在Netlogo中，我可以要求补丁在乌龟环境中做什么吗？

Question

I need to have a patches-own update as each turtle moves within a command, using the ask turtles context. So, essentially I am wanting to ask the patches to do something within a turtle context. I know that you can have the turtles access patch variables while on that specific patch, but what I need is for the patches to to calculate "marginal-value" (a patch variable I made up) of all patches including ones that don't have turtles. My goal is to have the marginal value update every single time a turtles goes to move with in a "ask turtles" command. So the fact that turtles can access the patch that they are on patch variable doesn't seem helpful in this situation. Is this possible to do? If so, how would you suggest I go about that?

For example what I have now doesn't work, but might be helpful in understanding what I am trying to do:

 ask turtles
  [ ask patches
    [ calculate-marginal-vaule ]]

to calculate-marginal-vaule
   ifelse
    count turtles-here > 0
    [ set possible-consumption ( quality ) / ( strength-of-competition * count turtles-here ) ]
    [ set possible-consumption quality ]
  set marginal-value mean [ possible-consumption ] of patches
end

Answer 1

NetLogo specifically bans code like ask turtles [ ask patches [ <do something> ] ] because code of this format is almost always an error (and is a major source of inefficiency). You can, however, ask a subset of patches that meet some condition to do something, as in the following code.

to testme
  clear-all
  create-turtles 10
  ask patches [ set pcolor 15 ]
  ask turtles
  [ ask patches with [ pxcor >= 0 ] [ set pcolor pcolor + 5 ]
  ]
end

If you have 10 turtles, then ask turtles [ ask patches [ ] ] would make the patches do the actions 10 times. Is that actually what you want? There is no problem accessing information from all patches, just doing some action.

Answer 2

You can get around the limitation explained by Jen if you turn the special patches agentset into a "regular" patch agentset using the patch-set reporter:

ask turtles [
  ask patch-set patches [
    calculate-marginal-value
  ]
]

Now whether or not it is wise to do so is another question.

I'm not sure I understand the problem you are trying to solve well enough to be able to tell in your case, but I can tell you that what you're currently trying to do will be very computationally expensive. You should at least try to think of another way of approaching the problem if you can.