Newcomb's problem

breed [ players player ]
breed [predictors predictor ]

players-own [
             choice
             score
             linked?
            ]
predictors-own [ %correct
                 linked?
                ]

to setup
  ca
  reset-ticks
  create-players 1000 [
                      setxy random-xcor random-ycor
                      set score 0
                      ifelse random 2 = 1 [ set choice "AB" ]
                                          [ set choice "B"]
                      set shape  "person"
                      set color white
                      set linked? false
                     ]
  create-predictors 1000 [
                      setxy random-xcor random-ycor
                      set shape  "person"
                      set color red
                      set linked? false
                      set-%correct  ;; set each predictor's chance of getting the prediction correct
                     ]
end 

to go
  ask players [
               link-up
               choice-prediction-discovery
              ]
  ;; after one round, reset all links
  ask links [die]
  ask turtles [set linked? false]
  tick
  if ticks >= 20 [stop]
end 

to link-up
  if (not linked?)
                 [create-link-with one-of other predictors with [linked? != true]
                  set linked? true
                  ask link-neighbors [ set linked? true ]
                 ]
end 

to choice-prediction-discovery ;; to find out the choice and the prediction
  let %predictive-power item 0 [%correct] of link-neighbors
  let player-choice [choice] of self   ; the variable player-choice is set to the choice of the turtle that calls this function
  ifelse random-float 1 <= %predictive-power [ let predicted-choice choice   ;; if predictive power is correct
                                               if predicted-choice = "AB" and choice = "AB" [ set score score + 1000 ]
                                               if predicted-choice = "AB" and choice = "B" [ set score score + 0 ]
                                               if predicted-choice = "B" and choice = "AB" [ set score score + max-amount-in-B + 1000 ]
                                               if predicted-choice = "B" and choice = "B" [ set score score + max-amount-in-B ]
                                             ]
  ;; if predictive  power is wrong, then the predicted-choice would be the opposite of the choice
  ;; such that if the choice is "AB", the predicted-choice would be "B", and if the choice is "B", the predicted-choice would be "AB"
                                             [ let predicted-choice choice   ;; the calculation of the score will be flipped
                                               if predicted-choice = "B" and choice = "AB" [ set score score + 1000 ]
                                               if predicted-choice = "B" and choice = "B" [ set score score + 0 ]
                                               if predicted-choice = "AB" and choice = "AB" [ set score score + max-amount-in-B + 1000 ]
                                               if predicted-choice = "AB" and choice = "B" [ set score score + max-amount-in-B ]
                                             ]
end 

to set-%correct
  if average-accuracy = 0 [set %correct 0]
  if average-accuracy = 0.25 [set %correct random-float 0.5]
  if average-accuracy = 0.5 [set %correct random-float 1]
  if average-accuracy = 0.6 [set %correct random-float 0.4 + 0.4]
  if average-accuracy = 0.75 [set %correct random-float 0.5 + 0.5]
  if average-accuracy = 0.9 [set %correct random-float 0.2 + 0.8]
  if average-accuracy = 1 [set %correct 1]
end