囚徒困境netlogo代码

下面是一个简单的囚徒困境模型的 NetLogo 代码：

globals [
  cooperate? ; 全局变量，表示是否合作
]

turtles-own [
  score ; 每个乌龟的得分
]

to setup
  clear-all
  reset-ticks
  set-default-shape turtles "person"
  create-turtles 2 [
    setxy random-xcor random-ycor
    set color ifelse-value (who = 0) [ red ] [ blue ]
    set heading random 360
    set score 0
  ]
  set cooperate? true
end

to go
  ask turtles [
    if cooperate? [
      set score score + 2
    ] else [
      set score score + 3
    ]
  ]
  ifelse (cooperate?) [
    ask turtle 0 [
      ifelse-value (random-float 1 < 0.5) [
        set cooperate? true
      ] [
        set cooperate? false
      ]
    ]
    ask turtle 1 [
      ifelse-value (random-float 1 < 0.5) [
        set cooperate? true
      ] [
        set cooperate? false
      ]
    ]
  ] [
    ask turtle 0 [
      ifelse-value (random-float 1 < 0.5) [
        set cooperate? true
      ] [
        set cooperate? false
      ]
    ]
    ask turtle 1 [
      ifelse-value (random-float 1 < 0.5) [
        set cooperate? false
      ] [
        set cooperate? true
      ]
    ]
  ]
  tick
end

这段代码创建了两只乌龟，分别表示两个囚徒。每个乌龟都有一个得分，初始化为0。在每个周期（tick）中，每个乌龟都会根据上一轮合作与否得分，然后根据当前的合作策略更新合作状态。随机选择一个乌龟先做出合作或背叛的决定，然后另一个乌龟根据自己的合作策略做出相应的决定。最终，两只乌龟的得分会根据他们的决策而变化。