---wolf_schaf.nlogo

NETLOGO

globals [ ticks
;;sheepStock
;;wolveStock
area
]

breeds [ sheep wolves ]
turtles-own [ energy ]
sheep-own [ grabbed? ]     ;; used to prevent two wolves from eating the same sheep
patches-own [ countdown ]

to setup
  ct
  cp
  set-current-plot "agent-populations"
  clear-plot
  set ticks 0
  ask patches [ set pcolor green ]


  set-default-shape sheep "sheep"
  create-custom-sheep initial-number-sheep  ;; create the sheep, then initialize their variables
  [
    set color white
    set label-color blue - 2
    set energy random (2 * sheep-gain-from-food)
    setxy random-float screen-size-x
          random-float screen-size-y
    set grabbed? false
    set size 1.5
  ]

  set-default-shape wolves "wolf"
  create-custom-wolves initial-number-wolves  ;; create the wolves, then initialize their variables
  [
    set color black
    set energy random (2 * wolf-gain-from-food)
    setxy random-float screen-size-x
          random-float screen-size-y
    set size 1.5
  ]

  display-labels

  do-plot
end

to setup-aggregate
  set-current-plot "populations"
  clear-plot
  ;; call procedure generated by aggregate modeler
  system-dynamics-setup
end

to step-aggregate
  ;; each agent tick is DT=1
  repeat ( 1 / dt ) [ system-dynamics-go ]
  system-dynamics-do-plot
end

to go
  ask sheep [
    move
    reproduce-sheep
    death
  ]
  ask wolves [
    move
    set energy energy - 1  ;; wolves lose energy as they move
    catch-sheep
    reproduce-wolves
    death
  ]
  do-plot  ;; plot populations
  every 0.5
    [ display-labels ]
  set ticks ticks + 1
  if not any? turtles [ stop ]
end

to move  ;; turtle procedure
  rt random-float 50 - random-float 50
  fd 1
end

to eat-grass  ;; sheep procedure
  ;; sheep eat grass, turn the patch brown
  if pcolor = green [
    set pcolor brown
    set energy energy + sheep-gain-from-food  ;; sheep gain energy by eating
  ]
end

to reproduce-sheep  ;; sheep procedure
  if random-float 100 < sheep-reproduce [  ;; throw "dice" to see if you will reproduce
    set energy (energy / 2)          ;; divide energy between parent and offspring
    hatch 1 [ rt random-float 360 fd 1 ]   ;; hatch an offspring and move it forward 1 step
  ]
end

to reproduce-wolves  ;; wolf procedure
  if random-float 100 < wolf-reproduce [  ;; throw "dice" to see if you will reproduce
    set energy (energy / 2 )  ;; divide energy between parent and offspring
    hatch 1 [ rt random-float 360 fd 1 ]  ;; hatch an offspring and move it forward 1 step
  ]
end

to catch-sheep  ;; wolf procedure
  let prey random-one-of (sheep-here             ;; grab a random sheep
                           with [not grabbed?]) ;; that no one else is grabbing
  if prey != nobody                             ;; did we get one?  if so,
    [ set grabbed?-of prey true                 ;; prevent other wolves from grabbing it
      ask prey [ die ]                          ;; kill it
      set energy energy + wolf-gain-from-food ]     ;; get energy from eating
end

to death  ;; turtle procedure
  ;; when energy dips below zero, die
  if energy < 0 [ die ]
end


to do-plot
  set-current-plot "agent-populations"
  set-current-plot-pen "sheep"
  plot count sheep
  set-current-plot-pen "wolves"
  plot count wolves
end

to display-labels
  ifelse show-energy?
  [

      ask wolves
      [ set label round energy ]
      ask sheep
      [ set label no-label ]
  ]
  [
    ask turtles
    [ set label no-label ]
  ]
end



