如何在Netlogo中设置来自nest的agentset的标题

我计划做的是让一群代理从世界各地的巢穴蜂拥而至

我使用植绒代码，我有问题，以确定标题的凝聚部分。既然所有的特工都要离开巢穴，我该如何设置他们的方向

编辑代码后出现的错误有：

No heading is defined from a point (0,0) to that same point.
error while turtle 1 running TOWARDS
  called by procedure AVERAGE-HEADING-TOWARDS-FLOCKMATES
  called by procedure COHERE
  called by procedure FLOCK

以下是agentset的代码：

to setup
  clear-all
  let number-of-groups 3
  let turtles-per-group 4  
  create-turtles turtles-per-group * number-of-groups 
    [ set color red  
      set size 1.5  
      set pen-mode "down"
    ]  
  set groups [] ; empty list
  repeat number-of-groups [
    let new-group n-of turtles-per-group turtles with [
      not is-agentset? my-group
    ]
    ask new-group [ set my-group new-group ]
    set groups lput new-group groups
  ]
  reset-ticks
end

to go
ask turtles [flock]
end

这是植绒部分

to flock
  find-flockmates
  if any? flockmates
  [
    find-nearest-neighbor
    ifelse distance nearest-neighbor < minimum-separation
        [ separate ]
        [ align
          cohere ] ]
end

to find-flockmates  ;; turtle procedure
  set flockmates my-group
end

to find-nearest-neighbor ;; turtle procedure
  set nearest-neighbor min-one-of flockmates [distance myself]
end

;;; COHERE

to cohere  
  turn-towards average-heading-towards-flockmates max-cohere-turn
end

to-report average-heading-towards-flockmates  
 let x-component mean [sin (towards myself + 180)] of flockmates
  let y-component mean [cos (towards myself + 180)] of flockmates
  ifelse x-component = 0 and y-component = 0
    [ report heading ]
    [ report atan x-component y-component ]
end

群集
寻找同伴
如果有的话？羊群
[
寻找最近的邻居
ifelse距离最近邻<最小间隔
[分开]
[对齐
凝聚]]
结束
寻找同伴；；海龟手术
把我的小组安排好
结束
寻找最近的邻居；；海龟手术
将最近的邻居min设置为一个羊群伙伴[与自己保持距离]
结束
;;; 凝聚
凝聚
转向平均航向转向flockmates max cohere转向
结束
报告朝向羊群的平均航向
让x-分量表示配偶的[sin（对我+180）]
让y分量表示群友的[cos（朝向我+180）]
如果x分量=0，y分量=0
[报告标题]
[报告x组件和y组件]
结束

我无法更改

的代码，以报告对flockmates的平均航向
，因为这里不能使用flockmates的
对我自己+180）]。有人能帮我吗