Granovetter's threshold model of collective behaviour

turtles-own [threshold riot?]

to setup
  ca
  set-default-shape turtles "circle"
  if max-threshold < min-threshold [
    print "min-threshold should be smaller than max-threshold"
    stop
  ]
  create-agents
  reset-ticks
end 

to go
  ask turtles [
    let prop-rioting 100 * count link-neighbors with [riot? = true] / count link-neighbors
    if prop-rioting >= threshold [
      set riot? true
      set color red
    ]
  ]
  tick
end 

to create-agents

  let min-threshold-n min-threshold * number-of-agents / 100
  let max-threshold-n max-threshold * number-of-agents / 100
  let mean-threshold-n mean-threshold * number-of-agents / 100
  let sd-threshold-n sd-threshold * number-of-agents / 100

  crt number-of-agents [
    set riot? false
    set color blue
    if threshold-distribution = "uniform" [set threshold (min-threshold + random (max-threshold - min-threshold))]
    if threshold-distribution = "normal" [set threshold round (random-normal mean-threshold sd-threshold)]
    if threshold < 0 [set threshold 0]
    if threshold > 100 [set threshold 100]
  ]

  ;layout-circle (sort turtles) (max-pxcor - 1)
  arrange-turtles

  ; random network of grade 2 * number of links
  if network = "random" [
    ask turtles [create-links-with n-of number-of-links other turtles with [link-with myself = nobody]]
  ]

  ; small-world network
  if network = "small-world" [
    let max-who 1 + max [who] of turtles
    let sorted sort ([who] of turtles)
    foreach sorted[ [?1] ->
      ask turtle ?1 [
        let i 1
        repeat number-of-links [
          create-link-with turtle ((?1 + i) mod max-who)
          set i i + 1
        ]
      ]
    ]
    repeat round (rewire-prop * number-of-agents) [
      ask one-of turtles [
        ask one-of my-links [die]
        create-link-with one-of other turtles with [link-with myself = nobody]
      ]
    ]
  ]

  ; fully connected network
  if network = "fully connected" [
    ask turtles [create-links-with other turtles with [link-with myself = nobody]]
  ]
end 

to arrange-turtles ;similar to layout-circle (sort turtles) (max-pxcor - 1)
  let the-turtles sort [who] of turtles
  let angle 360 / number-of-agents
  let dist max-pxcor - 1
  let i 0
  foreach the-turtles [ [?1] ->
    ask turtle ?1 [
      setxy (dist * cos (angle * i)) (dist * sin (angle * i))
    ]
    set i i + 1
  ]
end