如何修复 NetLogo 6.0.4 中的 "Nothing named ? has been defined" 错误

Question

我下载了修改后的随机簇代码，用于使用 NetLogo 建模共享中的 Millington 版本的修改后的随机簇方法生成中性景观模型。当我单击 "generate-landscape" 按钮时，代码中的 "fill-landscape" 过程导致 "Nothing named ? has been defined" 错误。

当我创建附加的界面图像并尝试运行下面的相邻代码时。问题似乎与 "occurrences" 报告功能中的问号有关。 reduce 函数未按预期工作。有解决办法吗？看界面，然后代码如下：

  ifelse ( any? neighbours with [ cluster != nobody ] )  ;; check if there are any assigned patches in neighbourhood
  [

    let covers []

    ask neighbours with [ cluster != nobody ]
    [
      set covers fput cover covers    ;;ask neighbours to add their covers to the list
    ]

    let unique-covers remove-duplicates covers    ;;create a list of unique covers

    let max-cover-count -1                 ;the number of neighbours with the maximum cover
    let max-cover -1                       ;the maximum cover

    ifelse(length unique-covers > 1)
    [
      ;if there is more than one unique-cover
      foreach unique-covers                  ;for each of the unique covers
      [
        let occ occurrences ? covers          ;count how many neighbours had this cover

        ifelse(occ > max-cover-count)        ;if the count is greater than the current maximum count
        [ 
          set max-cover ?                    ;set this as the dominant cover
          set max-cover-count occ            ;update the current maximum count

;---------------

to-report occurrences [x the-list]
  report reduce
    [ifelse-value (?2 = x) [?1 + 1] [?1]] (fput 0 the-list)
end 
;---------------

该代码假定使用由 Saura 和 Martinez-Millan (2000) 开发的修改后的随机集群方法生成中性景观模型。但是，错误"Nothing named ? has been defined"错误的代码来自运行ning顺利。期待思想...

Answer 1

NetLogo 5.x 中的旧 ? 语法在 NetLogo 6 中被新的 -> 语法取代。参见 https://ccl.northwestern.edu/netlogo/docs/programming.html#anonymous-procedures

因此，例如，在 NetLogo 5 中，您可以这样写：

foreach [0 1 2 3] [
  print ?
]

在 NetLogo 6 中，你写：

foreach [0 1 2 3] [ x ->
  print x
]

Answer 2

Bryan 的答案（第一个过程）和 NetLogo 词典（第二个过程）的组合为您提供了以下内容。注释表示新的位。未测试。

ifelse ( any? neighbours with [ cluster != nobody ] )
[ let covers []
  ask neighbours with [ cluster != nobody ]
  [ set covers fput cover covers
  ]
  let unique-covers remove-duplicates covers
  let max-cover-count - 1  ; added a space around subtraction
  let max-cover - 1        ; more spacing
  ifelse(length unique-covers > 1)
  [ foreach unique-covers
    [ this-cover ->                  ; here's the new bit, calling ? 'this-cover'
      let occ occurrences this-cover covers ; passes to the occurrences procedure
      ifelse(occ > max-cover-count)
      [ set max-cover this-cover     ; using the name this-cover again
        set max-cover-count occ

对于出现的情况，您可以直接从 NetLogo 词典中获取程序 reduce 示例

to-report occurrences [#x #the-list]
  report reduce
    [ [occurrence-count next-item] -> ifelse-value (next-item = #x)
        [occurrence-count + 1] [occurrence-count] ] (fput 0 #the-list)
end

如何修复 NetLogo 6.0.4 中的 "Nothing named ? has been defined" 错误

How to fix "Nothing named ? has been defined" error in NetLogo 6.0.4

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