Basic model 1: Networks

to simple_net
  ca
   crt 5
   ask turtles [setxy random-xcor random-ycor ]
   ;; turtle 1 creates links with all other turtles
   ;; the link between the turtle and itself is ignored
   ask turtle 0 [ create-links-with other turtles ]
   show count links ;; shows 4
   ;; this does nothing since the link already exists
   ask turtle 0 [ create-link-with turtle 1 ]
   show count links ;; shows 4 since the previous link already existed
   ask turtle 2 [ create-link-with turtle 1 ] 
   show count links ;; shows 5
end 

to make-a-tree
  ca
  set-default-shape turtles "circle"
  crt 6
  ask turtle 0 [ 
    create-link-with turtle 1
    create-link-with turtle 2
    create-link-with turtle 3
  ]
  ask turtle 1 [
    create-link-with turtle 4
    create-link-with turtle 5
  ]  
  ; do a radial tree layout, centered on turtle 0
  layout-radial turtles links (turtle 0)
end 

to make-a-triangle
  ca
  set-default-shape turtles "circle"
  crt 3
  ask turtle 0
  [
    create-links-with other turtles
  ]
  ask turtle 1
  [
    create-link-with turtle 2
  ]
  repeat 30 [ layout-spring turtles links 0.2 5 1 ] ;; lays the nodes in a triangle
end 

to make-a-tutte
  ca
  set-default-shape turtles "circle"
  crt 6
  ask turtle 0 [ 
    create-link-with turtle 1
    create-link-with turtle 2
    create-link-with turtle 3
  ]
  ask turtle 1 [
    create-link-with turtle 4
    create-link-with turtle 5
  ]  
  ; place all the turtles with just one 
  ; neighbor on the perimeter of a circle
  ; and then place the remaining turtles inside 
  ; this circle, spread between their neighbors.
  repeat 10 [ layout-tutte (turtles with [link-neighbors = 1]) links 12 ]
end 


directed-link-breed [red-links red-link]
undirected-link-breed [blue-links blue-link]

to direct-graph
  ca
  crt 5
  ;; create links in both directions between turtle 0
  ;; and all other turtles
  ask turtle 0 [ create-red-links-to other turtles ]
  ask turtle 0 [ create-red-links-from other turtles ]
  show count links ;; shows 8
  ;; now create undirected links between turtle 0 and other turtles
  ask turtle 0 [ create-blue-links-with other turtles ]
  show count links ;; shows 12
  layout-radial turtles links (turtle 0)
end 

to show-names
  ask turtles [
   ifelse label = ""
   [set label (word who " ")] 
    [set label ""]
  ]
end 

to setup
  ca
  crt Nodes
  set-default-shape turtles "circle"
  ask turtles [setxy random-xcor random-ycor ]
  ;ask patches [set pcolor white]
end 

to create-random-graph
  ask links [die]
  ask turtles [create-links-with n-of ((random Max_Connections) + 1) other turtles]
end 

to circle 
  layout-circle turtles Radius
end 

to radial
  layout-radial turtles links turtle T_Ref
end 

to radial2
  let m []
  ask turtles [
    let n []
    set n lput who n
    set n lput count(my-links) n
    set m lput n m]
  print (word "The array of connections is: " m)
  set m sort-by [last ?2 < last ?1] m
  print (word "The sorted array of connections is: " m)
  let t_max first(first(m))  ;Turtle with high degree
  let n_max last(first(m))   ;Highest degree
  let n_min last(last(m))    ;Lowest degree
  let r_s 2.0 / (n_max - n_min)
  foreach m [
   ask turtle (first(?)) [set size (0.2 + (last(?) * r_s))] 
  ]
  print (word "So the turtle with high degree is: " t_max)
  layout-radial turtles links turtle t_max
end