I am essentially trying to combine elements of the 'Segregation' model and 'Rebellion' model to form a model that is representative of alliance forming.
Here is what I have so far- when I attempt to run it I receive the error: THREATS breed does not own variable ACTIVE? error while threat 0 running ACTIVE? called by procedure GO called by Button 'go'
breed [ agents an-agent]
breed [ threats threat ]
globals [
k ; factor for determining attack probability
threshold ; by how much must D - BS > A to make a state burden share
percent-similar ; on the average, what percent of a turtle's neighbors
; are the same color as that turtle? Likely to ally
percent-unhappy ; what percent of the turtles are unhappy? Or percieve threats?
visualization
]
agents-own [
allied-states ; R, fixed for the agent's lifetime, ranging from 0-1 (inclusive)- for each turtle, indicates whether at least %-similar-wanted percent of
; that turtle's neighbors are the same color as the turtle
perceived-threat ; T, also ranging from 0-1 (inclusive)- how many have a turtle of another color?
active? ; if true, then the agent is actively allied
; if false, then the agent is free-riding
conflict ; how many turns in conflict remain? (if 0, the agent is not in conflict)- sum of previous two variables
total-nearby ; sum of previous two variables
]
patches-own [
neighborhood ; surrounding patches within the vision radius
]
to setup
clear-all
; set globals
set k 2.3
set threshold 0.1
ask patches [
; make background a slightly dark gray
set pcolor gray - 1
; cache patch neighborhoods
set neighborhood patches in-radius vision
]
if initial-threats-density + initial-agent-density > 206 [
user-message (word
"The sum of INITIAL-THREATS-DENSITY and INITIAL-AGENT-DENSITY "
"should not be greater than 206.")
stop
]
; create threats
create-threats round (initial-threats-density * .01 * count patches) [
move-to one-of patches with [ not any? turtles-here ]
display-threats
]
; create agents
create-agents round (initial-agent-density * .01 * count patches) [
move-to one-of patches with [ not any? turtles-here ]
set heading 0
set allied-states random-float 1.0
set perceived-threat random-float 1.0
set active? false
set conflict 0
display-agent
]
; start clock and plot initial state of system
reset-ticks
end
to go
if all? turtles [ active? ] [ stop ]
move-unhappy-turtles
update-turtles
update-globals
tick
end
; unhappy turtles try a new spot
to move-unhappy-turtles
ask turtles with [ not active? ]
[ find-new-spot ]
end
; move until we find an unoccupied spot
to find-new-spot
rt random-float 360
fd random-float 10
if any? other turtles-here [ find-new-spot ] ; keep going until we find an unoccupied patch
move-to patch-here ; move to center of patch
end
to update-turtles
ask turtles [
; in next two lines, we use "neighbors" to test the eight patches
; surrounding the current patch
set allied-states count (turtles-on neighbors) with [ color = [ color ] of myself ]
set perceived-threat count (turtles-on neighbors) with [ color != [ color ] of myself ]
set total-nearby allied-states + perceived-threat
set active? allied-states >= (percent-similar * total-nearby / 100)
; add visualization here
if visualization = "old" [ set shape "default" set size 1.3 ]
if visualization = "square-x" [
ifelse active? [ set shape "square" ] [ set shape "X" ]
]
]
end
to update-globals
let similar-neighbors sum [ allied-states ] of turtles
let total-neighbors sum [ total-nearby ] of turtles
set percent-similar (similar-neighbors / total-neighbors) * 100
set percent-unhappy (count turtles with [ not active? ]) / (count turtles) * 100
; Agents engaged in conflict have the duration reduced at the end of each clock tick
ask agents [ if conflict > 0 [ set conflict conflict - 1 ] ]
; update agent display
ask agents [ display-agent ]
ask threats [ display-threats ]
; advance clock and update plots
tick
end
; AGENT AND THREAT BEHAVIOR
; move to an empty patch
to move ; turtle procedure
if movement? or breed = threats [
; move to a patch in vision; candidate patches are
; empty or contain only jailed agents
let targets neighborhood with [
not any? threats-here and all? agents-here [ conflict > 0 ]
]
if any? targets [ move-to one-of targets ]
]
end
; AGENT BEHAVIOR
to determine-behavior
set active? (burden-sharing - allied-states * estimated-conflict-probability > threshold)
end
to-report burden-sharing
report perceived-threat * (1 - alliance-protection)
end
to-report estimated-conflict-probability
let t count (threats-on neighborhood)
let a 1 + count (agents-on neighborhood) with [ active? ]
; See Info tab for a discussion of the following formula
report 1 - exp (- k * floor (t / a))
end
to alliance
if any? threats [attack]
set active? true
end
; THREAT BEHAVIOR
to attack
if any? (agents-on neighborhood) with [ active? ] [
; arrest suspect
let suspect one-of (agents-on neighborhood) with [ active? ]
move-to suspect ; move to patch of the jailed agent
ask suspect [
set active? false
set conflict random conflict-term
set color pink
]
]
end
; VISUALIZATION OF AGENTS AND COPS
to display-agent ; agent procedure
set color cyan
set shape "triangle"
end
to display-active?
set color pink
set shape "triangle"
end
to display-threats
set color red
set shape "circle 2"
end
