globals [n-of-changers]

patches-own
[
  vote     ;; my vote (0 or 1)
  total    ;; sum of votes around me
  oldvote  ;; previous vote
]

to setup
  ca
  ask patches
    [ifelse (random-float 100) <  initial-percent-red  [set vote 0] [set vote 1]
      recolor-patch ]
end

to go
  ask patches
    [ set total (sum [vote] of neighbors) 
      set oldvote vote]
  ;; use two ask patches blocks so all patches compute "total"
  ;; before any patches change their votes
  ask patches [
      let majority (max list total (8 - total))
      let actionstring (word "action" majority "-" (8 - majority))
      let strategy runresult actionstring 
      set vote newvote vote total strategy
      recolor-patch ]
      set n-of-changers sum [abs (vote - oldvote)] of patches
      plot n-of-changers
end

to recolor-patch  ;; patch procedure
  ifelse vote = 0
    [ set pcolor red ]
    [ set pcolor blue ]
end

to-report newvote [myoldvote neighbortotal mystrategy]
     if mystrategy = "with majority" [report ifelse-value (total > 4) [1] [0]]
     if mystrategy = "keep last decision" [report myoldvote]
     if mystrategy = "change last decision" [report (1 - myoldvote)]
     if mystrategy = "oppose majority" [report ifelse-value (total > 4) [0] [1]] 
end
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GRAPHICS-WINDOW
432
10
644
243
50
50
2.0
0
10
1
1
1
0
1
1
1
-50
50
-50
50
0
0
1
ticks

CC-WINDOW
5
345
653
440
Command Center
0

BUTTON
28
13
83
46
setup
setup
NIL
1
T
OBSERVER
NIL
NIL
NIL
NIL

BUTTON
90
13
145
46
NIL
go
T
1
T
OBSERVER
NIL
NIL
NIL
NIL

MONITOR
447
280
536
325
blue patches
count patches with\n  [ pcolor = blue ]
0
1
11

MONITOR
547
280
635
325
red patches
count patches with\n  [ pcolor = red ]
0
1
11

CHOOSER
28
120
204
165
action5-3
action5-3
"with majority" "keep last decision" "change last decision" "oppose majority"
0

CHOOSER
27
173
203
218
action6-2
action6-2
"with majority" "keep last decision" "change last decision" "oppose majority"
0

CHOOSER
27
227
203
272
action7-1
action7-1
"with majority" "keep last decision" "change last decision" "oppose majority"
0

CHOOSER
28
286
204
331
action8-0
action8-0
"with majority" "keep last decision" "change last decision" "oppose majority"
0

CHOOSER
29
69
205
114
action4-4
action4-4
"keep last decision" "change last decision"
0

SLIDER
232
69
404
102
initial-percent-red
initial-percent-red
0
100
50
1
1
NIL
HORIZONTAL

PLOT
218
178
418
328
Changers
NIL
NIL
0.0
10.0
0.0
10.0
true
false
PENS
"default" 1.0 0 -16777216 true

MONITOR
287
114
385
159
percent-red
100 * count patches with [vote = 0] / (count patches)
1
1
11

@#$#@#$#@
WHAT IS IT?
-----------
This model is a simple cellular automaton that simulates voting distribution by having each patch take a "vote" of its eight surrounding neighbors, then perhaps change its own vote according to the outcome.


HOW TO USE IT
-------------
Click the SETUP button to create arandom distribution of blue and red patches.  
The percent-red slider allows you to set the initial percentage of red cells
(approximately).
Click GO to run the simulation.

The 8 neighbors of a cell can have a 4-4 tie, a 5-3 majority, a 6-2 majority, a 7-1 majority, or a 8-0 majority.
The choosers allow you to define the cell's behaviour for each of the possible majorities.
The cell can
1) go with the majority
2) stay with it's last decision
3) change it's last decision
4) vote against the majority



THINGS TO NOTICE
----------------
Watch how any setup quickly settles to a static state when voters go for the majority if there is one.

Watch what happens when the voter only switches when there is no majority (i.e. a 4-4 tie)?  
How is the result different?

Watch what happens when the voter goes for the majority for small majorities,
but opposes strong majorities.

RELATED MODELS
--------------
Ising (a physics model, but the rules are very similar)
 
CREDITS AND REFERENCES
----------------------
The original model is described in Rudy Rucker's "Artificial Life Lab", published in 1993 by Waite Group Press.
It has been modified by Erich Neuwirth, University of Vienna
To refer to this model in academic publications, please use: Wilensky, U. (1998). NetLogo Voting model. http://ccl.northwestern.edu/netlogo/models/Voting. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.
In other publications, please use: Copyright 1998 Uri Wilensky. All rights reserved. See http://ccl.northwestern.edu/netlogo/models/Voting for terms of use.
 



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NetLogo 4.0.4
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