globals [ sheep-count-list wolf-count-list poison-activated? sheep-average wolf-average sheep-average-before wolf-average-before sheep-average-during wolf-average-during sheep-average-after wolf-average-after] breed [ sheep ] breed [ wolves ] turtles-own [ energy ] sheep-own [ grabbed? ] ;; used to prevent two wolves from eating the same sheep patches-own [ countdown ] to setup ca ask patches [ set pcolor green ] if grass? [ ;; indicates whether the grass switch is on ;; if it is true, then grass grows and the sheep eat it ;; if it false, then the sheep don't need to eat ask patches [ set countdown random grass-regrowth-time ;; initialize grass grow clocks randomly if (random 2) = 0 ;;half the patches start out with grass [ set pcolor brown ] ] ] ;; sets global for whether poison is on set poison-activated? false set-default-shape sheep "sheep" create-sheep initial-number-sheep ;; create the sheep, then initialize their variables [ set color white set size 1.5 ;; easier to see set label-color blue - 2 set energy random (2 * sheep-gain-from-food) setxy random-float world-width random-float world-height set grabbed? false ] set-default-shape wolves "wolf" create-wolves initial-number-wolves ;; create the wolves, then initialize their variables [ set color black set size 1.5 ;; easier to see set energy random (2 * wolf-gain-from-food) setxy random-float world-width random-float world-height ] ;; initialize globals set sheep-count-list [] set sheep-count-list lput initial-number-sheep sheep-count-list set wolf-count-list [] set wolf-count-list lput initial-number-wolves wolf-count-list set sheep-average-before 0 set wolf-average-before 0 set sheep-average-during 0 set wolf-average-during 0 set sheep-average-after 0 set wolf-average-after 0 display-labels ;; initialize plot settings set-current-plot "populations" set-plot-x-range 0 simulation-duration do-plot end to go ifelse (poison? and (ticks >= poison-begin) and (ticks < poison-begin + poison-duration)) [set poison-activated? true] [set poison-activated? false] ask sheep [ move if grass? [ set energy energy - 1 ;; deduct energy for sheep only if grass? switch is on eat-grass ] reproduce-sheep death if ((poison-activated? = true) and (pcolor = yellow)) [ die ] ] ask wolves [ move set energy energy - 1 ;; wolves lose energy as they move catch-sheep reproduce-wolves death if ((poison-activated? = true) and (pcolor = yellow)) [ die ] ] if grass? [ ask patches [ grow-grass ] ] ;; update globals set sheep-count-list lput count sheep sheep-count-list set wolf-count-list lput count wolves wolf-count-list ;; calculation for running averages ifelse (ticks < running-average) [set sheep-average mean sublist sheep-count-list 0 (ticks + 1) set wolf-average mean sublist wolf-count-list 0 (ticks + 1)] [set sheep-average mean sublist sheep-count-list (ticks - running-average) (ticks + 1) set wolf-average mean sublist wolf-count-list (ticks - running-average) (ticks + 1)] ;; calculation for averages before poison if (ticks = (poison-begin - 1)) [set sheep-average-before mean sheep-count-list set wolf-average-before mean wolf-count-list] ;; calculation for averages during poison if (ticks = (poison-begin + poison-duration - 1)) [set sheep-average-during mean sublist sheep-count-list poison-begin (ticks + 1) set wolf-average-during mean sublist wolf-count-list poison-begin (ticks + 1)] ;; calculation for averages after poison if (ticks >= (poison-begin + poison-duration)) [set sheep-average-after mean sublist sheep-count-list (poison-begin + poison-duration) (ticks + 1) set wolf-average-after mean sublist wolf-count-list (poison-begin + poison-duration) (ticks + 1)] do-plot ;; plot populations display-labels tick if ((not any? turtles) or (ticks >= simulation-duration)) [ 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 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 grow-grass ;; patch procedure ;; check if poison has been activated ;; if so, then see if patch should change to yellow if (ticks = poison-begin) [ if (random-float 100 < poison-abundance) [set pcolor yellow ] ] ;; check if poison has been deactivated ;; if so, then change patch to grass again if ((pcolor = yellow) and (poison-activated? = false)) [ set pcolor brown set countdown random grass-regrowth-time ] ;; countdown on brown patches, if reach 0, grow some grass if pcolor = brown [ ifelse countdown <= 0 [ set pcolor green set countdown grass-regrowth-time ] [ set countdown (countdown - 1) ] ] end to do-plot set-current-plot "populations" set-current-plot-pen "sheep" plot count sheep set-current-plot-pen "wolves" plot count wolves ;;if grass? [ ;; set-current-plot-pen "grass / 4" ;; plot count patches with [ pcolor = green ] / 4 ;; divide by four to keep it within similar ;; ;; range as wolf and sheep populations ;;] set-current-plot-pen "poison" ifelse ((ticks >= poison-begin) and (ticks < poison-begin + poison-duration)) [plot 500] [plot 0] set-current-plot "phase-plot" plotxy count sheep count wolves end to display-labels ifelse show-energy? [ ifelse grass? [ ask turtles [ set label round energy ] ] [ ask wolves [ set label round energy ] ask sheep [ set label "" ] ] ] [ ask turtles [ set label "" ] ] end ; *** Netlogo Model Copyright Notice *** ; Copyright 2007 by Kenneth Reisman and Michael Weisberg, ; based on Uri Wilensky (1998) NetLogo Wolf Sheep Predation model (see original copyright notice below). ; http://ccl.northwestern.edu/netlogo/models/WolfSheepPredation. ; 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, Kenneth Reisman, and Michael Weisberg. ; *** 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 1998 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. ; Converted from StarLogoT to NetLogo, 2000. Updated 2002. ; ; To refer to this model in academic publications, please use: ; Wilensky, U. (1998). NetLogo Wolf Sheep Predation model. ; http://ccl.northwestern.edu/netlogo/models/WolfSheepPredation. ; Center for Connected Learning and Computer-Based Modeling, ; Northwestern University, Evanston, IL. ; ; In other publications, please use: ; Copyright 1998 by Uri Wilensky. All rights reserved. See ; http://ccl.northwestern.edu/netlogo/models/WolfSheepPredation ; for terms of use. ; ; *** End of NetLogo Model Copyright Notice *** @#$#@#$#@ GRAPHICS-WINDOW 367 10 831 495 50 50 4.5 1 14 1 1 1 0 1 1 1 -50 50 -50 50 0 0 1 ticks CC-WINDOW 5 751 1012 846 Command Center 0 SLIDER 3 150 177 183 initial-number-sheep initial-number-sheep 0 1000 450 10 1 NIL HORIZONTAL SLIDER 3 187 177 220 sheep-gain-from-food sheep-gain-from-food 0.0 50.0 3 1.0 1 NIL HORIZONTAL SLIDER 3 222 177 255 sheep-reproduce sheep-reproduce 1.0 20.0 6 1.0 1 % HORIZONTAL SLIDER 182 149 347 182 initial-number-wolves initial-number-wolves 0 1000 600 10 1 NIL HORIZONTAL SLIDER 181 186 346 219 wolf-gain-from-food wolf-gain-from-food 0.0 100.0 20 1.0 1 NIL HORIZONTAL SLIDER 181 222 346 255 wolf-reproduce wolf-reproduce 0.0 20.0 5 1.0 1 % HORIZONTAL SWITCH 5 87 99 120 grass? grass? 0 1 -1000 SLIDER 116 87 347 120 grass-regrowth-time grass-regrowth-time 0 100 30 1 1 NIL HORIZONTAL BUTTON 8 28 77 61 setup setup NIL 1 T OBSERVER NIL NIL NIL NIL BUTTON 90 28 157 61 go go T 1 T OBSERVER NIL NIL NIL NIL PLOT 4 503 697 737 populations time pop. 0.0 100.0 0.0 100.0 true false PENS "sheep" 1.0 0 -13345367 true "wolves" 1.0 0 -2674135 true "grass / 4" 1.0 0 -10899396 true "poison" 1.0 0 -1184463 true MONITOR 91 262 162 307 sheep count sheep 3 1 11 MONITOR 166 262 248 307 wolves count wolves 3 1 11 MONITOR 252 262 338 307 grass / 4 count patches with [ pcolor = green ] / 4 0 1 11 TEXTBOX 8 130 148 149 Sheep settings 11 0.0 0 TEXTBOX 186 130 299 148 Wolf settings 11 0.0 0 TEXTBOX 9 68 161 86 Grass settings 11 0.0 0 MONITOR 9 262 87 307 time-ticks ticks 0 1 11 SWITCH 857 389 993 422 show-energy? show-energy? 