refactor: replace attrs with __init__ method in FiniteStateMachine

src/komm/_finite_state_machine/FiniteStateMachine.py

@@ -4,7 +4,6 @@
 
 import numpy as np
 import numpy.typing as npt
-from attrs import field, frozen
 
 
 class MetricMemory(TypedDict):
@@ -16,7 +15,6 @@ class MetricMemory(TypedDict):
 MetricFunction = Callable[[int, Z], float]
 
 
-@frozen
 class FiniteStateMachine:
     r"""
     Finite-state machine (Mealy machine). It is defined by a *set of states* $\mathcal{S}$, an *input alphabet* $\mathcal{X}$, an *output alphabet* $\mathcal{Y}$, and a *transition function* $T : \mathcal{S} \times \mathcal{X} \to \mathcal{S} \times \mathcal{Y}$. Here, for simplicity, the set of states, the input alphabet, and the output alphabet are always taken as $\mathcal{S} = \\{ 0, 1, \ldots, |\mathcal{S}| - 1 \\}$, $\mathcal{X} = \\{ 0, 1, \ldots, |\mathcal{X}| - 1 \\}$, and $\mathcal{Y} = \\{ 0, 1, \ldots, |\mathcal{Y}| - 1 \\}$, respectively.
@@ -49,24 +47,22 @@ class FiniteStateMachine:
         >>> fsm = komm.FiniteStateMachine(next_states=[[0,1], [2,3], [0,1], [2,3]], outputs=[[0,3], [1,2], [3,0], [2,1]])
     """
 
-    next_states: npt.NDArray[np.integer] = field(
-        converter=np.asarray, repr=lambda x: x.tolist()
-    )
-    outputs: npt.NDArray[np.integer] = field(
-        converter=np.asarray, repr=lambda x: x.tolist()
-    )
-    _input_edges: npt.NDArray[np.integer] = field(init=False, repr=False)
-    _output_edges: npt.NDArray[np.integer] = field(init=False, repr=False)
-
-    def __attrs_post_init__(self) -> None:
-        input_edges = np.full((self.num_states, self.num_states), fill_value=-1)
-        output_edges = np.full((self.num_states, self.num_states), fill_value=-1)
+    def __init__(self, next_states: npt.ArrayLike, outputs: npt.ArrayLike):
+        self.next_states = np.asarray(next_states)
+        self.outputs = np.asarray(outputs)
+        self._input_edges = np.full((self.num_states, self.num_states), fill_value=-1)
+        self._output_edges = np.full((self.num_states, self.num_states), fill_value=-1)
         for state_from in range(self.num_states):
             for x, state_to in enumerate(self.next_states[state_from, :]):
-                input_edges[state_from, state_to] = x
-                output_edges[state_from, state_to] = self.outputs[state_from, x]
-        object.__setattr__(self, "_input_edges", input_edges)
-        object.__setattr__(self, "_output_edges", output_edges)
+                self._input_edges[state_from, state_to] = x
+                self._output_edges[state_from, state_to] = self.outputs[state_from, x]
+
+    def __repr__(self) -> str:
+        args = ", ".join([
+            f"next_states={self.next_states.tolist()}",
+            f"outputs={self.outputs.tolist()}",
+        ])
+        return f"{self.__class__.__name__}({args})"
 
     @cached_property
     def num_states(self) -> int: