Ultimatum Game - survival with offer level equal to level of rejection in agents

;; no age
;; children starts with wealth = 50

globals [ same-cycle
          different-cycle
          same-cycle-rejected
          different-cycle-rejected
          same-cycle-rejected%
          different-cycle-rejected%
          cycle-modifyer
        ]

breed [offer%=rejection%s offer%=rejection%]
breed [offer%!=rejection%s offer%!=rejection%]

turtles-own [ wealth
              offer%
              rejection%
              linked?
            ]

to setup
  ca
  create-offer%=rejection%s 500
      [ setxy random-xcor random-ycor
        set color green
        set wealth 50   ;; start off with 50. Each tick will minus 50 adjusted by carrying capacity. When wealth reaches 0, turtle dies
        set offer% random 100
        set rejection% offer%
        set cycle-modifyer 200 ;; allow the model to run 200 cycles, when offer%, rejection% and cycle-rejected% all stabilised.
        set linked? FALSE
      ]
  create-offer%!=rejection%s 500
      [ setxy random-xcor random-ycor
        set color red
        set wealth 50   ;; start off with 50. Each tick will minus 50 adjusted by carrying capacity. When wealth reaches 0, turtle dies
        set offer% random 100
        set rejection% random 100
        set cycle-modifyer 200 ;; allow the model to run 200 cycles, when offer%, rejection% and cycle-rejected% all stabilised.
        set linked? FALSE
      ]
  set same-cycle 0
  set different-cycle 0
  set same-cycle-rejected 0
  set different-cycle-rejected 0
  set same-cycle-rejected 0
  set different-cycle-rejected% 0
  set different-cycle-rejected% 0

  reset-ticks
end 

to go
  link-turtles
  ask turtles [if linked?  [calculate-wealth]] ;; if the initiator's offer is higher than the receiver's rejection threshold
  ask turtles [ set linked? false ]
  clear-links
  ;; each tick, with each pair of agent/turtle, total amount of 100 units are added to the "world", or average of 50 to each,
  ;; in order to simulate evolutionary process, where less successful strategies are weeded out by the "death" or removal of thos
  ;; caarying out those strategy, certain amount of "wealth" has to be removed from each agent/turtle, and since with
  ;; each round, on average 50 is added to each agent/turtle, the base unit 50 is taken off. This is adjusted by the ratio of
  ;; population vs the carrying-capacity of the "world" or the society. When additional "wealth"is added to the system in the form
  ;; of GDP-PC, it is distributed randomly from 0 to the amount as indicated in the slider minus 1 by the command, random GDP-PC.
  ;; For this reason, the amount deducted from each agent/turtle is GDP-PC / 2.
  ask turtles [ set wealth wealth - (50  * count turtles / carrying-capacity)
                reproduce
              ]
  ask turtles [ if wealth <= 0 [die]]
;  if ticks != 0 and ticks mod cycle-modifyer = 0 [ set cycle-modifyer random 500 + 1  ;; this sets the number of ticks before there will be a change in carrying-capacity
;                                   set carrying-capacity ((random 4 + 1 ) * 1000 )    ;; this sets how much the carrying-capacity is changed randomly in thousands
;                                 ]

;  if ticks > 200 [set carrying-capacity ticks] ;; to see effect of gradually increasing the carrying-capacity instead of having big jumps
  if count offer%=rejection%s = 0 [stop]
  if ticks >= 5000 [stop]
  tick
end 

to link-turtles
  ask turtles [if (not linked?) and any? other turtles with [linked? = false]
                    [ create-link-with one-of other turtles with [linked? != true ]
                      set linked? true
                      ask link-neighbors [set linked? true ]

                    ]
  ]
end 

to calculate-wealth
  ifelse breed = offer%!=rejection%s [set different-cycle different-cycle + 1]
                                     [set same-cycle same-cycle + 1]

  let t-offer% offer%
  let t-rejection% rejection%
  let t-wealth wealth
  let l-offer% 0
  let l-rejection% 0
  let l-wealth 0
  ask link-neighbors [ set l-offer% offer%
                       set l-rejection% rejection%
                       set l-wealth wealth]
  ;;print l-offer%
  ;;print [offer%] of link-neighbors
  ;;print l-rejection%
  ;;print [rejection%] of link-neighbors
  ;;print l-wealth
  ;;print [wealth] of link-neighbors
  ifelse t-offer% > l-rejection% [ set wealth wealth + ( 100 - offer%)
                               ask link-neighbors [ set wealth wealth + t-offer% ]
                                ]
                                 [ifelse breed = offer%!=rejection%s [set different-cycle-rejected different-cycle-rejected + 1]
                                                                        [set same-cycle-rejected same-cycle-rejected + 1]]
  if different-cycle != 0 [set different-cycle-rejected% different-cycle-rejected / different-cycle]
  if same-cycle != 0 [set same-cycle-rejected% same-cycle-rejected / same-cycle]
  set linked? false
  ask link-neighbors [set linked? false]
end 

to reproduce
  let wealth-factor (wealth / 100 - 1) * 10 ;; verified. At 100 wealth, there is a 50% probability of reproduction.
                                            ;; 100 is used because each tick the total amount invoved is 100
  let q 1 / (1 + exp (- wealth-factor) )   ;; logistic function for probability of reproduction. Verified
  let p random-float 1
  if p <= q [hatch 1 [ set wealth 50 ;; offspring starts 50, same as all new turtles
                       ifelse breed = offer%=rejection%s [ let r  random 1
                                                          ifelse r = 0 [ set offer%  (offer% + random 100) / 2  ;; this sets offer%, followed by rejection%
                                                                         set rejection% offer%]
                                                                       [ set rejection% (rejection% + random 100) / 2 ;; this sets rejection%, followed by offer%
                                                                         set offer% rejection% ]]
                                                        [ set offer% (offer% + random 100) / 2
                                                          set rejection% (rejection% + random 100 ) / 2 ]
                      ]

                       setxy random-xcor random-ycor ] ;; move away from the parent
end