From d92ed9f14baead60fdd6c1d823345cc3ddd1bc04 Mon Sep 17 00:00:00 2001
From: Cathy Yeh <cathy@driver.xyz>
Date: Wed, 17 Jan 2018 15:04:57 -0800
Subject: consolidate Node methods _init_factor_for_variable,
 _init_pi_received_msgs, into a single method _init_factors_for_variables

overrides of _init_factor_for_variable for BernoulliOr/AndNode not needed
---
 beliefs/models/belief_update_node_model.py | 79 ++++++++++--------------------
 1 file changed, 25 insertions(+), 54 deletions(-)

diff --git a/beliefs/models/belief_update_node_model.py b/beliefs/models/belief_update_node_model.py
index 1a9ab19..743bbcb 100644
--- a/beliefs/models/belief_update_node_model.py
+++ b/beliefs/models/belief_update_node_model.py
@@ -144,11 +144,14 @@ class Node:
         self.cardinality = cpd.cardinality[0]
         self.cpd = cpd
 
-        self.pi_agg = self._init_factor_for_variable()
-        self.lambda_agg = self._init_factor_for_variable()
+        self.pi_agg = self._init_factors_for_variables([self.label_id])[self.label_id]
+        self.lambda_agg = self._init_factors_for_variables([self.label_id])[self.label_id]
+
+        self.pi_received_msgs = self._init_factors_for_variables(self.parents)
+        self.lambda_received_msgs = \
+                {child: self._init_factors_for_variables([self.label_id])[self.label_id]
+                 for child in children}
 
-        self.pi_received_msgs = self._init_pi_received_msgs(self.parents)
-        self.lambda_received_msgs = {child: self._init_factor_for_variable() for child in children}
 
     @property
     def belief(self):
@@ -167,41 +170,33 @@ class Node:
     def _normalize(self, value):
         return value/value.sum()
 
-    def _init_factor_for_variable(self):
-        """
-        Returns
-            instance of a DiscreteFactor, where DiscreteFactor.values is an np.array of
-            ndim 1 and shape (self.cardinality,)
-        """
-        return DiscreteFactor(variables=[self.cpd.variable],
-                              cardinality=[self.cardinality],
-                              values=None,
-                              state_names=None)
-
-    def _init_pi_received_msgs(self, parents):
+    def _init_factors_for_variables(self, variables):
         """
         Args
-            parents: list,
-                list of strings, parent ids of the node
+            variables: list,
+                 list of ints/strings, e.g. the single node variable or list
+                 of parent ids of the node
         Returns
-            msgs: dict,
-                a dict with key, value pair as {parent_id: instance of a DiscreteFactor},
+            factors: dict,
+                where the dict has key, value pair as {variable_id: instance of a DiscreteFactor},
                 where DiscreteFactor.values is an np.array of ndim 1 and
-                shape (cardinality of parent_id,)
+                shape (cardinality of variable_id,)
         """
-        msgs = {}
-        for k in parents:
+        variables = list(variables)
+        factors = {}
+
+        for var in variables:
             if self.cpd.state_names is not None:
-                state_names = {k: self.cpd.state_names[k]}
+                state_names = {var: self.cpd.state_names[var]}
             else:
                 state_names = None
 
-            kth_cardinality = self.cpd.cardinality[self.cpd.variables.index(k)]
-            msgs[k] = DiscreteFactor(variables=[k],
-                                     cardinality=[kth_cardinality],
-                                     values=None,
-                                     state_names=state_names)
-        return msgs
+            cardinality = self.cpd.cardinality[self.cpd.variables.index(var)]
+            factors[var] = DiscreteFactor(variables=[var],
+                                          cardinality=[cardinality],
+                                          values=None,
+                                          state_names=state_names)
+        return factors
 
     def _return_msgs_received_for_msg_type(self, message_type):
         """
@@ -375,18 +370,6 @@ class BernoulliOrNode(Node):
     def __init__(self, label_id, children, parents):
         super().__init__(children=children, cpd=BernoulliOrCPD(label_id, parents))
 
-    def _init_factor_for_variable(self):
-        """
-        Returns
-            instance of a DiscreteFactor, where DiscreteFactor.values is an np.array of
-            ndim 1 and shape (self.cardinality,)
-        """
-        variable = self.cpd.variable
-        return DiscreteFactor(variables=[self.cpd.variable],
-                              cardinality=[self.cardinality],
-                              values=None,
-                              state_names={variable: self.cpd.state_names[variable]})
-
     def compute_pi_agg(self):
         """
         Compute and update pi_agg, the prior probability, given the current state
@@ -441,18 +424,6 @@ class BernoulliAndNode(Node):
     def __init__(self, label_id, children, parents):
         super().__init__(children=children, cpd=BernoulliAndCPD(label_id, parents))
 
-    def _init_factor_for_variable(self):
-        """
-        Returns
-            instance of a DiscreteFactor, where DiscreteFactor.values is an np.array of
-            ndim 1 and shape (self.cardinality,)
-        """
-        variable = self.cpd.variable
-        return DiscreteFactor(variables=[self.cpd.variable],
-                              cardinality=[self.cardinality],
-                              values=None,
-                              state_names={variable: self.cpd.state_names[variable]})
-
     def compute_pi_agg(self):
         """
         Compute and update pi_agg, the prior probability, given the current state
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