CODEWITHSUNDEEP
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lyh198
lyh198

Reputation: 71

Create clusters of patches without changing occurrence

I am writing a Netlogo model which only involves patches. I have managed to create a landscape consisting of patches of 6 different colours (each representing a different vegetation in my project) according to probability. So red patches have a probability of 10% to occur on each patch, yellow 5%, brown 20% and so on.

An example of my code where this probability is set up:

    let i random-float 1
    ifelse i + random-float 0.1 <= 0.8 ;random 0.1 threshold for environmental noise
      [ set pcolor green ]
      [ ifelse i + random-float 0.1 <= 0.9
        [ set pcolor yellow ]
        [ set pcolor blue ] ]

However, this creates a random pattern for each colour. But I would like to create a clustered spatial pattern for one of them.Specifically, in my landscape, I want the proportion of brown patches to be 50%. But if I were to set this 50% probability for every patch, the brown patches will be randomly distributed. How do I get it to occupy 50% of my landscape, but appear in a clustered pattern?

I tried creating the clustered pattern using the Moore neighbourhood, but that obviously changes the proportion of brown patches.

I hope this is somewhat clear. Thanks for any help in advance.

Upvotes: 1

Views: 321

Answers (1)

Alan
Alan

Reputation: 9610

You could seed based on your weights and then grow around the seeds. Here is a different approach: color all patches based on your weights, and then cluster the colors.

extensions [rnd]    ;use the rnd extension
globals [threshold]

to setup
  ca
  set threshold 2
  let _cw [[red 10] [yellow 20] [blue 70]]   ;colors with weights
  ask patches [set pcolor first rnd:weighted-one-of-list _cw [last ?]]
  repeat 20 [cluster]  ;adjust to taste
end

to cluster
  ask patches [
    if unhappy? [
      swap-pcolor
    ]
  ]
end


to swap-pcolor
  let _c pcolor
  let _p one-of neighbors with [pcolor != [pcolor] of myself]
  set pcolor [pcolor] of _p
  ask _p [set pcolor _c]
end

to-report unhappy?
  let _ct count neighbors with [pcolor = [pcolor] of myself]
  report (_ct < threshold)
end

Upvotes: 1

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