luis-r-izquierdo_agent-based-evolutionary-game-dynamics/schelling-sakoda.nlogo
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; GNU GENERAL PUBLIC LICENSE ;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; Schelling-Sakoda model of spatial segregation.
;; Schelling-Sakoda model of spatial segregation is a milestone in the study of emergent
;; global phenomena based on local social interactions
;; (Sakoda 1949, 1971; Schelling 1969, 1971, 1978).
;; Schelling-Sakoda model illustrates how clearly distinctive patterns
;; of spatial segregation (e.g. ghettos) can emerge even
;; if individuals are only weakly segregationist.
;;
;; Sakoda, J. M. (1949) Minidoka: An Analysis of Changing Patterns of Social Behavior.
;;   PhD thesis, University of California.
;; Sakoda, J. M. (1971) The Checkerboard Model of Social Interaction.
;;  Journal of Mathematical Sociology, 1(1):119–132.
;;  https://doi.org/10.1080/0022250X.1971.9989791
;; Schelling, T. C. (1969) Models of Segregation (RAND Memorandum RM-6014-RC).
;;   Technical report, RAND Corporation, Santa Monica, California, May 1969.
;;   http:// www.rand.org/pubs/research_memoranda/RM6014.html.
;; Schelling, T. C. (1971) Dynamic Models of Segregation.
;;   Journal of Mathematical Sociology, 1(2), pp. 143-186.
;;   https://doi.org/10.1080/0022250X.1971.9989794
;; Schelling, T. C. (1978) Micromotives and macrobehavior.
;;   New York: Norton.
;;
;; Copyright (C) 2018 Luis R. Izquierdo, Segismundo S. Izquierdo,
;;   José M. Galán, José I. Santos & William H. Sandholm
;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License
;; as published by the Free Software Foundation; either version 3
;; of the License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; if not, write to the Free Software
;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
;;
;; Contact information:
;; Luis R. Izquierdo
;;   University of Burgos, Spain.
;;   e-mail: lrizquierdo@ubu.es

;;;;;;;;;;;;;;;;;
;;; VARIABLES ;;;
;;;;;;;;;;;;;;;;;

globals [
  avg-%-similar     ;; the average proportion (across agents) of an agent's
                    ;; neighbours that are the same color as the agent.
  %-unhappy-agents  ;; percentage of unhappy agents
]

turtles-own [
  happy?         ;; indicates whether at least %-similar-wanted percent
                 ;; of my neighbours are the same colour as me.
  n-of-my-nbrs   ;; number of neighbours
  similar-nbrs   ;; number of neighbours with the same colour as me
]

;;;;;;;;;;;;;;;;;;;;;;;;
;;; SETUP PROCEDURES ;;;
;;;;;;;;;;;;;;;;;;;;;;;;

to startup
  clear-all
  setup-agents
  do-plots-and-statistics
  reset-ticks
end

to setup-agents
  if number-of-agents >= count patches [
    user-message (word "This grid only has room for " (count patches - 1) " moving agents.")
    stop
  ]

  ;; create agents on random cells
  set-default-shape turtles "person"
  ask n-of number-of-agents patches
    [ sprout 1 [set color cyan] ]
  ;; turn half the agents green
  ask n-of (number-of-agents / 2) turtles
    [ set color orange ]

  ask turtles [update-happiness]
end

;;;;;;;;;;;;;;;;;;;;;;
;;; MAIN PROCEDURE ;;;
;;;;;;;;;;;;;;;;;;;;;;

to go
  if all? turtles [happy?] [stop]
  ask one-of turtles with [not happy?] [move]
  do-plots-and-statistics
  tick
end

;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; AGENTS' PROCEDURES ;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;

to move
  let nbrs-before turtles-on neighbors
  move-to one-of patches with [not any? turtles-here]

  ;; now update agents' happiness, but ask only those
  ;; agents whose happiness may have changed.
  ask nbrs-before [update-happiness]
  ask turtles-on neighbors [update-happiness]
  update-happiness
end

to update-happiness
  let my-nbrs (turtles-on neighbors)
  set n-of-my-nbrs (count my-nbrs)
  set similar-nbrs (count my-nbrs with [color = [color] of myself])
  set happy? similar-nbrs >= (%-similar-wanted * n-of-my-nbrs / 100)
end

