---daisyworld.nlogo

NETLOGO

;    This program is free software; you can redistribute it and/or modify
;    it under the terms of the GNU General Public License as published by
;    the Free Software Foundation; either version 2 of the License, or
;    (at your option) any later version.

;    This program is distributed in the hope that it will be useful,
;    but WITHOUT ANY WARRANTY; without even the implied warranty of
;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;    GNU General Public License for more details.

;    You should have received a copy of the GNU General Public License
;    along with this program; if not, write to the Free Software
;    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307

patches-own [
  temperature
  albedo
  white?
  black?
  free?
  ]
  
globals [
  time
  global-temperature
  num-blacks
  num-whites
  scenario-phase
  ]
  
to setup

 clear-all
 ask patches [
   set pcolor grey
   set free? true
   set black? false
   set white? false
   set albedo albedo-of-empty
   ]
   
 set global-temperature 0
 set time 0  
 if (scenario? = true) [
     set scenario-phase 1
     set solar-luminosity 0.6
     ]
 repeat (start-number-blacks) [
   seed-black-randomly
   ]
 repeat (start-number-whites) [
   seed-white-randomly
   ]

 ask patches [
   calc-temperature
   update-display 
   ]
   
   set global-temperature (mean values-from patches [temperature])
   set num-whites start-number-whites
   set num-blacks start-number-blacks
   
end


to go

  if (scenario? = true) [
      if (scenario-phase = 2) [
          set solar-luminosity (solar-luminosity - scenario-incrementor)
          if (solar-luminosity <= 0.3) [
              set scenario-phase 1
              stop go
              ]
          ]
      if (scenario-phase = 1) [
          set solar-luminosity (solar-luminosity + scenario-incrementor)
          if (solar-luminosity >= 2.3) [
              set scenario-phase 2
              ]
          ]
      ]
  diffuse temperature 1

  repeat (seed-number-blacks) [seed-black-randomly]
  repeat (seed-number-whites) [seed-white-randomly]

    ask patches [
    without-interruption [
       check-biology
       ]
    ]
  ask patches [     
    calc-temperature
    update-display
  ]

  set global-temperature (mean values-from patches [temperature])  
  
  set-current-plot "global temperature"
  plot global-temperature
  
  set-current-plot "luminosity"
  plot solar-luminosity
  
  set num-whites count patches with [white? = true]
  set num-blacks count patches with [black? = true]
  
  set-current-plot "Population"
  set-current-plot-pen "Black"
  plot num-blacks
  set-current-plot-pen "White"
  plot num-whites
   
  set time (time + 1)
end

to seed-black-randomly

 locals [x y counter]
 
 set counter 0
 
 ; setup a white daisy at a random empty position
 loop [
 set counter counter + 1
 set x ((random-int-or-float screen-size-x) - screen-edge-x)
 set y ((random-int-or-float screen-size-y) - screen-edge-y)
 if ((free?-of patch-at x y) = true) [
   set free?-of patch-at x y  false
   set black?-of patch-at x y true
   set white?-of patch-at x y false
   set albedo-of patch-at x y albedo-of-blacks
   stop
   ]
 if counter > 3 [stop]  
 ]   
  
end

to seed-white-randomly

 locals [x y counter]
 
 set counter 0
 ; setup a white daisy at a random empty position
 loop [
 set counter counter + 1
 set x ((random-int-or-float screen-size-x) - screen-edge-x)
 set y ((random-int-or-float screen-size-y) - screen-edge-y)
 if ((free?-of patch-at x y) = true) [
   set free?-of patch-at x y  false
   set black?-of patch-at x y false
   set white?-of patch-at x y true
   set albedo-of patch-at x y albedo-of-whites
   stop
   ]
  if counter > 3 [stop]    
 ]   
  
end

to check-biology

 locals [seed-threshold empty-space seeding-place]
 
 if (free? = false) [
    if ((random-int-or-float 1.0) < daisy-decay-rate) [
       set free? true
       set white? false
       set black? false
       set albedo albedo-of-empty
       ]
    set seed-threshold ((0.1457 * temperature) - (0.0032 * (temperature ^ 2)) - (0.6443))
    if ((random-int-or-float 1.0) < seed-threshold) [
       set empty-space neighbors with [(free? = true)]
       set seeding-place random-one-of empty-space
       if (seeding-place != nobody) [
           if (white? = true) [
              ask seeding-place [
                  set free? false
                  set white? true
                  set black? false
                  set albedo albedo-of-whites
                  ]
               ]
           if (black? = true) [
              ask seeding-place [
                  set free? false
                  set white? false
                  set black? true
                  set albedo albedo-of-blacks
                  ]
               ]
               
           ]
      ]
   ]

end

to calc-temperature

 locals [absorbed-luminosity local-heating]
 set absorbed-luminosity ((1 - albedo) * solar-luminosity)
 set local-heating 72.362 * LN(absorbed-luminosity) + 79.852
 set temperature ((temperature + local-heating) / 2)
    
end

to update-display

 ifelse (draw-temp-map? = true) [
   set pcolor scale-color red temperature -50 110
   ]
   [
   ifelse (free? = true) [set pcolor grey]
       [
       ifelse (black? = true) 
            [set pcolor black]      
            [set pcolor white]       
       ]
   ]

end

@#$#@#$#@
GRAPHICS-WINDOW
236
14
945
450
47
27
7.36
0
10
1
1
1

CC-WINDOW
11
613
224
674
Command Center

BUTTON
149
381
221
420
NIL
setup
NIL
1
T
OBSERVER
T

BUTTON
164
422
223
461
NIL
go
T
1
T
OBSERVER
T

SLIDER
16
160
221
193
albedo-of-whites
albedo-of-whites
0
1
0.75
0.01
1
NIL

SLIDER
15
198
220
231
albedo-of-blacks
albedo-of-blacks
0
1
0.25
0.01
1
NIL

SLIDER
17
122
221
155
albedo-of-empty
albedo-of-empty
0
1
0.5
0.01
1
NIL

SLIDER
14
236
220
269
start-number-blacks
start-number-blacks
0
100
5
1
1
NIL

SLIDER
14
272
220
305
start-number-whites
start-number-whites
0
100
5
1
1
NIL

SLIDER
14
308
220
341
seed-number-blacks
seed-number-blacks
0
100
1
1
1
NIL

SLIDER
14
343
220
376
seed-number-whites
seed-number-whites
0
100
1
1
1
NIL

SWITCH
15
427
158
460
draw-temp-map?
draw-temp-map?
1
1
-1000

MONITOR
89
510
223
559
NIL
global-temperature
3
1

SLIDER
19
42