Lanchester Combat Model

breed[force-units force-unit]

force-units-own[
  force-range
  accuracy
]

globals [
  separated-forces?
  accuracy-deviation
  free-move
  battle-move
]

to setup-globals
  set separated-forces? false
  set accuracy-deviation 0
  set free-move 0
  set battle-move 0
end 

to startup
  set initial-blue-forces 2000
  set initial-red-forces 2050
  set blue-accuracy 1
  set red-accuracy 1
  set blue-range max-range + 1
  set red-range max-range + 1
  set blue-area-fire? false
  set red-area-fire? false
  setup
end 

to setup
  clear-all
  setup-globals
  setup-forces
  reset-ticks
end 

to go
  if battle-finished? [ stop ]
  go-forces
  tick
end 

to-report max-range
  report ceiling sqrt ( max-pxcor * max-pxcor + max-pycor * max-pycor )
end 

to setup-forces
  spwan-blue-forces
  spawn-red-forces
end 

to setup-accuracy [accuracy-mean accuracy-standard-deviation]
  ifelse accuracy-standard-deviation > 0 [
    set accuracy random-normal accuracy-mean accuracy-standard-deviation
  ] [
    set accuracy accuracy-mean
  ]
  set accuracy min list 1 accuracy
  set accuracy max list 0 accuracy
end 

to spwan-blue-forces
  create-force-units initial-blue-forces [
    set color blue
    ifelse separated-forces? [
      set xcor random-xcor
      set ycor (max-pycor / 2) + random-float (max-pycor / 2)
      if random 2 = 1 [ set ycor (- ycor) ]
    ] [
      setxy random-xcor random-ycor
    ]
    setup-accuracy blue-accuracy accuracy-deviation
    set force-range blue-range
  ]
end 

to spawn-red-forces
  create-force-units initial-red-forces [
    set color red
    ifelse separated-forces? [
      set xcor random-xcor
      set ycor (random-ycor / 2)
    ] [
      setxy random-xcor random-ycor
    ]
    setup-accuracy red-accuracy accuracy-deviation
    set force-range red-range
  ]
end 

to go-forces
  ask force-units [ force-unit-attack ]
end 

to-report hostile-force-units
  report force-units with [color != [color] of myself]
end 

to-report force-unit-select-target
  let target nobody
  let area-fire? ((color = blue and blue-area-fire?)
    or (color = red and red-area-fire?))
  ifelse area-fire? [
    let target-patch one-of patches
    if force-range < max-range [
      set target-patch one-of patches in-radius force-range
    ]
    ask target-patch [
      if any? force-units-here [ set target one-of force-units-here ]
    ]
  ] [
    let targets hostile-force-units
    if force-range < max-range [ set targets targets in-radius force-range ]
    set target min-one-of targets [distance myself]
  ]
  report target
end 

to force-unit-attack
  let target force-unit-select-target
  ifelse target != nobody [
    face target
    if random-float 1 < (accuracy ^ (distance target)) [ ask target [ die ] ]
    force-unit-move battle-move
  ] [
    force-unit-move free-move
  ]
end 

to force-unit-move [ steps ]
  if steps > 0 [
    if any? hostile-force-units [
      let target min-one-of hostile-force-units [distance myself]
      face target
    ]
    forward steps
  ]
end 

to-report battle-finished?
  report not any? turtles with [color = red] or not any? turtles with [color = blue]
end 

to scenario-one
  set initial-blue-forces 2000
  set initial-red-forces 2050
  set blue-accuracy 0.95
  set red-accuracy 0.9
  set blue-range max-range + 1
  set red-range max-range + 1
  setup
end 

to scenario-two
  set initial-blue-forces 1800
  set blue-accuracy 0.62
  set blue-range 5
  set initial-red-forces 2000
  set red-accuracy 0.6
  set red-range max-range + 1
  clear-all
  set separated-forces? true
  set accuracy-deviation 0.1
  set free-move 1
  set battle-move 0.25
  setup-forces
  reset-ticks
end