Netlogo:agentset of patches to single agent

我有一个海龟（携带者）的名单，我正试图在我的围棋方法中缩小范围

这是我的节目：

globals [
metal-sheets
cut-sheets
standard-skeleton
finished-standard-skeleton
prestige-skeleton
finished-prestige-skeleton
]

breed[carriers carrier]

turtles-own [
on-job?
]

patches-own [
processing-time
  machine-type ;;cutter, standard-welder, prestige-welder, riveter
  status ;;import, export, pending
]

to setup
  clear-all
  set-default-shape carriers "circle"
  create-carriers number-of-carriers ;;number-of-carriers is a slider
  [set color grey
  set on-job? false
  setxy random-xcor random-ycor]
  setup-patches
  reset-ticks
end

to setup-patches
  ask patches [
    if pxcor = 1 and pycor = 1 [set machine-type "cutter"]
    if pxcor = 1 and pycor = 5 [set machine-type "standard-welder"]
    if pxcor = 5 and pycor = 1 [set machine-type "prestige-welder"]
    if pxcor = 5 and pycor = 5 [set machine-type "riveter"]

    if machine-type = "cutter" 
    [set pcolor red
    set status "import"]
    if machine-type = "standard-welder" 
    [set pcolor green
    set status "import"]
    if machine-type = "prestige-welder" 
    [set pcolor blue
    set status "import"]
    if machine-type = "riveter" 
    [set pcolor yellow
    set status "import"]
  ]
end

to Go

  let cutter patches  with [machine-type = "cutter"]
    let standard-welder patches with [machine-type = "standard-welder"]
    let prestige-welder patches with [machine-type = "prestige-welder"]
    let riveter patches with [machine-type = "riveter"]

  let free-carriers carriers with [on-job? = false]
  let closest-carrier min-one-of free-carriers [distance cutter] ;;Distance expects agent, got agentset

  ask closest-carrier [
    set color green
  ]
end

我在线路上遇到一个错误，

让最近的承运商在一个免费承运商[distance cutter]

中最小化，说distance需要一个代理，但得到了一个代理集，尽管集合中只有一个代理

完整的错误消息是：

DISTANCE预期输入为代理，但得到了代理集（代理集，1个补丁）。

---

如何将修补程序缩小到一个修补程序？

代理集中只有一个代理并不重要，它仍然是一个代理集。在前面放置一个中的一个，它从代理集中选择一个代理，从而改变代码解释代码的方式