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I spent all afternoon trying to work out with a part of my code and I don't seem to be getting anywhere. Basically, I'm trying to create a social network on model setup. Each person in the model starts off with a set of people that are nearby to them people-nearby. It is from this set that people choose who to connect with:

create-people population-size
[
  set people-nearby turtle-set other people in-radius neighborhood-radius
]

to create-network
  let num-links round (average-node-degree * population-size) / 2  

  while [ count links < num-links and count people with [length sort people-nearby > 0] > 0 ]

  [ ask one-of people
    [ *... initiate probabilistic link creation process...*
     create-unlink-with chosen-friend

Once person A has connected to someone (ie. person B), person B is removed from person A's people-nearby set. I'm having trouble with this portion of the code where the people-nearby set is updated by excluding all nearby people that are members of the unlink-neighbors set (i.e., those to whom person A is already connected - this set including person B):

        ifelse count turtle-set people-nearby > 1  
        [ let nearby-people-not-linked-to-me  ( turtle-set people-nearby with [ not member? self [ turtle-set unlink-neighbors ] of myself ] ) 
          set people-nearby nearby-people-not-linked-to-me ]
        [ set people-nearby [ ] ]

For some reason this error keeps popping up: "WITH expected input to be an agentset but got the list [(person 0) (person 1) (person 3) (person 4)] instead." whenever
people-nearby with [ not member? self [ turtle-set unlink-neighbors ] of myself is called.

I looked up so many posts but can't seem to get the form of the argument right so that it stops showing this error.

Can anyone help me fix this please? (Oh and it's my first post so apologies if I haven't set up the issue properly)

skivvy
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    Duplicate of http://stackoverflow.com/questions/8425518/netlogo-two-agentsets-operations – Alan Mar 17 '17 at 23:25
  • Yeah, I looked at this thread and couldn't seem to work out how to stop the error message from being called by my code. Sorry about this. – skivvy Mar 18 '17 at 17:11

1 Answers1

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When you submit code, try to submit what is needed to recreate your problem- check out the asking help page, and specifically the section on helping others reproduce your problem. As is, I think your problem comes from using turtle-set. That primitive is mostly used to combine agentsets, not to query them. So in your line:

( turtle-set people-nearby with [ not member? self [ turtle-set unlink-neighbors ] of myself ] )

there is an syntax issue related to turtle-set. The error itself is saying that you have not returned an agentset but a list of agents, which behave differently.

If I understand correctly, you want all people to have a variable that contains all people within a radius of themselves: "people-nearby". Then, you want the people to form a link with one of their "neighbor" turtles. Finally, you want the people to update their "people-nearby" variable to exclude the person to whom they just formed a link. Below is some code with comments where I tried to follow those steps- obviously your variables will be different, but it may get you started. Let me know if I need to clarify anything or if I missed a step.

breed [ people person ]
turtles-own [ people-nearby ]


to setup 
  ca
  reset-ticks
  create-people 70  [
    setxy (random 30 - 15) (random 30 - 15)
  ]

  ; do this after all turtles have spawned
  ask people [
    set people-nearby other people in-radius 3
  ]

end


to create-links

  let num-links 10

  ;; Create a temporary agentset out of turtles that have people nearby
  let turtles-with-neighbors turtles with [ any? people-nearby ]

  ; ask some number of the temporary agentset:
  ask n-of num-links turtles-with-neighbors [

    ;; This just makes it easy to identify the turtle that causes the link
    ask patches in-radius 3 [
      set pcolor white
    ]

    ; create a link to one of the nearby people
    create-link-to one-of people-nearby
    ; newly set people-nearby to only include turtles in radius
    ; that are not linked-to from the currently acting turtle
    set people-nearby other people in-radius 3 with [ not member? self [ out-link-neighbors ] of myself  ]
    ask people-nearby [ set size 0.5 ]
  ]

end
Community
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Luke C
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  • Thanks so much, Luke, and sorry for not setting up the problem properly. I guess, given that I defined `people-nearby` as `set people-nearby other people in-radius 3` up front, I thought I could just call on that agentset in redefining the new `people-nearby` which excludes anyone linked to the acting person i.e., `set people-nearby people-nearby with [ not member? self [ out-link-neighbors ] of myself ]` Why is it wrong to do that? In any case, your comments helped resolve that error so thank you. Now, for some reason, people are connecting to others that are not within their in-radius. – skivvy Mar 18 '17 at 17:09
  • No worries! Your question still made sense- it just means that your *exact* error may not be the one that others get. As far as "why it is wrong," I don't think that your comment code is wrong at all- your original line that used `turtle-set` had syntax errors. It's definitely better to say `set people-nearby people-nearby with [ not member? self [ out-link-neighbors ] of myself ]` (I oversimplified, sorry!). Your connecting error may be due to the order that turtles move, create "people-nearby", and create links. Make sure all turtles complete each task before any turtles move to the next. – Luke C Mar 18 '17 at 20:55