如何在NetLogo中循环？

Question

我有以下问题。我需要循环通过代码。但是，它不起作用。

问题的上下文化:我有3个文件(在.asc中)，表示涉及海龟3岁( 2岁、4岁和8岁)的数据。我希望如果用户将值1放在num-user中，它将只使用一个表示"2“的文件(L_2)进行模拟；如果用户将值2放在num-user中，他将对表示"2”"4“的文件(L_2和L_4)进行模拟，最后，如果用户将值3输入num-use，它将模拟表示"2”"4“"8”的文件(L_2、L_4和L_8)。问题是循环不工作，会产生各种错误。例如:扩展异常: ascii文件./L8.asc未找到或找不到列表2 4 8中的元素3，该元素仅为3或go运行了3次以上的模拟。

我无法将.ascii文件附加到这个问题中。但是，如果有人能够查看代码并识别错误，我将非常感激。我不能使用BehaviouSpace来解决这种情况，我需要在代码中使用这个循环。

提前感谢！

extensions [ gis ]

globals [ num turtle-ages num-ages files random-seeds  num-user repetitions ]

to setup
  ca
  
  set random-seeds 1
  random-seed random-seeds
  set num 0
  set turtle-ages [ "2" "4" "8" ]
  set num-ages item num turtle-ages
  setup-asc
  setup-turtles
  reset-ticks
end

to setup-2
  clear
  random-seed random-seeds
  set num-ages item num turtle-ages
  setup-asc
  setup-turtles
  reset-ticks
end

to setup-turtles
ask n-of 5 patches [ sprout 1 ]
end

to clear
  set files 0
  clear-ticks
  clear-turtles
end

to setup-asc
  let number1 num-ages
  set files gis:load-dataset ( word "./L_" number1 ".asc" ) ;; this loads a one raster file. There are 3 files in the folder with the names: (L_2.asc ; L_4.asc and L_8.asc
end

to go
  move
  tick
  let n count turtles
  if n = 0 or ticks = 10
  [
    set random-seeds random-seeds + 1
    set repetitions 1
    if random-seeds = repetitions + 1
    [
      set random-seeds 1

      set num num + 1
      
      ;; if the user puts the value 1 in num-user, it would only do the simulation with only one file (L_2) that would represent [ "2" ] 
      ;;; if the user puts the value 2 in num-user, he would do the simulation with the files (L_2 and L_4) that would represent [ "2" "4" ] 
      ;;;; and finally, if the user puts the value 3 in num-use, it would simulate the files (L_2 , L_4 and L_8) that would represent [ "2" "4" "8" ]
      set num-user 1 ;;
      if num = num-user [ stop ]
    ]
    setup-2
  ]
end

to move
  ask turtles [ 
    right random 360
    fd 1
    if ticks = 5 [ die ]
  ]
end

Answer 1

只要有可能，我建议把你的代码削减到一个MRE到a)，确保这里的用户可以运行你的代码(例如，没有你的文件，这是不可行的)和b)，看看用更简单的术语重新规划你的问题/目标是否有助于让事情正常运行--至少这才是对我有用的！

我认为，在这里，您可能会发现foreach作为一种循环所需模拟的方法很有用，而不是手动跟踪迭代次数。在本例中，假设num-user是接口上的一个数字输入小部件，下面的设置将确定要处理的年份：

globals [ ages-to-run ]
  
to base-setup
  ca
  ; Determine how many simulations to run, based on user input into
  ; 'num-user' numerical input widget on the interface
  ifelse num-user < 1 or num-user > 3 [
    print "Incorrect number of simulations indicated"
  ] [
    let possible-sims [ "2" "4" "8" ]
    set ages-to-run sublist possible-sims 0 num-user
  ]  
  reset-ticks
end

运行上述操作后，ages-to-run变量将包含["2"]、["2" "4"]或["2" "4" "8"]。接下来，您可以遍历所需的时间来运行您的模拟(在注释中有更多的细节)：

to run-simulations 
  if ages-to-run = 0 [
    print "Simulation setup not complete"
  ]
  
  foreach ages-to-run [
    ; This is the loop proper where each "age" is iterated.
    ; All of your simulation calls (manual variable resetting,
    ; etc) should all go within this loop.
    current-age ->
    print word "Running simulations for age: " current-age
    let file-to-load ( word "./L_" current-age ".asc" )
    print file-to-load
    clear-turtles
    ask n-of 5 patches [ 
      sprout 1 [ 
        pd 
        set color runresult current-age + 55
      ] 
    ]
    repeat 20 [
      ask turtles [
        rt random 60 - 30
        fd 1
      ]
      tick
    ]
    print ( word "Simulations complete for age: " current-age "\n" )  
  ]
end

在输入到3中的num-user中运行上面的代码将为每个年龄运行模拟(不同的颜色表示不同的运行)：

​

​

因此，为了正确地运行模拟，您的所有年龄代码都应该在上面指出的foreach循环内，并且要小心，就像您的问题一样，不要重置全局变量。