1 1 -1000 MONITOR 2 442 174 487 Average number of sheep sheep-average\n 1 1 11 MONITOR 184 442 361 487 Average number of wolves wolf-average\n 1 1 11 TEXTBOX 14 324 164 342 Poison Settings\n 11 0.0 0 SLIDER 183 393 355 426 poison-abundance poison-abundance 0 10 1.5 0.1 1 NIL HORIZONTAL SLIDER 183 346 355 379 poison-begin poison-begin 0 5000 5000 50 1 NIL HORIZONTAL SLIDER 1 393 173 426 poison-duration poison-duration 0 2000 2000 50 1 NIL HORIZONTAL SWITCH 16 346 171 379 poison? poison? 0 1 -1000 SLIDER 854 434 1000 467 running-average running-average 0 1000 220 10 1 NIL HORIZONTAL MONITOR 845 17 997 62 NIL sheep-average-before 1 1 11 MONITOR 846 75 996 120 NIL wolf-average-before 1 1 11 MONITOR 847 135 997 180 NIL sheep-average-during 1 1 11 MONITOR 850 196 995 241 NIL wolf-average-during 1 1 11 MONITOR 850 262 998 307 NIL sheep-average-after 1 1 11 MONITOR 849 327 997 372 NIL wolf-average-after 1 1 11 SLIDER 174 30 341 63 simulation-duration simulation-duration 0 10000 6000 100 1 NIL HORIZONTAL PLOT 705 503 1003 737 phase-plot sheep population wolf population 0.0 10.0 0.0 10.0 true false PENS "default" 1.0 0 -16777216 true @#$#@#$#@ CREDITS AND REFERENCES ---------------------- Copyright 2007 by Kenneth Reisman and Michael Weisberg, based on Uri Wilensky (1998) NetLogo Wolf Sheep Predation model. http://ccl.northwestern.edu/netlogo/models/WolfSheepPredation. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL. 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, Kenneth Reisman, and Michael Weisberg. @#$#@#$#@ default true 0 Polygon -7500403 true true 150 5 40 250 150 205 260 250 airplane true 0 Polygon -7500403 true true 150 0 135 15 120 60 120 105 15 165 15 195 120 180 135 240 105 270 120 285 150 270 180 285 210 270 165 240 180 180 285 195 285 165 180 105 180 60 165 15 arrow true 0 Polygon -7500403 true true 150 0 0 150 105 150 105 293 195 293 195 150 300 150 box false 0 Polygon -7500403 true true 150 285 285 225 285 75 150 135 Polygon -7500403 true true 150 135 15 75 150 15 285 75 Polygon -7500403 true true 15 75 15 225 150 285 150 135 Line -16777216 false 150 285 150 135 Line -16777216 false 150 135 15 75 Line -16777216 false 150 135 285 75 bug true 0 Circle -7500403 true true 96 182 108 Circle -7500403 true true 110 127 80 Circle -7500403 true true 110 75 80 Line -7500403 true 150 100 80 30 Line -7500403 true 150 100 220 30 butterfly true 0 Polygon -7500403 true true 150 165 209 199 225 225 225 255 195 270 165 255 150 240 Polygon -7500403 true true 150 165 89 198 75 225 75 255 105 270 135 255 150 240 Polygon -7500403 true true 139 148 100 105 55 90 25 90 10 105 10 135 25 180 40 195 85 194 139 163 Polygon -7500403 true true 162 150 200 105 245 90 275 90 290 105 290 135 275 180 260 195 215 195 162 165 Polygon -16777216 true false 150 255 135 225 120 150 135 120 150 105 165 120 180 150 165 225 Circle -16777216 true false 135 90 30 Line -16777216 false 150 105 195 60 Line -16777216 false 150 105 105 60 car false 0 Polygon -7500403 true true 300 180 279 164 261 144 240 135 226 132 213 106 203 84 185 63 159 50 135 50 75 60 0 150 0 165 0 225 300 225 300 180 Circle -16777216 true false 180 180 90 Circle -16777216 true false 30 180 90 Polygon -16777216 true false 162 80 132 78 134 135 209 135 194 105 189 96 180 89 Circle -7500403 true true 47 195 58 Circle -7500403 true true 195 195 58 circle false 0 Circle -7500403 true true 0 0 300 circle 2 false 0 Circle -7500403 true