Add state indicator.

src/rlai/state_value/function_approximation/models/feature_extraction.py

@@ -32,24 +32,64 @@ def extract(
         """
 
 
-class StateDimensionIndicator(ABC):
+class StateIndicator(ABC):
     """
-    Abstract state-dimension indicator.
+    Abstract state indicator for one-hot feature encoding.
+    """
+
+    @abstractmethod
+    def __str__(
+            self
+    ) -> str:
+        """
+        Get string.
+
+        :return: String.
+        """
+
+    @abstractmethod
+    def get_range(
+            self
+    ) -> List[Any]:
+        """
+        Get the range (possible values) of the current indicator.
+
+        :return: Range of values.
+        """
+
+    @abstractmethod
+    def get_value(
+            self,
+            state_vector: np.ndarray
+    ) -> Any:
+        """
+        Get the value of the current indicator for a state.
+
+        :param state_vector: State vector.
+        :return: Value, which must be in the range returned by `get_range`.
+        """
+
+
+class StateLambdaIndicator(StateIndicator):
+    """
+    State indicator via lambda function.
     """
 
     def __init__(
             self,
-            dimension: Optional[int]
+            function: Callable[[np.ndarray], Any],
+            function_range: List[Any]
     ):
         """
         Initialize the indicator.
 
-        :param dimension: Dimension, or None for an indicator that is not based on a value of the state vector.
+        :param function: Function to apply to states.
+        :param function_range: Range of function.
         """
 
-        self.dimension = dimension
+        self.function = function
+        self.function_range = function_range
 
-    @abstractmethod
     def __str__(
             self
     ) -> str:
@@ -59,7 +99,8 @@ def __str__(
         :return: String.
         """
 
-    @abstractmethod
+        return '<function>'
+
     def get_range(
             self
     ) -> List[Any]:
@@ -69,22 +110,43 @@ def get_range(
         :return: Range of values.
         """
 
-    @abstractmethod
+        return self.function_range
+
     def get_value(
             self,
-            state: np.ndarray
+            state_vector: np.ndarray
     ) -> Any:
         """
         Get the value of the current indicator for a state.
 
-        :param state: State vector.
-        :return: Value.
+        :param state_vector: State vector.
+        :return: Value, which must be in the range returned by `get_range`.
         """
 
+        return self.function(state_vector)
+
+
+class StateDimensionIndicator(StateIndicator, ABC):
+    """
+    State-dimension indicator.
+    """
+
+    def __init__(
+            self,
+            dimension: int
+    ):
+        """
+        Initialize the indicator.
+
+        :param dimension: Dimension.
+        """
+
+        self.dimension = dimension
+
 
 class StateDimensionSegment(StateDimensionIndicator):
     """
-    Segment of a state dimension.
+    Indicates a segment of a state dimension.
     """
 
     @staticmethod
@@ -146,18 +208,17 @@ def get_range(
 
     def get_value(
             self,
-            state: np.ndarray
+            state_vector: np.ndarray
     ) -> Any:
         """
         Get the value of the current indicator for a state.
 
-        :param state: State vector.
+        :param state_vector: State vector.
         :return: Value.
         """
 
-        assert self.dimension is not None
+        dimension_value = float(state_vector[self.dimension])
 
-        dimension_value = float(state[self.dimension])
         above_low = self.low is None or dimension_value >= self.low
         below_high = self.high is None or dimension_value < self.high
 
@@ -171,14 +232,14 @@ class StateDimensionLambda(StateDimensionIndicator):
 
     def __init__(
             self,
-            dimension: Optional[int],
-            function: Callable[[Optional[float]], Any],
+            dimension: int,
+            function: Callable[[float], Any],
             function_range: List[Any]
     ):
         """
         Initialize the segment.
 
-        :param dimension: Dimension, or None for an indicator that is not based on a value of the state vector.
+        :param dimension: Dimension.
         :param function: Function to apply to values in the given dimension.
         :param function_range: Range of function.
         """
@@ -210,21 +271,16 @@ def get_range(self) -> List[Any]:
 
     def get_value(
             self,
-            state: np.ndarray
+            state_vector: np.ndarray
     ) -> Any:
         """
         Get the value of the current indicator for a state.
 
-        :param state: State vector.
+        :param state_vector: State vector.
         :return: Value.
         """
 
-        if self.dimension is None:
-            dimension_value = None
-        else:
-            dimension_value = float(state[self.dimension])
-
-        return self.function(dimension_value)
+        return self.function(float(state_vector[self.dimension]))
 
 
 class OneHotStateIndicatorFeatureInteracter:
@@ -263,7 +319,7 @@ def interact(
 
     def __init__(
             self,
-            indicators: List[StateDimensionIndicator]
+            indicators: List[StateIndicator]
     ):
         """
         Initialize the interacter.