---lobster2applet.nlogo

NETLOGO

globals [
edge-patches 
clock 
]

breeds [homelobster huntlobster scent shelter]

patches-own [concentration]
scent-own [drop-size]

to setup
  ca
  set-default-shape homelobster "lobster" 
  create-homelobster 0   
    ask homelobster [set size 2]
    ask homelobster [set color red]
    ask homelobster [set heading 0]
  set-default-shape huntlobster "lobster" 
  create-huntlobster number   
    ask huntlobster [set size 2]
    ask huntlobster [set color blue]
  set-default-shape scent "circle"
  set-default-shape shelter "square"
  create-shelter 3
    ask shelter [set size 4]
    ask shelter [set color 35] 
    ask shelter [set heading (random 360) fd random screen-edge-x]
  ask huntlobster [set heading (random 360) fd random screen-edge-x]   
  set edge-patches (patches with [abs pxcor = screen-edge-x or
                                  abs pycor = screen-edge-y])
  set clock 0
end

to go 
  set clock (clock + 1)
  ask edge-patches
    [ set concentration 0 ] ;; prevent wrapping around screen edges
  scent-strategy
  move-scent
  ask patches [go-patches ]
  ifelse clock > 50 [ask huntlobster [track-plume]] 
  [ask huntlobster [fd 1 bounce rt random 90 - random 90]]
  plot-lobster
  if (count huntlobster = 0) [stop]
end

to scent-strategy
if strategy = "no scent" [move-scent]
if strategy = "home scent"  [ask homelobster [hatch-scent 3 [set size 0.1 
                                  set color blue 
                                  set drop-size 5]]]
if strategy = "time scent" [ask homelobster [hatch-scent 3 [set size 0.1 
                                  set color blue 
                                  set drop-size 5]]
 if clock > 50 [ask huntlobster [hatch-scent 3 [set size 0.1 
                                  set color blue 
                                  set drop-size 5]]]                                 
                                  ]

end


to move-scent 
  ask scent [ 
    flow-off-screen
    fd 1
    drop-chem
    set heading (90)   
    rt random (turbulence) - random (turbulence)  
  ] 
end

to flow-off-screen  ;; turtle (scent) procedure
  ; check: hitting left or right wall?
  if (abs pxcor-of patch-ahead 1 = screen-edge-x)
    ; if so, reflect heading around x axis
    [ die ]
  ; check: hitting top or bottom wall?
  if (abs pycor-of patch-ahead 1 = screen-edge-y)
    ; if so, reflect heading around y axis
    [ die ]
end

to drop-chem  ;; turtle (scent) procedure
;  if (clock > 0)
  set concentration (concentration + drop-size)
  set drop-size (drop-size * 0.8)
end

to go-patches  ;; patch procedure
  set concentration (concentration * (100 - evaporation-rate) / 100)  ;;slowly evaporate chemical
  update-display  ;; Refresh the Display
end

to update-display  ;; patch procedure
set pcolor scale-color green concentration 0.1 5  ;; scale color to show chemical concentration
end

to track-plume  ;; turtle (lobster) procedure
  ;; sniff left and right, and go where the strongest smell is
  fd 1 bounce rt random 90 - random 90
  let odor-ahead concentration-of patch-ahead 1
  let odor-right concentration-of patch-right-and-ahead 45 1
  let odor-left concentration-of patch-left-and-ahead 45 1
if (concentration > detection-level) [
if ((odor-right > odor-ahead) or (odor-left > odor-ahead))
    [ ifelse (odor-right > odor-left) [ rt 45 ] [ lt 45 ]]]
  if any? shelter-on neighbors [set breed homelobster set color red]
end

to bounce  ;; turtle (lobster) procedure
  ; check: hitting left or right wall?
  if (abs pxcor-of patch-ahead 1 = screen-edge-x)
    ; if so, reflect heading around x axis
    [ set heading (- heading) ]
  ; check: hitting top or bottom wall?
  if (abs pycor-of patch-ahead 1 = screen-edge-y)
    ; if so, reflect heading around y axis
    [ set heading (180 - heading) ]
end

to plot-lobster
set-current-plot "lobsters in shelter"
  set-current-plot-pen "# lobsters in shelter"
  plot count homelobster
  end
@#$#@#$#@
GRAPHICS-WINDOW
303
10
805
533
20
20
12.0
1
10
1
1
1
0

CC-WINDOW
5
547
814
642
Command Center

BUTTON
15
10
78
43
setup
setup
NIL
1
T
OBSERVER
T
NIL

BUTTON
106
12
169
45
go
go
T
1
T
OBSERVER
T
NIL

SLIDER
80
86
252
119
evaporation-rate
evaporation-rate
0
100
30
1
1
NIL

MONITOR
11
62
68
111
clock
clock
0
1

SLIDER
79
120
251
153
turbulence
turbulence
0
180
50
1
1
NIL

SLIDER
81
51
253
84
number
number
0
40
20
1
1
NIL

PLOT
13
304
261
523
lobsters in shelter
clock
# lobsters in shelter
0.0
40.0
0.0
10.0
true
false
PENS
"# lobsters in shelter" 1.0 0 -16777216 true

CHOOSER
3
198
141
243
strategy
strategy
"home scent" "time scent" "no scent"
0

TEXTBOX
147
196
297
286
"Home scent" is when lobsters emit scent in shelter. "Time scent" is when lobsters emit scent at a certain time. "No scent" means lobsters do not emit a scent.

SLIDER
78
157
250
190
detection-level
detection-level
0
10
0.2
0.1
1
NIL

@#$#@#$#@
WHAT IS IT?
-----------
This model investigates some of the factors that may be important for lobsters trying to locate a shelter.

Shelters and lobsters are placed randomly across the screen during the setup.

HOW IT WORKS
------------
Lobsters move about haphazardly for a short period (50) and then begin a search for shelter, either through a haphazard movement that brings them near a shelter or by detecting an odor emitted by lobsters occupying a shelter.  
Lobsters cannot leave the screen.

HOW TO USE IT
-------------
Shelters and lobsters are placed randomly acorss the screen during the setup.
Continue hitting the setup button until the shelters are spread out (not on top of each other).

You can manipulate if an attracting scent is produced when lobsters find a shelter, or if an attracting scent is released when a certain amount of time passes, or no scent is emitted.
You can manipulate the number of lobsters.
You can manipulate the evaporation rate such that the pheromone is long-lived (low evap)or short- lived (high evap).
You can manipulate the turbulence - high turbulence spreads the pheromone; low turbulence makes the plume more linear (laminar).
You can manipulate the minimum level of scent that a lobster can detect.
You could even manipulate the size of the field (screen size)

THINGS TO NOTICE
----------------
This section could give some ideas of things for the user to notice while running the model.


THINGS TO TRY
-------------
Note how long it takes lobsters to locate a shelter when there are just a few lobsters vs when there are lots of lobsters.

Note how long it takes lobsters to locate a shelter under the three strategies.