如何在指定区域选取对应数量turtle修改颜色实现传染病模型初始感染设置

问题原因 #

现有代码中ask n-of initially_infected humans会从全局所有已创建的人类个体中随机选择，无法限定在对应区域：第一次执行时会从所有绿区人类中选对应数量的感染者，但第二次执行时会从绿区+蓝区所有人类中选，大概率选到已创建的绿区人类，既无法保证蓝区的初始感染数量，也做不到两区分别独立感染。

修正代码 #

to setup_agents
  create-humans green_population [
    move-to one-of patches with [pcolor = green and not any? humans-here]
    set shape "green person"
    set color yellow
    set size 1
    set green_antibodies 0
  ]
  ; 仅筛选绿区的人类设置初始感染
  ask n-of initially_infected humans with [ [pcolor] of patch-here = green ] [set color red]
  
  create-humans blue_population [
    move-to one-of patches with [pcolor = blue and not any? humans-here] 
    set shape "blue person"
    set color yellow
    set size 1
    set blue_antibodies 0  
  ] 
  ; 仅筛选蓝区的人类设置初始感染
  ask n-of initially_infected humans with [ [pcolor] of patch-here = blue ] [set color red]
end

优化方案（可选） #

如果需要提升执行效率，可在创建对应区域人群时直接存储临时变量引用，避免每次全局筛选：

to setup_agents
  let green-group nobody
  create-humans green_population [
    move-to one-of patches with [pcolor = green and not any? humans-here]
    set shape "green person"
    set color yellow
    set size 1
    set green_antibodies 0
    set green-group (turtle-set green-group self)
  ]
  ask n-of initially_infected green-group [set color red]
  
  let blue-group nobody
  create-humans blue_population [
    move-to one-of patches with [pcolor = blue and not any? humans-here] 
    set shape "blue person"
    set color yellow
    set size 1
    set blue_antibodies 0
    set blue-group (turtle-set blue-group self)
  ] 
  ask n-of initially_infected blue-group [set color red]
end

内容的提问来源于stack exchange，提问作者Aitezaz Ahsan