netlogo中基于距离的死亡率模型 [英] Distance-based mortality model in netlogo

问题描述

我正在计算netlogo中海龟的累计死亡率，作为海龟(其中100只)从netlogo界面世界中的原点(start-patch)移动的距离的函数.在下面的代码中，"Pass-Away"过程链接到一个称为"space-death"的全局接口开关，该开关在打开时会产生由"Pass-Away-Space"过程承担的基于距离的死亡率，否则保持正常的运行状态.通过称为"Pass-Away-Time"的程序进行的时间步长(tick):

I am calculating cumulative turtle mortality in netlogo as a function of distance moved by turtles (100 of them) from the origin (start-patch) in the netlogo interface world. In the code below the 'Pass-Away' procedure is linked to a global interface switch called "space-death" which when switched on yields said distance-based mortality undertaken by the procedure called "Pass-Away-Space", otherwise maintains regular per-time-step (tick) mortality undertaken by the procedure called "Pass-Away-Time":

    to Pass-Away-Time
  ask turtles [
    let chances 1 - exp( -1 * mortality * ticks )
    if chances >= 1 [die
      set dead-count dead-count + 1
    ]
  ]
end

to Pass-Away-Space
  ask turtles [
  let chances 1 - exp( -1 * mortality * [distance start-patch] of turtles)
    if chances >= 1 [die
      set dead-count dead-count + 1
    ]
  ]
end

to Pass-Away
  ask turtles [
     ifelse space-death [
     Pass-Away-Space][ 
     Pass-Away-Time
     ]
   ]
end

我在执行此操作时遇到两个错误，都可能是由于"Pass-Away-Space"过程的编码问题所致.第一个是，只有观察者可以询问所有乌龟的集合.然后，当我将let chances 1 - exp( -1 * mortality * [distance start-patch] of turtles)移到ask turtles[]括号之外时，此错误才得到解决，只会产生另一个表示**预期输入的错误是一个数字，但得到列表*，后跟一个数字序列.也许是由于对多只海龟调用了死亡率方程中的* [distance start-patch] of turtles部分(这正是我想要达到的目标-让每只随机游走的海龟都使用其距原点的距离来计算其累积的-步死亡率和超过阈值死亡-在不同时间，不同距离的不同海龟在不同时间发生的事件).关于如何解决这个问题有什么想法吗?

I get two errors doing this, both likely due to issues with the coding of the "Pass-Away-Space" procedure. The first is Only the observer can ASK the set of all turtles. Then when I move the let chances 1 - exp( -1 * mortality * [distance start-patch] of turtles) outside of the ask turtles[] brackets this error is resolved only yield another that says ** expected input to be a number but got the list* followed by a sequence of numbers. Perhaps due to the fact that the section of the mortality equation that reads * [distance start-patch] of turtles is invoked for multiple turtles (which is exactly what I want to achieve - have each random-walking turtle use its distance from the origin to calculate its cumulative per-step mortality and die above a threshold - an event that occurs at different times for different turtles at different distances). Any thoughts on how to resolve this?

推荐答案

第一个错误是因为您要所有乌龟都问所有乌龟.从Pass-Away过程开始，并假定space-death设置为TRUE.怎么了?您要求所有乌龟运行Pass-Away-Space过程.也就是说，每只乌龟都会依次运行该程序.该过程的第一步是ask turtles [ ].因此，一只乌龟正在要求所有的乌龟做某事.因此是错误.

The first error is because you are asking all turtles to ask all turtles. Starting with your Pass-Away procedure and assuming space-death is set to TRUE. What happens? You ask all turtles to run the Pass-Away-Space procedure. That is, each turtle will run that procedure in turn. The first step of that procedure is to ask turtles [ ]. So a turtle is asking all turtles to do something. Hence the error.

要修复此问题，您需要重写Pass-Away-Space过程，以便该过程可以运行需要为单个乌龟运行的任何代码(对于Pass-Away-Time类似).您可能想要类似的东西:

To fix it, you need to rewrite the Pass-Away-Space procedure so it runs whatever code needs to be run for a SINGLE turtle (and similarly for Pass-Away-Time). You probably want something like:

to Pass-Away-Space
  if exp( -1 * mortality * [distance start-patch]) < 0
  [ die
    set dead-count dead-count + 1
  ]
end

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