rsa.wppl

///first load and cleanup the data.
//TODO

var data = [2, 2, 2]

///next the RSA model, with a parameter for alternative weights.

var worldPrior = function() {
  var num_nice_people = randomInteger(4) //3 people.. 0-3 can be nice.
  return num_nice_people
}

var utterancePrior = function(altWeights) {
  var utterances = ["some of the people are nice",
                    "all of the people are nice",
                    "none of the people are nice"]
  var i = discrete(altWeights)
  return utterances[i]
}

var meaning = function(utt,world) {
  return utt=="some of the people are nice"? world>0 :
         utt=="all of the people are nice"? world==3 :
         utt=="none of the people are nice"? world==0 :
         true
}

var literalListener = cache(function(utterance) {
  Enumerate(function(){
    var world = worldPrior()
    var m = meaning(utterance, world)
    factor(m?0:-Infinity)
    return world
  })
})

var speaker = cache(function(world, altWeights) {
  Enumerate(function(){
    var utterance = utterancePrior(altWeights)
    var L = literalListener(utterance)
    factor(L.score([],world))
    return utterance
  })
})

var listener = function(altWeights, utterance) {
  display("run listener, altWeights: "+altWeights)
  Enumerate(function(){
    var world = worldPrior()
    var S = speaker(world, altWeights)
    factor(S.score([],utterance))
    return world
  })
}

var listenerScore = gpcache.cache(function(altWeights, utterance, world) {
                                  return listener(altWeights, utterance).score([],world)
                                  }, 1.0)


///now analyse the data against the RSA model. infer posterior on alternative weights.

var allWeight = MH(function(){
//   var altWeights = [1, uniform(0,1), 1]
   var altWeights = [1, uniformDraw([0.5, 1, 2]), 1]

   
   var utterance = "some of the people are nice"
   
   //TODO: response linking function?
   map(function(r){factor(listenerScore(altWeights, utterance, r))}, data)
   
   return altWeights[1]
   },
   100)

expectation(allWeight, function(x){return x})