如何：计算补丁集的地理中心？

Question

我在 NetLogo 中对领土选择进行建模，海龟选择一个领土中心（“开始补丁”），然后根据补丁的值从那里构建一个领土。海龟在获得新补丁后总是返回起始补丁，然后选择、移动到并获得下一个最有价值的补丁。选择领地后，乌龟知道它拥有哪些斑块，而斑块也知道它们的主人。

最终，一块领土的起点可能并不是真正的地理中心。海龟选择了它的领地后，我如何要求它评估领地、识别地理中心并计算起始块与领地真正中心的接近度？ （注：我不想强迫海龟将起始补丁保留在地理中心——它们可以自由选择它们想要的任何补丁。但如果没有一个区域，我可能会强制海龟重新选择一个领土。势均力敌的比赛——否则这些地区的效率不是很高。）

以下是领土起始斑块（黑色星星）不等于地理中心的示例。下面是一些示例代码。有什么建议吗？

patches-own [
    benefit   ;; ranges 0.1-1 and represents food available in the patch
    owner ]   ;; patches are owned once selected for a territory

turtles-own [
    start-patch     ;; the selected center of the territory
    sum-value       ;; sum of values of patches in my territory 
    territory-list  ;; list of patches I've selected
    territory       ;; agentset of patches I've selected
    established ]   ;; true/false, true when has settled in a final territory after assessing geographic center

globals [threshold = 25]

to setup
    ask patches [ set owner nobody ]
end

to go 
    ask turtles [
        pick-center
        build-territory]
    tick
end

to pick-center
  if start-patch = 0
  [move-to best-center  ;; (calculated by a reporter elsewhere as moving windows for a cluster of high-benefit patches)
   set start-patch patch-here
   set owner self
   set territory-list (list patch-here)
   set territory (patches with [owner = myself]) 
  ]

to build-territory
     ifelse sum-value < threshold 
     [ pick-patch ]  ;; keeps picking patches for territory until I've met my threshold
     [ assess-geographic-center]  ;; once met threshold, assess real center of patch-set
end 

to pick-patch
    let _destination highest-value  ;; (this is calculated by reporters elsewhere based on benefit / travel costs to a patch)
    face _destination forward 1   
      if patch-here = _destination
        [ claim-patch _destination ]

end

to claim-patch [_patch]
     ask _patch [set owner myself]
     set sum-value sum-value + (benefit / (distance start-patch))
     set territory-list lput patch-here territory-list
     set territory (patch-set territory _patch)
     move-to start-patch
end

to assess-geographic-center
     ;; Once the territory is built, the turtle should identify the actual 
     ;; geographic center of the patch-set it has selected...how to do this?
     ;; Once it knows the center, the turtle should compare the distance to the original start-patch.
     ;; If >10 patches away, it will move to that start-patch and start over with selecting a territory....
end

Answer 1

你能只得到所有补丁的平均 pxcor 和 pycor 吗？比如：

to setup

  ca
  reset-ticks
  let n 70

  ask one-of patches [
    set pcolor red
  ]

  while [ ( count patches with [pcolor = red ] ) < n ] [
    ask one-of patches with [ pcolor = red ] [
      ask one-of neighbors4 [set pcolor red ]

    ]
  ]

  let xmean mean [pxcor] of patches with [ pcolor = red ]
  print xmean
  let ymean mean [pycor] of patches with [ pcolor = red ]
  print ymean

  ask patch xmean ymean [ set pcolor blue
  ]

end

Answer 2

根据之前的答案，这是我的想法。这出现在我原始代码的最后一个过程中：

to assess-geographic-center
     let xmean mean [pxcor] of patches with [ owner = myself ]
     let ymean mean [pycor] of patches with [ owner = myself ]
     ask patch xmean ymean [ set pcolor black ]  ;; make the geographic center visible
     let geographic-center patch xmean ymean  
     let distance-away distance geographic-center  ;; the turtle is on its start-patch when assessing this distance
     ifelse distance-away <= 5   
        [ set established true ]  ;; turtle is happy if start-patch and geographic-center are approximately equal, territory "established"
        [ move-to geographic-center  ;; otherwise, turtle moves to geographic-center,
          reposition ]  ;; and follows a procedure "reposition" to makes this the new start-patch and repick the territory
end