClass().getSimpleName()) == "ObjectFeatureDomain"
+    assert jdomain.getCategories().size() == 2
+    assert jdomain.getCategories().containsAll(domain)
+
+
+def test_categorical_object_domain_list_2():
+    """Test create object domain from list"""
+    domain = [b"test", b"test2"]
+    jdomain = feature_domain(domain)
+    assert str(jdomain.getClass().getSimpleName()) == "ObjectFeatureDomain"
+    assert jdomain.getCategories().size() == 2
+    assert jdomain.getCategories().containsAll(domain)
+
+
 def test_empty_domain():
     """Test empty domain"""
     domain = feature_domain(None)
@@ -51,7 +82,7 @@ def test_empty_domain():
 
 def test_categorical_domain_tuple():
     """Test create categorical domain from tuple and list"""
-    domain = ("foo", "bar", "baz")
+    domain = ["foo", "bar", "baz"]
     jdomain = feature_domain(domain)
     assert jdomain.getCategories().size() == 3
     assert jdomain.getCategories().containsAll(list(domain))
@@ -61,7 +92,6 @@ def test_categorical_domain_tuple():
     assert jdomain.getCategories().size() == 3
     assert jdomain.getCategories().containsAll(domain)
 
-
 def test_feature_function():
     """Test helper method to create features"""
     f1 = feature(name="f-1", value=1.0, dtype="number")