221-ex1

221-ex1

  def observe(self, observation, gameState):
    """
    Updates beliefs based on the distance observation and Pacman's position.
    
    The noisyDistance is the estimated manhattan distance to the ghost you are tracking.
    
    The emissionModel below stores the probability of the noisyDistance for any true 
    distance you supply.  That is, it stores P(noisyDistance | TrueDistance).

    self.legalPositions is a list of the possible ghost positions (you
    should only consider positions that are in self.legalPositions).

    A correct implementation will handle the following special case:
      *  When a ghost is captured by Pacman, all beliefs should be updated so
         that the ghost appears in its prison cell, position self.getJailPosition()

         You can check if a ghost has been captured by Pacman by
         checking if it has a noisyDistance of None (a noisy distance
         of None will be returned if, and only if, the ghost is
         captured).
         
    """
    noisyDistance = observation
    emissionModel = busters.getObservationDistribution(noisyDistance)
    pacmanPosition = gameState.getPacmanPosition()
    
    #print "Noisy Distance", noisyDistance
    #print "Emission Model", emissionModel
    #print "Pacman position", pacmanPosition
    #print "Beliefs", self.beliefs
    "*** YOUR CODE HERE ***"
    # Replace this code with a correct observation update
    # Be sure to handle the jail.
    allPossible = util.Counter()
    for p in self.legalPositions:
      trueDistance = util.manhattanDistance(p, pacmanPosition)
      if trueDistance == noisyDistance:
      	allPossible[p] = 1
      else:
      	allPossible[p] = 0
    #print allPossible
    allPossible.normalize()
    
    
    for p in self.legalPositions:
    	self.beliefs[p] += allPossible[p]
    self.beliefs.normalize()
    print "Max likely", max(self.beliefs.iteritems(), key=operator.itemgetter(1))[0]