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Abhishek Bhatia
Abhishek Bhatia

Reputation: 9796

Netlogo Probabilistic movement by a turtle to surrounding patches

I want a turtle to Probabilistically move to one of the patches in it's neighbors. The value of probability for patch variable. This is quite similar to genetic algorithm selection. I wish to implement any selection technique possible.

UPDATE:

Value of probability of a patch: means the chance of getting that patch selected. So a patch with zero probability have get no chance of getting selected. And a patch with 100 percent probability will always get selected.:

UPDATE2: The following I found I think does so but I think understand it quite:

 report last first filter [first ? >= rand-num] probabilities

The tried this other code,please check if it makes sense:

ask neighbors4[calculate-proabalities]
let patchset neighbors4
  let pick random-float sum [score] of patchset
  let winner nobody
  ask patchset[
    if (is-patch? winner = false)
    [
      ifelse (score > pick)
       [set winner self]
       [set pick pick - score]
       ]
    ]
  report winner

Upvotes: 0

Views: 278

Answers (2)

Nicolas Payette
Nicolas Payette

Reputation: 14972

This is something that can also be achieved with the rnd:weighted-one-of primitive of the Rnd extension:

let winner rnd:weighted-one-of neighbors4 [ [score] of ? ]

Upvotes: 1

Alan
Alan

Reputation: 9610

You are basically repeating code from the Lottery example in the Models Library. (Attribution would be a good idea.) It is unclear why you changed the test for the existence of a winner. I would actually discard it altogether, like this.

to-report local-winner [#candidates]
  ask #candidates [calculate-score]
  let %pick random-float sum [score] of #candidates
  let %winner nobody
  ask #candidates [
    ifelse score > %pick [ 
       set %winner self stop
    ] [ 
       set %pick (%pick - score)
    ] 
  ]
  report %winner
end

ask myturtle [move-to local-winner neighbors4]

Note that this assumes (as in your example code) that a patch can compute its score in isolation. If not, you will need to make appropriate changes. Note also that you cannot simply report out from inside the ask, which one might be tempted to try.

Upvotes: 1

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