true 0 0 300 Circle -16777216 true false 30 30 240 cow false 0 Polygon -7500403 true true 200 193 197 249 179 249 177 196 166 187 140 189 93 191 78 179 72 211 49 209 48 181 37 149 25 120 25 89 45 72 103 84 179 75 198 76 252 64 272 81 293 103 285 121 255 121 242 118 224 167 Polygon -7500403 true true 73 210 86 251 62 249 48 208 Polygon -7500403 true true 25 114 16 195 9 204 23 213 25 200 39 123 cylinder false 0 Circle -7500403 true true 0 0 300 dot false 0 Circle -7500403 true true 90 90 120 face happy false 0 Circle -7500403 true true 8 8 285 Circle -16777216 true false 60 75 60 Circle -16777216 true false 180 75 60 Polygon -16777216 true false 150 255 90 239 62 213 47 191 67 179 90 203 109 218 150 225 192 218 210 203 227 181 251 194 236 217 212 240 face neutral false 0 Circle -7500403 true true 8 7 285 Circle -16777216 true false 60 75 60 Circle -16777216 true false 180 75 60 Rectangle -16777216 true false 60 195 240 225 face sad false 0 Circle -7500403 true true 8 8 285 Circle -16777216 true false 60 75 60 Circle -16777216 true false 180 75 60 Polygon -16777216 true false 150 168 90 184 62 210 47 232 67 244 90 220 109 205 150 198 192 205 210 220 227 242 251 229 236 206 212 183 fish false 0 Polygon -1 true false 44 131 21 87 15 86 0 120 15 150 0 180 13 214 20 212 45 166 Polygon -1 true false 135 195 119 235 95 218 76 210 46 204 60 165 Polygon -1 true false 75 45 83 77 71 103 86 114 166 78 135 60 Polygon -7500403 true true 30 136 151 77 226 81 280 119 292 146 292 160 287 170 270 195 195 210 151 212 30 166 Circle -16777216 true false 215 106 30 flag false 0 Rectangle -7500403 true true 60 15 75 300 Polygon -7500403 true true 90 150 270 90 90 30 Line -7500403 true 75 135 90 135 Line -7500403 true 75 45 90 45 flower false 0 Polygon -10899396 true false 135 120 165 165 180 210 180 240 150 300 165 300 195 240 195 195 165 135 Circle -7500403 true true 85 132 38 Circle -7500403 true true 130 147 38 Circle -7500403 true true 192 85 38 Circle -7500403 true true 85 40 38 Circle -7500403 true true 177 40 38 Circle -7500403 true true 177 132 38 Circle -7500403 true true 70 85 38 Circle -7500403 true true 130 25 38 Circle -7500403 true true 96 51 108 Circle -16777216 true false 113 68 74 Polygon -10899396 true false 189 233 219 188 249 173 279 188 234 218 Polygon -10899396 true false 180 255 150 210 105 210 75 240 135 240 house false 0 Rectangle -7500403 true true 45 120 255 285 Rectangle -16777216 true false 120 210 180 285 Polygon -7500403 true true 15 120 150 15 285 120 Line -16777216 false 30 120 270 120 leaf false 0 Polygon -7500403 true true 150 210 135 195 120 210 60 210 30 195 60 180 60 165 15 135 30 120 15 105 40 104 45 90 60 90 90 105 105 120 120 120 105 60 120 60 135 30 150 15 165 30 180 60 195 60 180 120 195 120 210 105 240 90 255 90 263 104 285 105 270 120 285 135 240 165 240 180 270 195 240 210 180 210 165 195 Polygon -7500403 true true 135 195 135 240 120 255 105 255 105 285 135 285 165 240 165 195 line true 0 Line -7500403 true 150 0 150 300 line half true 0 Line -7500403 true 150 0 150 150 pentagon false 0 Polygon -7500403 true true 150 15 15 120 60 285 240 285 285 120 person false 0 Circle -7500403 true true 110 5 80 Polygon -7500403 true true 105 90 120 195 90 285 105 300 135 300 150 225 165 300 195 300 210 285 180 195 195 90 Rectangle -7500403 true true 127 79 172 94 Polygon -7500403 true true 195 90 240 150 225 180 165 105 Polygon -7500403 true true 105 90 60 150 75 180 135 105 plant false 0 Rectangle -7500403 true true 135 90 165 300 Polygon -7500403 true true 135 255 90 210 45 195 75 255 135 285 Polygon -7500403 true true 165 255 210 210 255 195 225 255 165 285 Polygon -7500403 true true 135 180 90 135 45 120 75 180 135 210 Polygon -7500403 true true 165 180 165 210 225 180 255 