tracking q5

tracking/inference.py

@@ -354,7 +354,11 @@ class DiscreteDistribution(dict):
         {}
         """
         "*** YOUR CODE HERE ***"
-        raiseNotDefined()
+        total_prob = self.total()
+        if total_prob == 0:
+            return
+        for key in self.keys():
+            self[key] /= total_prob
         "*** END YOUR CODE HERE ***"
 
     def sample(self):
@@ -379,7 +383,15 @@ class DiscreteDistribution(dict):
         0.0
         """
         "*** YOUR CODE HERE ***"
-        raiseNotDefined()
+        total_prob = self.total()
+        if total_prob == 0:
+            return None
+        rand_num = random.random() * total_prob
+        for key in self.keys():
+            rand_num -= self[key]
+            if rand_num <= 0:
+                return key
+        return key
         "*** END YOUR CODE HERE ***"
 
 
@@ -454,7 +466,19 @@ class InferenceModule:
         Return the probability P(noisyDistance | pacmanPosition, ghostPosition).
         """
         "*** YOUR CODE HERE ***"
-        raiseNotDefined()
+        if(jailPosition==ghostPosition):
+            if noisyDistance==None:
+                return 1
+            else:
+                return 0
+        if noisyDistance==None:
+            # the ghost is in the jail
+            if ghostPosition==jailPosition:
+                return 1
+            else:
+                return 0
+        true_distance=manhattanDistance(pacmanPosition,ghostPosition)
+        return busters.getObservationProbability(noisyDistance,true_distance)
         "*** END YOUR CODE HERE ***"
 
     def setGhostPosition(self, gameState, ghostPosition, index):