问在Netlogo中写一个概率函数，使得代理的某个值越大，则代理被选中的概率越大，怎么写代码？

breed [residences residence]
breed [scenic-spots scenic-spot]
breed [tourists tourist]

globals[
  ids
]

tourists-own [
  num-tourists
  myhome
  speed
  satisfaction
  state
  moving-time
  play-time
  waiting-time
  selected-spot
  visited-spots
  dist
  preference
]

scenic-spots-own[
  id
  capacity-1  ;观光娱乐
  capacity-2  ;餐饮住宿
  count-1
  count-2
  vacancy-1
  vacancy-2 
  value
]

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;; Setup procedures ;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

to setup
  ca
  setup-residences         ;市中心住宅区
  setup-scenic-spots       ;郊区游憩点
  setup-tourists           ;城镇居民
  if write-file? = true [prepare-file-output]
  reset-ticks
end

to-report within-circle? [x y cx cy radius]
  let d sqrt ((x - cx) ^ 2 + (y - cy) ^ 2)
  report d <= radius
end

to setup-scenic-spots  ; 创建景点
  set ids []
  let current-id 1  ; 设置初始id为1
  while [length ids < 10] [
    let new-x random-xcor
    let new-y random-ycor
    if not within-circle? new-x new-y 0 0 10 [
      create-scenic-spots 1 [
        set id current-id
        set shape "tree"
        set color green
        set size 3
        setxy new-x new-y
        set label id
        set capacity-1 100 + random 901 
        set capacity-2 100 + random 401
        set count-1 0
        set count-2 0
        set value 1 + random 9
        set vacancy-2 capacity-2
        set ids lput id ids  ; 将当前景点的id加入到ids列表中
      ]
      set current-id current-id + 1  ; 增加当前id
    ]
  ]
  print ids  ; 打印ids列表，用于验证结果
end


to setup-residences    ;创建住宅区
  create-residences 5 [
    ask residence 0 [setxy 0 0]
    ask residence 1 [setxy 4 -6]
    ask residence 2 [setxy 5 4]
    ask residence 3 [setxy -3 -4]
    ask residence 4 [setxy -3 5]
    set shape "house"
    set color red
    set size 4
  ]
end

to-report poisson-random-number [lambda] ;设置泊松函数
  let L exp(-1 * lambda)
  let k 0
  let p 1

  while [p > L] [
    set k k + 1
    set p p * random-float 1
  ]
  report k - 1
end

to setup-tourists
  let lambda 5  ; 泊松分布的参数λ
  let number-tourists poisson-random-number lambda  ; 生成符合泊松分布的随机数
  create-tourists number-tourists [
    set myhome one-of residences
    setxy [xcor] of myhome [ycor] of myhome
    set color blue
    set size 1
    set shape "person"
    set num-tourists number-tourists
    set satisfaction []
    set visited-spots []
]

end

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;; Go procedures ;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to go
 choose-spots
 service
 update-value
  tick
end

to choose-spots
  ask tourists [
    let total-preference 0
    set selected-spot nobody
    set state "initial"
    ask scenic-spots[
      let dist-to-tourist distance myself
      set dist dist-to-tourist
      let preference (value + (dist ^ -0.5))
      set total-preference total-preference + preference
    ]

    let rand-prob random-float total-preference ;随机概率rand-prob

    set selected-spot nobody
    let running-total 0

    ask scenic-spots [
      let preference (value + (dist ^ -0.5))
      if [selected-spot] of tourists = nobody and running-total + preference >= rand-prob [
        set selected-spot self
        print selected-spot
      ]
      set running-total running-total + preference
    ]
  ]
end