将代理集转换为 NetLogo 中的列表

Question

我正在编写一些代码来为流感流行人群中的个体接种疫苗。疫苗有两种（代码中命名为HOV和HEV）； HOV 已经完成。我尝试/想要做的是将蓝海龟的代理集转换为一个列表，然后我可以一次迭代一只海龟。我需要这样做，因为 HEV 状况必须为每只蓝龟接种略有不同的疫苗（即每种疫苗中的流感毒株必须略有不同）。但是，NetLogo 突出显示“foreach [vax-turtles]”，并带有一条错误消息，上面写着“期望一个文字值”。

我的代码在下面，“如果疫苗=“HEV””这一段代码是我需要帮助的：

extensions [csv]
globals [strain_list_list epidemic-threshold cumulative-infections proportion-of-infection currently-infected peak-prevalence vax-strain]
turtles-own [infection-period infection-number tflu-strain immune-label ant-distance cross-immunity]
patches-own [fomite-age pflu-strain]

to setup
  clear-all
  setup-turtles
  set strain_list_list (list t-sorted-strain-list)
  print strain_list_list
  reset-ticks
end

to-report t-sorted-strain-list
  report map [i -> [tflu-strain] of i] sort turtles
end

to setup-turtles
  create-turtles 100
  ask turtles [setxy random-xcor random-ycor]
  ask turtles [set color white set infection-number 0 set immune-label -999999999999 set tflu-strain -999999999999]
  ask one-of turtles [set color red set infection-period 0 set infection-number 1 set immune-label 0 set tflu-strain 0]
  if vaccine = "HOV" [
    ifelse (one-of [1 2] = 1) [
      set vax-strain (random ((2 * drift-size) + 1))]
    [set vax-strain (-1 * random ((2 * drift-size) + 1))]
  ask n-of prop-vax turtles with [color = white] [set color blue set immune-label vax-strain]
  ]
  if vaccine = "HEV" [
    let vax-turtles (list turtles with [color = blue])
    ask n-of prop-vax turtles with [color = white] [set color blue] 
    foreach [vax-turtles] [
      ifelse (one-of [1 2] = 1) [
      set vax-strain (random ((2 * drift-size) + 1))]
    [set vax-strain (-1 * random ((2 * drift-size) + 1))]
      ]
    ]
  set epidemic-threshold "no"
  set cumulative-infections 0
  set peak-prevalence 0
end

to go
  if ticks = flu-season-length [stop]
  move-infecteds
  move-uninfecteds
  transmit
  mutate
  update-immunity
  track-infecteds
  set cumulative-infections (count turtles with [infection-period = 1] + cumulative-infections)
  set proportion-of-infection (100 - (count turtles with [immune-label = -999999999999]))
  set currently-infected (count turtles with [infection-period = 1])
  csv:to-file "strains_each_tick.csv" strain_list_list
  set strain_list_list lput t-sorted-strain-list strain_list_list
  tick
end

to move-uninfecteds ;; uninfected turtles move faster than infected ones
  ask turtles with [color = white or color = blue] [
    right random 360
    forward 5
  ]
end

to move-infecteds ;; infected turtles move slower than uninfected ones and always transmit infection to patches before they leave them
  ask turtles with [color = red] [
  if pcolor = black [
      set pcolor red
    set fomite-age 0
    set pflu-strain tflu-strain]
  right random 360
  forward 3
]
end

to transmit ;; uninfected turtles are infected by fomites (red patches) with some probability. immune-labelling currently first infection
  ask turtles with [color = white or color = blue and pcolor = red] [
    if immune-label != pflu-strain [
      set ant-distance (abs (immune-label - pflu-strain))
      set cross-immunity (natural-immunity * (1 - (ant-distance / antigenic-distance-limit)))
    if cross-immunity < 0 [set cross-immunity 0]
    if random 100 < (((100 - cross-immunity) / 100) * probability-of-infection)
      [set color red set infection-period 0 set infection-number infection-number + 1 set tflu-strain pflu-strain]
        ] 
  if immune-label = pflu-strain [ 
    if random 100 < (((100 - natural-immunity) / 100) * probability-of-infection)
      [set color red set infection-period 0 set infection-number infection-number + 1 set tflu-strain pflu-strain]
    ] 
]
end

to mutate ;; some probability of mutation (change in strain label) when an individual receives infection from a patch
  ifelse in-host [
    ask turtles with [color = red] [
     if random 100 < probability-of-mutation [
      ifelse (one-of [1 2] = 1) [
      set tflu-strain (tflu-strain + (random (drift-size + 1)))]
      [set tflu-strain (tflu-strain - (random (drift-size + 1)))]
     ]
    ]
   ]
  [ask turtles with [color = red and infection-period = 0] [
     if random 100 < probability-of-mutation [
      ifelse (one-of [1 2] = 1) [
      set tflu-strain (tflu-strain + (random (drift-size + 1)))]
      [set tflu-strain (tflu-strain - (random (drift-size + 1)))]
      ]
     ]
    ]
end