120 210 135 Polygon -7500403 true true 135 105 90 60 45 45 75 105 135 135 Polygon -7500403 true true 165 105 165 135 225 105 255 45 210 60 Polygon -7500403 true true 135 90 120 45 150 15 180 45 165 90 sheep false 0 Rectangle -16777216 true false 166 225 195 285 Rectangle -16777216 true false 62 225 90 285 Rectangle -7500403 true true 30 75 210 225 Circle -7500403 true true 135 75 150 Circle -16777216 true false 180 76 116 square false 0 Rectangle -7500403 true true 30 30 270 270 square 2 false 0 Rectangle -7500403 true true 30 30 270 270 Rectangle -16777216 true false 60 60 240 240 star false 0 Polygon -7500403 true true 151 1 185 108 298 108 207 175 242 282 151 216 59 282 94 175 3 108 116 108 target false 0 Circle -7500403 true true 0 0 300 Circle -16777216 true false 30 30 240 Circle -7500403 true true 60 60 180 Circle -16777216 true false 90 90 120 Circle -7500403 true true 120 120 60 tree false 0 Circle -7500403 true true 118 3 94 Rectangle -6459832 true false 120 195 180 300 Circle -7500403 true true 65 21 108 Circle -7500403 true true 116 41 127 Circle -7500403 true true 45 90 120 Circle -7500403 true true 104 74 152 triangle false 0 Polygon -7500403 true true 150 30 15 255 285 255 triangle 2 false 0 Polygon -7500403 true true 150 30 15 255 285 255 Polygon -16777216 true false 151 99 225 223 75 224 truck false 0 Rectangle -7500403 true true 4 45 195 187 Polygon -7500403 true true 296 193 296 150 259 134 244 104 208 104 207 194 Rectangle -1 true false 195 60 195 105 Polygon -16777216 true false 238 112 252 141 219 141 218 112 Circle -16777216 true false 234 174 42 Rectangle -7500403 true true 181 185 214 194 Circle -16777216 true false 144 174 42 Circle -16777216 true false 24 174 42 Circle -7500403 false true 24 174 42 Circle -7500403 false true 144 174 42 Circle -7500403 false true 234 174 42 turtle true 0 Polygon -10899396 true false 215 204 240 233 246 254 228 266 215 252 193 210 Polygon -10899396 true false 195 90 225 75 245 75 260 89 269 108 261 124 240 105 225 105 210 105 Polygon -10899396 true false 105 90 75 75 55 75 40 89 31 108 39 124 60 105 75 105 90 105 Polygon -10899396 true false 132 85 134 64 107 51 108 17 150 2 192 18 192 52 169 65 172 87 Polygon -10899396 true false 85 204 60 233 54 254 72 266 85 252 107 210 Polygon -7500403 true true 119 75 179 75 209 101 224 135 220 225 175 261 128 261 81 224 74 135 88 99 wheel false 0 Circle -7500403 true true 3 3 294 Circle -16777216 true false 30 30 240 Line -7500403 true 150 285 150 15 Line -7500403 true 15 150 285 150 Circle -7500403 true true 120 120 60 Line -7500403 true 216 40 79 269 Line -7500403 true 40 84 269 221 Line -7500403 true 40 216 269 79 Line -7500403 true 84 40 221 269 wolf false 0 Rectangle -7500403 true true 195 106 285 150 Rectangle -7500403 true true 195 90 255 105 Polygon -7500403 true true 240 90 217 44 196 90 Polygon -16777216 true false 234 89 218 59 203 89 Rectangle -1 true false 240 93 252 105 Rectangle -16777216 true false 242 96 249 104 Rectangle -16777216 true false 241 125 285 139 Polygon -1 true false 285 125 277 138 269 125 Polygon -1 true false 269 140 262 125 256 140 Rectangle -7500403 true true 45 120 195 195 Rectangle -7500403 true true 45 114 185 120 Rectangle -7500403 true true 165 195 180 270 Rectangle -7500403 true true 60 195 75 270 Polygon -7500403 true true 45 105 15 30 15 75 45 150 60 120 x false 0 Polygon -7500403 true true 270 75 225 30 30 225 75 270 Polygon -7500403 true true 30 75 75 30 270 225 225 270 @#$#@#$#@ NetLogo 4.0 @#$#@#$#@ setup set grass? true repeat 75 [ go ] @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ default 0.0 -0.2 0 0.0 1.0 0.0 1 1.0 0.0 0.2 0 0.0 1.0 link direction true 0 Line -7500403 true 150 150 90 180 Line -7500403 true 150 150 210 180 @#$#@#$#@