NetLogo疏散模拟问题：乘客行为异常与Setup按钮报错排查

一、Setup按钮报错修复 #

报错原因 #

choose-exit过程中构建PP列表的语法错误：(patch-set [neighbors4] of lucky-exit with [accessible?])错误地将筛选逻辑嵌套在patch-set内部，导致NetLogo将单个patch识别为agentset输入，触发类型不匹配错误。

修复方法 #

将PP列表的构建改为直接对出口的4邻域patch集进行筛选，正确代码如下：

; 修正PP列表构建逻辑
let pp-list neighbors4 of lucky-exit with [accessible?]

二、乘客智能移动修复（解决徘徊、越界问题） #

问题根源 #

1. 每次go循环都会重新调用choose-exit，导致乘客频繁更换目标，方向反复变化出现徘徊；
2. move过程未判断patch-ahead是否存在（边界外情况），导致越界；
3. 到达LPP后未继续朝向出口，而是重新计算目标，导致停滞。

修复方法 #

1. 调整go逻辑，仅当乘客未到达目标区域时才重新计算目标：

to go
  type "----------------------------[GO.tick]\n"
  ask passengers [
    if panic? and not safe? [
      ; 仅未到达出口或其邻域时重新选择目标
      if not (patch-here = target-exit or member? patch-here neighbors4 of target-exit) [
        set target-exit choose-exit patch-here
      ]
      face target-exit
    ]
    move
  ]
  tick
end

2. 完善move过程，增加边界与可达性判断：

to move
  if panic? and not safe? [
    let next-patch patch-ahead 1
    ; 确保下一个patch存在、可达且无其他乘客
    if next-patch != nobody and [accessible?] of next-patch and not any? other passengers-here [
      move-to next-patch
      ; 到达出口标记为安全
      if member? patch-here exits-list [
        set safe? true
        set color green ; 用颜色直观标记安全状态
      ]
    ]
  ]
end

3. 调整choose-exit逻辑，让LPP作为临时目标，出口作为长期目标：

to-report choose-exit [current-position]
  ; ... 保留原有计算最近出口、权重选择出口的逻辑 ...

  ; 计算出口的PP集合（4邻域可达patch）
  let pp-list neighbors4 of lucky-exit with [accessible?]
  let M count pp-list
  ; PP为空时直接选择出口作为目标
  let lpp ifelse-value (M > 0) [one-of pp-list] [lucky-exit]
  
  face lpp
  set my-exits-list lput lucky-exit my-exits-list
  
  ; 返回出口作为长期目标，确保乘客最终朝向出口移动
  report lucky-exit
end

三、完善PP/LPP机制实现 #

核心实现逻辑 #

• PP定义：出口的4邻域中accessible? = true的patch，确保仅包含可达区域；
• LPP选择：使用one-of pp-list实现均等概率选择（每个PP被选中概率为1/M，M为PP数量）；
• 边界处理：当PP为空（如出口被阻挡）时，直接将出口设为目标，避免无有效移动方向。

修改后的choose-exit中PP/LPP相关代码：

; 计算出口的PP集合
let pp-list neighbors4 of lucky-exit with [accessible?]
let M count pp-list
; 处理PP为空的边界情况
let lpp ifelse-value (M > 0) [one-of pp-list] [lucky-exit]
; 朝向LPP移动
face lpp

完整修复后代码 #

breed [  passengers    passenger]
breed [  fire-spots  a-fire-spot]
breed [ smoke-spots a-smoke-spot]

globals [        exit1            ;;   pID
                 exit2            ;;   pID
                 exits-list       ;; [ pID ... ]
                 passenger_count  ;;   integer
                 exit-probabilities ;; [probability ...]
]

passengers-own [ in-seat?         ;; boolean
                 safe?            ;; boolean
                 dead?            ;; boolean
                 panic?           ;; boolean
                 current-heading  ;; turtleHDG
                 target-exit      ;;   pID
                 my-exits-list    ;; [ pID ... ]
                 item?            ;; boolean
]

patches-own [    accessible?      ;; boolean
                 fire?            ;; boolean
]