to update-immunity
  ask turtles with [color = red and infection-period = 0] [
    ifelse immune-labelling = "first-infection" [
  if immune-label = -999999999999 [
        set immune-label tflu-strain]]
  [set immune-label tflu-strain]
]
end

 to track-infecteds ;; turtles with given infection period should become uninfected
  ask turtles with [color = red] [
    set infection-period infection-period + 1
  if infection-period = age-infection-max [
    set color white set infection-period 0 set tflu-strain -999999999999
    ]
  ]
  ask patches with [pcolor = red] [
  set fomite-age fomite-age + 1
  if fomite-age > max-fomite-persistence [
  set pcolor black
    ]
  ]
end

任何建议将不胜感激！谢谢

Answer 1

问题出在线路上

let vax-turtles (list turtles with [color = blue])

list 原语创建一个列表，但不是turtles with [color = blue] 的列表。相反，它创建了一个参数列表，在这种情况下是一个单一的代理集。相反，您需要代理集 in 的代理列表。 of 记者是最简单的方法，因为of 总是返回一个列表。

let vax-turtles [self] of turtles with [color = blue]

或者，如果您希望对列表进行排序，您可以使用sort，它也总是返回一个列表。

let vax-turtles sort turtles with [color = blue]

至于您在下面的评论中描述的问题，您需要让每个 vax-turtle 设置自己的 vax-strain（我假设这是一个海龟自己的变量）。假设您使用的是 NetLogo 6.x，

if vaccine = "HEV" [
    let vax-turtles [self] of turtles with [color = blue]
    ask n-of prop-vax turtles with [color = white] [set color blue] 
    foreach [vax-turtles] [t ->
      ifelse (one-of [1 2] = 1) [
      ask t [set vax-strain (random ((2 * drift-size) + 1))]]
    [ask t [set vax-strain (-1 * random ((2 * drift-size) + 1))]]
      ]
    ]

但是，如果所有 vax-turtles 的漂移大小都相同，那么考虑到 random，JenB 的以下解决方案不太可能为任何两只海龟提供相同的 vax-strain 值，不是吗？

Answer 2

我认为

foreach sort-on [who] turtles with [color = blue]

足够了。

Answer 3

查看您的代码，我不明白为什么您需要进行迭代而不是询问，而且坚持询问要干净得多。所以，尝试替换：

if vaccine = "HEV" [
    let vax-turtles (list turtles with [color = blue])
    ask n-of prop-vax turtles with [color = white] [set color blue] 
    foreach [vax-turtles] [
      ifelse (one-of [1 2] = 1) [
      set vax-strain (random ((2 * drift-size) + 1))]
    [set vax-strain (-1 * random ((2 * drift-size) + 1))]
      ]
    ]

与

if vaccine = "HEV" [
    let vax-turtles turtles with [color = blue]
    ask n-of prop-vax turtles with [color = white] [set color blue] 
    ask [vax-turtles] [
      ifelse (one-of [1 2] = 1)
      [ set vax-strain (random ((2 * drift-size) + 1)) ]
      [ set vax-strain (-1 * random ((2 * drift-size) + 1)) ]
    ]
  ]

就此而言，我认为不同的值只是相同值的不同符号，所以你可以这样做：

if vaccine = "HEV" [
    let vax-turtles turtles with [color = blue]
    ask n-of prop-vax turtles with [color = white] [set color blue] 
    ask [vax-turtles] [
      set vax-strain one-of [-1 1] * (random ((2 * drift-size) + 1))
    ]
  ]

另外，我不确定您是否有意这样做，但您在创建 vax-turtles 代理集后将比例更改为蓝色。这意味着直到下一个tick 或下次运行代码时，新更改的海龟才会获得vax-strain。此外，您拥有的代码将为所有蓝色海龟分配一个新的vax-strain，即使它们在前面的步骤中被设为蓝色。如果您真的希望 vax-strain 只分配一次并且海龟更改颜色以显示此内容，请尝试：

if vaccine = "HEV" [
    ask n-of prop-vax turtles with [color = white]
    [ set color blue
      set vax-strain one-of [-1 1] * (random ((2 * drift-size) + 1))
      type "drift-size is " type drift-size type " and vax-strain is " print vax-strain ;; new line here for diagnostics
    ]
  ]

更新：ask 给每个代理一个新的随机数。您可以通过运行完整的模型来看到这一点：

turtles-own [testnum]

to setup
  clear-all
  create-turtles 10
  [ set testnum random 5 ]
  print [testnum] of turtles
end