; *** NetLogo Model Copyright Notice ***
;
; This model was created as part of the project: CONNECTED MATHEMATICS:
; MAKING SENSE OF COMPLEX PHENOMENA THROUGH BUILDING OBJECT-BASED PARALLEL
; MODELS (OBPML).  The project gratefully acknowledges the support of the
; National Science Foundation (Applications of Advanced Technologies
; Program) -- grant numbers RED #9552950 and REC #9632612.
;
; Copyright 2005 by Uri Wilensky. All rights reserved.
;
; Permission to use, modify or redistribute this model is hereby granted,
; provided that both of the following requirements are followed:
; a) this copyright notice is included.
; b) this model will not be redistributed for profit without permission
;    from Uri Wilensky.
; Contact Uri Wilensky for appropriate licenses for redistribution for
; profit.
;
; This model was converted to NetLogo as part of the project:
; PARTICIPATORY SIMULATIONS: NETWORK-BASED DESIGN FOR SYSTEMS LEARNING IN
; CLASSROOMS.  The project gratefully acknowledges the support of the
; National Science Foundation (REPP program) -- grant number REC #9814682.
;
; To refer to this model in academic publications, please use:
; Wilensky, U. (2005).  NetLogo Wolf Sheep Predation model.
; http://ccl.northwestern.edu/netlogo/models/WolfSheepPredationDocked.
; Center for Connected Learning and Computer-Based Modeling,
; Northwestern University, Evanston, IL.
;
; In other publications, please use:
; Copyright 2005 by Uri Wilensky.  All rights reserved.  See
; http://ccl.northwestern.edu/netlogo/models/WolfSheepPredationDocked
; for terms of use.
;
; *** End of NetLogo Model Copyright Notice ***

@#$#@#$#@
GRAPHICS-WINDOW
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20
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9.0
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1
1
1
0
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1
1

CC-WINDOW
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Command Center
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SLIDER
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177
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initial-number-sheep
initial-number-sheep
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1
1
NIL

SLIDER
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sheep-gain-from-food
sheep-gain-from-food
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NIL

SLIDER
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sheep-reproduce
sheep-reproduce
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20.0
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1
%

SLIDER
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initial-number-wolves
initial-number-wolves
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NIL

SLIDER
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wolf-gain-from-food
wolf-gain-from-food
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1
NIL

SLIDER
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wolf-reproduce
wolf-reproduce
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1.0
1
%

BUTTON
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setup
setup
NIL
1
T
OBSERVER
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NIL

BUTTON
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go
go
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T
OBSERVER
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NIL

PLOT
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agent-populations
time
pop.
0.0
100.0
0.0
100.0
true
true
PENS
"sheep" 1.0 0 -13345367 true
"wolves" 1.0 0 -2674135 true

MONITOR
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158
260
sheep
count sheep
3
1

MONITOR
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244
260
wolves
count wolves
3
1

MONITOR
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324
260
grass / 4
count patches with [ pcolor = green ] / 4
0
1

TEXTBOX
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99
Sheep settings

TEXTBOX
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98
Wolf settings

MONITOR
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260
time-ticks
ticks
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1

SWITCH
169
38
305
71
show-energy?
show-energy?
0
1
-1000

PLOT
759
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1068
469
populations
time
pop.
0.0
100.0
0.0
100.0
true
true
PENS
"wolfStock" 1.0 0 -2674135 true
"sheepStock" 1.0 0 -13345367 true

BUTTON
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system-dynamics-go
system-dynamics-go\nsystem-dynamics-do-plot
NIL
1
T
OBSERVER
T
NIL

MONITOR
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845
266
NIL
sheepStock
5
1

MONITOR
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938
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NIL
wolfStock
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1

BUTTON
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484
645
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Step Compare
go\nstep-aggregate
NIL
1
T
OBSERVER
T
N

BUTTON
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901
66
setup-aggregate
setup-aggregate
NIL
1
T
OBSERVER
T
NIL

SLIDER
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156
predationRate
predationRate
0
0.1
3.0E-4
1.0E-4
1
NIL

SLIDER
757
123
909
156
predatorEfficiency
predatorEfficiency
0
10
1.0
0.1
1
NIL

SLIDER
763
171
949
204
wolves-death-rate
wolves-death-rate
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1
0.15
0.01
1
NIL

BUTTON
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system-dynamics-go
system-dynamics-go\nsystem-dynamics-do-plot
T
1
T
OBSERVER
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NIL

MONITOR
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NIL