One Turtle Per Patch Example

One Turtle Per Patch Example preview image

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Uri_dolphin3 Uri Wilensky (Author)

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Model group CCL | Visible to everyone | Changeable by group members (CCL)
Model was written in NetLogo 5.0.4 • Viewed 8965 times • Downloaded 360 times • Run 1 time
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;; SET UP THE WORLD

to setup
  clear-all
  ;; Color the patches so they're easier to see
  ask patches [ set pcolor random-float 2 ]
  ;; The easiest way to ensure that we start with only one
  ;; turtle per patch is to use "sprout" to have the patches
  ;; create the turtles
  ask n-of num-turtles patches [ sprout 1 ]
  reset-ticks
end 

;;; ABOUT THE STRATEGIES

;; Which of the following techniques is appropriate for your model
;; depends on what you're modeling.  The different techniques have
;; different pros and cons.  For example, how far the turtles move
;; each time varies with the different strategy:
;;
;; Strategy #1: A turtle sometimes moves 1, sometimes doesn't move
;; at all.  Even if it moves, it sometimes still remains on the same
;; patch.
;;
;; Strategy #2: A turtles always moves at least 1, but it may move
;; an indefinitely large distance if it takes it a long time to find
;; an empty patch.
;;
;; Strategy #3: If there is an adjacent empty patch, the turtle will
;; always move to it, otherwise it will stay put.  Turtles always
;; occupy the center of patches.
;;
;; These aren't the only possible strategies -- there are lots of
;; possible ways you could modify or combine these strategies.

;;;

;; TURTLE STRATEGY #1:
;; If the patch ahead has no other turtles on it, then move onto
;; it, otherwise turn a random direction and wait until next time
;; before trying to move again.  A subtle point here is that "fd 1"
;; doesn't always take you to a new patch, because along the
;; diagonal, a patch is 1.414... units big.

to go-if-empty-ahead
  ask turtles [
    ifelse not any? other turtles-on patch-ahead 1
      [ fd 1 ]
      [ rt random 360 ]
  ]
  tick
end 

;; TURTLE STRATEGY #2:
;; Check neighboring patches to see if any are empty.  If any are
;; empty, pick a random empty one and move onto its center.
;; Note that we can't just do "fd 1", since the patch's center
;; might be more than 1 unit away from our current position.

to go-if-empty-nearby
  ask turtles [
    let empty-patches neighbors with [not any? turtles-here]
    if any? empty-patches
      [ let target one-of empty-patches
        face target
        move-to target ]
  ]
  tick
end 

;; TURTLE STRATEGY #3:
;; Keep moving forward until standing on an empty patch.  (The
;; Segregation model in the Models Library uses a variant of
;; this strategy.)  Note that theoretically this could end up
;; stuck in an infinite loop if all the patches the turtle
;; crosses are always occupied, but this is very unlikely
;; to happen in practice.

to go-until-empty-here  ;; turtle procedure
  ask turtles [
    fd 1
    while [any? other turtles-here]
      [ fd 1 ]
  ]
  tick
end 


; Public Domain:
; To the extent possible under law, Uri Wilensky has waived all
; copyright and related or neighboring rights to this model.

There are 10 versions of this model.

Uploaded by When Description Download
Uri Wilensky almost 11 years ago Updated to NetLogo 5.0.4 Download this version
Uri Wilensky over 11 years ago Updated version tag Download this version
Uri Wilensky about 12 years ago Updated to NetLogo 5.0 Download this version
Uri Wilensky over 13 years ago Updated from NetLogo 4.1 Download this version
Uri Wilensky over 13 years ago Updated from NetLogo 4.1 Download this version
Uri Wilensky over 13 years ago Updated from NetLogo 4.1 Download this version
Uri Wilensky over 13 years ago Updated from NetLogo 4.1 Download this version
Uri Wilensky almost 14 years ago Model from NetLogo distribution Download this version
Uri Wilensky almost 14 years ago One Turtle Per Patch Example Download this version
Uri Wilensky almost 14 years ago One Turtle Per Patch Example Download this version

Attached files

File Type Description Last updated
One Turtle Per Patch Example.png preview Preview almost 11 years ago, by Reuven M. Lerner Download

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