;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; PLOTS & STATISTICS ;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;

to do-plots-and-statistics
  set %-unhappy-agents 100 * (count turtles with [not happy?]) / (count turtles)
  let list-of-%-similar ([similar-nbrs / n-of-my-nbrs] of turtles with [n-of-my-nbrs > 0])
  set avg-%-similar 100 * mean list-of-%-similar

  set-current-plot "%-similar nbrs histogram"
  histogram list-of-%-similar
end

;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Notes on efficiency ;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; This model can be implemented more efficiently.
;; In particular, the following two lines of code
;; make many computations that could be saved:
;;
;; ask one-of turtles with [not happy?] [move]
;;  (we could keep a list of turtles that are not happy)
;;
;; move-to one-of patches with [not any? turtles-here]
;;  (we could define a patch-variable turtle-here?
;;   to keep track of whether each patch is empty or not)
@#$#@#$#@
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525
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MONITOR
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330
348
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% unhappy
%-unhappy-agents
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MONITOR
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avg % similar
avg-%-similar
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PLOT
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Avg Percentage Similar Nbrs
time
%
0.0
5.0
0.0
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true
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"" ""
PENS
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PLOT
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Percentage Unhappy Agents
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"" ""
PENS
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SLIDER
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number-of-agents
number-of-agents
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400
266.0
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NIL
HORIZONTAL

SLIDER
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214
183
%-similar-wanted
%-similar-wanted
0
100
60.0
1
1
%
HORIZONTAL

BUTTON
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90
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setup
startup
NIL
1
T
OBSERVER
NIL
NIL
NIL
NIL
1

BUTTON
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go
go
T
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T
OBSERVER
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0

BUTTON
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go once
go
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OBSERVER
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PLOT
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%-similar nbrs histogram
%-similar
#-agents
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"" ""
PENS
"default" 0.1 1 -16777216 true "" ""

MONITOR
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NIL
ticks
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1
14

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airplane
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arrow
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box
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Line -16777216 false 150 135 15 75
Line -16777216 false 150 135 285 75

bug
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Circle -7500403 true true 110 127 80
Circle -7500403 true true 110 75 80
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Polygon -7500403 true true 162 150 200 105 245 90 275 90 290 105 290 135 275 180 260 195 215 195 162 165
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Line -16777216 false 150 105 195 60
Line -16777216 false 150 105 105 60

car
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Circle -7500403 true true 195 195 58

circle
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circle 2
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cow
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Polygon -7500403 true true 25 114 16 195 9 204 23 213 25 200 39 123

cylinder
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Circle -7500403 true true 0 0 300

dot
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face happy
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face neutral
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Circle -16777216 true false 60 75 60
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face sad
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Circle -16777216 true false 180 75 60
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fish
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Circle -16777216 true false 215 106 30

flag
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Polygon -7500403 true true 90 150 270 90 90 30
Line -7500403 true 75 135 90 135
Line -7500403 true 75 45 90 45

flower
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Polygon -10899396 true false 135 120 165 165 180 210 180 240 150 300 165 300 195 240 195 195 165 135
Circle -7500403 true true 85 132 38
Circle -7500403 true true 130 147 38
Circle -7500403 true true 192 85 38
Circle -7500403 true true 85 40 38
Circle -7500403 true true 177 40 38
Circle -7500403 true true 177 132 38
Circle -7500403 true true 70 85 38
Circle -7500403 true true 130 25 38
Circle -7500403 true true 96 51 108
Circle -16777216 true false 113 68 74
Polygon -10899396 true false 189 233 219 188 249 173 279 188 234 218
Polygon -10899396 true false 180 255 150 210 105 210 75 240 135 240

house
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Rectangle -16777216 true false 120 210 180 285
Polygon -7500403 true true 15 120 150 15 285 120
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leaf
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line
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line half
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pentagon
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person
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Rectangle -7500403 true true 127 79 172 94
Polygon -7500403 true true 195 90 240 150 225 180 165 105
Polygon -7500403 true true 105 90 60 150 75 180 135 105

