NetLogo

Question

此代码与 NetLogo 沙堆模型的改编有关。当每个补丁中的 go grains 计数超过阈值（在本例中为 3）时，grains 将重新分配给周围的邻居。我正在尝试将一粒谷物重新分配给 4 个随机相邻的补丁。

代码 returns 一个运行时间错误，因为边缘的补丁不会有所有 8 个邻居，所以当询问 4 个随机邻居时它 returns 一个错误说明可以不向 3 等请求 4 个赎金代理

我正在尝试找到一段代码来解决这个问题。

****代码如下*****

to-report stabilize [animate?]
  let active-patches patches with [ n > threshold ]

  ;; The number iterations the avalanche has gone for. Use to calculate lifetimes.
  let iters 0

  ;; we want to count how many patches became overloaded at some point
  ;; during the avalanche, and also flash those patches. so as we go, we'll
  ;; keep adding more patches to to this initially empty set.
  let avalanche-patches no-patches

  while [ any? active-patches ] [
    let overloaded-patches active-patches with [ n > threshold ]
    if any? overloaded-patches [
      set iters iters + 1

    ]
    ask overloaded-patches [
      set base-color fired-color
      ;; subtract 'threshold' amount from this patch
      update-n -4
      if animate? [ recolor ]
      ;; edge patches have less than four neighbors, so some sand may fall off the edge
      ask n-of 4 neighbors [
        update-n 1
        if animate? [ recolor ]
      ]
    ]
    if animate? [ display ]
    ;; add the current round of overloaded patches to our record of the avalanche
    ;; the patch-set primitive combines agentsets, removing duplicates
    set avalanche-patches (patch-set avalanche-patches overloaded-patches)
    ;; find the set of patches which *might* be overloaded, so we will check
    ;; them the next time through the loop
    set active-patches patch-set [ neighbors ] of overloaded-patches
  ]
  report (list avalanche-patches iters)
end

Answer 1

与其询问 4 个邻居，不如询问 min list 4 count neighbors:

ask n-of (min list 4 count neighbors) neighbors [ 
  ... 
]

但是从模型的角度来看，table的边缘会有不同的重分布，所以这不是一个好主意。也许最好有一个包裹的世界，然后手动 "push" 关闭 table: select 4 个邻居的颗粒，并只调用具有接近 pxcor 和 pycor 的那些。剩下的就关了table.

如果世界被包裹起来（水平和垂直），我们总是可以 select 4 个邻居：

let selected-neighbors n-of 4 neighbors

在这 4 个邻居中，只有真正的邻居在 table

set selected-neighbors selected-neighbors with [ 
  (abs (pxcor - [ pxcor ]  of myself) < 2) 
  and
  (abs (pycor - [ pycor ]  of myself) < 2) 
  ] 

ask selected-neighbors [
 ....
 ]

NetLogo - 将沙堆模型中的沙粒分配给随机邻居

NetLogo - Distributing grains of sand in sandpile model to random neighbours