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; FUNZIONI SETUP ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to setup
   __clear-all-and-reset-ticks
   type "----------------------------[SETUP]\n"
   initialize-globals
   initialize-train
   initialize-exits
   initialize-passengers
   ; initialize-fire
   reset-ticks
end

to initialize-globals
   set exit1           patch 64 -13
   set exit2           patch 13 -54
   set exits-list    ( list exit1 exit2 )
   set exit-probabilities (list 0.5 0.5)
end

to initialize-train
   import-pcolors "images/ambiente.png"
   ask patches [
     if pcolor = 86.6 [set pcolor cyan]
     if pcolor =  0   [set pcolor black]
     if pcolor = 64.3 [set pcolor green]
     if pcolor =  9.9 [set pcolor white]

     set fire? false
     set accessible? false ; 默认所有patch不可达
   ]

   ask patches with [pcolor = white] [
     set accessible? true ; 白色patch标记为可达
   ]
end

to initialize-exits
  set exit1 patch 64 -13
  set exit2 patch 13 -54
  set exits-list (list exit1 exit2)
end

to initialize-passengers
  create-passengers passenger-count [
    set shape "person business"
    set size 2
    set color yellow
    set in-seat? false
    set safe? false
    set dead? false
    set panic? true
    set current-heading 0
    set my-exits-list []
    set target-exit nobody

    ; 随机放置在可达patch上
    let target one-of patches with [accessible?]
    move-to target
    set target-exit choose-exit patch-here
    update-exit-probabilities self
  ]
end

to-report choose-exit [current-position]
   let possible-exits        []
   let shortest-distance 10000
   let nearest-exit          nobody

   foreach exits-list [ exitUnderTest ->
           let exit-distance distance exitUnderTest

           if  exit-distance < shortest-distance [
               set shortest-distance exit-distance
               set nearest-exit      exitUnderTest
               set possible-exits    []
           ]

           if  exit-distance = shortest-distance [
               set possible-exits lput exitUnderTest possible-exits ; 直接存储patch对象，减少转换错误
           ]
   ]

   if length possible-exits = 0 [
       print "No exits found."
       report nobody
   ]

   ; 按权重选择出口
   let lucky-exit one-of weighted-n-of 1 possible-exits exit-probabilities
   set target-exit lucky-exit

   ; 计算PP集合并选择LPP
   let pp-list neighbors4 of lucky-exit with [accessible?]
   let M count pp-list
   let lpp ifelse-value (M > 0) [one-of pp-list] [lucky-exit]
   
   face lpp
   set my-exits-list lput lucky-exit my-exits-list

   report lucky-exit ; 返回出口作为长期目标
end

to update-exit-probabilities [passenger1]
  let kie 1.5
  ; 修正参数引用错误：使用传入的passenger1而非未定义的passenger
  let initial-exit [target-exit] of passenger1
  let initial-exit-index position initial-exit exits-list
  if initial-exit-index = false [
    print "Error: Exit not found in exits-list"
    stop
  ]
  let initial-exit-probability item initial-exit-index exit-probabilities
  let pie kie * initial-exit-probability

  if pie > 1 [ set pie 1 ]
  let delta-pi pie - initial-exit-probability

  let updated-exit-probabilities []
  foreach exit-probabilities [p ->
    let index position p exit-probabilities
    if index = initial-exit-index [
      set updated-exit-probabilities lput pie updated-exit-probabilities
    ] [
      let pje p - (p / (1 - initial-exit-probability)) * delta-pi
      ; 确保概率不小于0
      if pje < 0 [ set pje 0 ]
      set updated-exit-probabilities lput pje updated-exit-probabilities
    ]
  ]
  set exit-probabilities updated-exit-probabilities
end

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; FUNZIONI GO ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to go
  type "----------------------------[GO.tick]\n"
  ask passengers [
    if panic? and not safe? [
      ; 仅未到达出口或其邻域时重新选择目标
      if not (patch-here = target-exit or member? patch-here neighbors4 of target-exit) [
        set target-exit choose-exit patch-here
      ]
      face target-exit
    ]
    move
  ]
  tick
end

to move
  if panic? and not safe? [
    let next-patch patch-ahead 1
    ; 确保下一个patch存在、可达且无其他乘客
    if next-patch != nobody and [accessible?] of next-patch and not any? other passengers-here [
      move-to next-patch
      ; 到达出口标记为安全
      if member? patch-here exits-list [
        set safe? true
        set color green
      ]
    ]
  ]
end

额外修复点 #

• 修正update-exit-probabilities中的参数引用错误，避免变量未定义；
• 在choose-exit中直接存储patch对象而非坐标列表，减少转换错误；
• 增加概率下限判断，避免exit-probabilities出现负值。

内容的提问来源于stack exchange，提问作者accismns