person farmer
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Polygon -7500403 true true 105 90 120 195 90 285 105 300 135 300 150 225 165 300 195 300 210 285 180 195 195 90
Polygon -1 true false 60 195 90 210 114 154 120 195 180 195 187 157 210 210 240 195 195 90 165 90 150 105 150 150 135 90 105 90
Circle -7500403 true true 110 5 80
Rectangle -7500403 true true 127 79 172 94
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Polygon -6459832 true false 116 4 113 21 71 33 71 40 109 48 117 34 144 27 180 26 188 36 224 23 222 14 178 16 167 0
Line -16777216 false 225 90 270 90
Line -16777216 false 225 15 225 90
Line -16777216 false 270 15 270 90
Line -16777216 false 247 15 247 90
Rectangle -6459832 true false 240 90 255 300

person graduate
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Circle -7500403 true true 110 5 80
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Polygon -8630108 true false 90 19 150 37 210 19 195 4 105 4
Polygon -8630108 true false 120 90 105 90 60 195 90 210 120 165 90 285 105 300 195 300 210 285 180 165 210 210 240 195 195 90
Polygon -1184463 true false 135 90 120 90 150 135 180 90 165 90 150 105
Line -2674135 false 195 90 150 135
Line -2674135 false 105 90 150 135
Polygon -1 true false 135 90 150 105 165 90
Circle -1 true false 104 205 20
Circle -1 true false 41 184 20
Circle -16777216 false false 106 206 18
Line -2674135 false 208 22 208 57

plant
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0
Rectangle -7500403 true true 135 90 165 300
Polygon -7500403 true true 135 255 90 210 45 195 75 255 135 285
Polygon -7500403 true true 165 255 210 210 255 195 225 255 165 285
Polygon -7500403 true true 135 180 90 135 45 120 75 180 135 210
Polygon -7500403 true true 165 180 165 210 225 180 255 120 210 135
Polygon -7500403 true true 135 105 90 60 45 45 75 105 135 135
Polygon -7500403 true true 165 105 165 135 225 105 255 45 210 60
Polygon -7500403 true true 135 90 120 45 150 15 180 45 165 90

square
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square 2
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star
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target
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Circle -7500403 true true 60 60 180
Circle -16777216 true false 90 90 120
Circle -7500403 true true 120 120 60

tree
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Rectangle -6459832 true false 120 195 180 300
Circle -7500403 true true 65 21 108
Circle -7500403 true true 116 41 127
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Circle -7500403 true true 104 74 152

triangle
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triangle 2
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Circle -16777216 true false 234 174 42
Rectangle -7500403 true true 181 185 214 194
Circle -16777216 true false 144 174 42
Circle -16777216 true false 24 174 42
Circle -7500403 false true 24 174 42
Circle -7500403 false true 144 174 42
Circle -7500403 false true 234 174 42

turtle
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Polygon -10899396 true false 132 85 134 64 107 51 108 17 150 2 192 18 192 52 169 65 172 87
Polygon -10899396 true false 85 204 60 233 54 254 72 266 85 252 107 210
Polygon -7500403 true true 119 75 179 75 209 101 224 135 220 225 175 261 128 261 81 224 74 135 88 99

wheel
false
0
Circle -7500403 true true 3 3 294
Circle -16777216 true false 30 30 240
Line -7500403 true 150 285 150 15
Line -7500403 true 15 150 285 150
Circle -7500403 true true 120 120 60
Line -7500403 true 216 40 79 269
Line -7500403 true 40 84 269 221
Line -7500403 true 40 216 269 79
Line -7500403 true 84 40 221 269

x
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Polygon -7500403 true true 270 75 225 30 30 225 75 270
Polygon -7500403 true true 30 75 75 30 270 225 225 270
@#$#@#$#@
NetLogo 6.2.2
@#$#@#$#@
@#$#@#$#@
@#$#@#$#@
<experiments>
  <experiment name="experiment" repetitions="10000" runMetricsEveryStep="false">
    <setup>startup</setup>
    <go>go</go>
    <exitCondition>all? turtles [happy?]</exitCondition>
    <metric>avg-%-similar</metric>
    <enumeratedValueSet variable="number-of-agents">
      <value value="266"/>
    </enumeratedValueSet>
    <steppedValueSet variable="%-similar-wanted" first="20" step="5" last="70"/>
  </experiment>
</experiments>
@#$#@#$#@
@#$#@#$#@
default
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Line -7500403 true 150 150 90 180
Line -7500403 true 150 150 210 180
@#$#@#$#@
0
@#$#@#$#@
