; add model procedures here turtles-own [energy] patches-own [food] globals [total-turtles] to setup ;; (for this model to work with NetLogo's new plotting features, ;; __clear-all-and-reset-ticks should be replaced with clear-all at ;; the beginning of your setup procedure and reset-ticks at the end ;; of the procedure.) ;; __clear-all-and-reset-ticks clear-all setup-food create-turtles init-num-of-turtles turtle-setup reset-ticks end to go turtles-move turtles-eat turtles-die turtles-reproduce grow-food do-plots if count turtles = 0 [stop] tick end to setup-food ask patches [ ifelse (random-float 1 <= initial-food-prob) [ set food 1 set pcolor green ] [ set food 0 set pcolor black ] ] end to grow-food ask patches [ if (random-float 1 <= food-grow-prob) [ set food 1 ] ifelse (food = 0) [set pcolor black] [set pcolor green] ] end to turtles-move ask turtles [ set heading (heading + random bearing-change - random bearing-change) forward 1 set energy energy - 0.1 ] end to turtles-eat ask turtles [ if ([food] of patch-here > 0) [ ask patch-here [set food 0] set energy energy + 1 ] ] end to turtles-die ask turtles [ if energy <= 0 [die] ] end to turtles-reproduce ask turtles [ if energy > reproduction-level [ set energy 0.5 * energy hatch 1 [lt 45 fd 1] ] ] end to turtle-setup ask turtles [ set size 2 set color white setxy (-1 * max-pxcor + random world-width) (-1 * max-pycor + random world-height) set energy random initial-energy ] end to do-plots set-current-plot "Num of Turtles" plot count turtles set total-turtles count turtles end @#$#@#$#@ GRAPHICS-WINDOW 21 107 452 559 30 30 6.902 1 10 1 1 1 0 1 1 1 -30 30 -30 30 0 0 1 ticks 30.0 BUTTON 21 8 85 42 NIL setup NIL 1 T OBSERVER NIL NIL NIL NIL 1 BUTTON 91 8 155 42 NIL go T 1 T OBSERVER NIL NIL NIL NIL 1 PLOT 526 111 726 261 Num of Turtles NIL NIL 0.0 20.0 0.0 20.0 true false "" "" PENS "default" 1.0 0 -16777216 true "" "" SLIDER 181 10 333 43 init-num-of-turtles init-num-of-turtles 50 1000 100 50 1 NIL HORIZONTAL SLIDER 371 10 496 43 bearing-change bearing-change 5 180 172 1 1 NIL HORIZONTAL MONITOR 21 56 97 101 NIL total-turtles 0 1 11 SLIDER 114 58 257 91 initial-energy initial-energy 0 40 11 1 1 NIL HORIZONTAL SLIDER 262 58 435 91 food-grow-prob food-grow-prob 0 0.1 1.0E-4 0.0001 1 NIL HORIZONTAL SLIDER 502 57 674 90 initial-food-prob initial-food-prob 0 1 0.19 0.01 1 NIL HORIZONTAL SLIDER 502 11 651 44 reproduction-level reproduction-level 0 20 15 1 1 NIL HORIZONTAL @#$#@#$#@ ## WHAT IS IT? This is an adaptation of the "Turtle Ecology" model from the Resnick "Turtles" book. ## HOW IT WORKS After the initial setup when food and turtles are randomly placed around the screen, the 'go' procedure runs forever. Each period the turtle moves, then eats, then some die, then some reproduce, then the food grows, and finally the plot is added to. ## HOW TO USE IT Set the values in the sliders, click on the Setup button and then click on the Go button to start (and then stop) the execution of the model. init-num-of-turtles: The number of turtles when the model starts executing. bearing-change: Each period the turtle resets its heading. If 'bearing-change' is 30, then it can change by 30 degrees to the left or 30 degrees to the right. Thus, the smaller this value, the more the agents will go in straight lines. reproduction: This is the minimum energy level that an agent must have for it to reproduce. initial-energy: This is the maximum energy value that an agent can have at the beginning of the simulation. The actual value is a random value between 0 and initial-energy. inverse-food-rate: The proportion of the patches that will grow back per period is 1/inverse-food-rate. inverse-food-setup: The proportion of the patches that start out with food is 1/inverse-food-setup. ## NETLOGO FEATURES This works somewhat differently than the StarLogo version described in the book. The book version uses "demons" while this version uses the "go" procedure to step through each of the different actions that a turtle does each period. ## CREDITS AND REFERENCES This model was developed at the MIT Media Lab. See Resnick, M. (1994) "Turtles, Termites and Traffic Jams: Explorations in Massively Parallel Microworlds." Cambridge, Ma: MIT Press, pp. 88-95. Scott A. Moore (samoore@umich.edu) of the University of Michigan Business School adapted this model to NetLogo. @#$#@#$#@ default true 0 Polygon -7500403 true true 150 5 40 250 150 205 260 250 ant true 0 Polygon -7500403 true true 136 61 129 46 144 30 119 45 124 60 114 82 97 37 132 10 93 36 111 84 127 105 172 105 189 84 208 35 171 11 202 35 204 37 186 82 177 60 180 44 159 32 170 44 165 60 Polygon -7500403 true true 150 95 135 103 139 117 125 149 137 180 135 196 150 204 166 195 161 180 174 150 158 116 164 102 Polygon -7500403 true true 149 186 128 197 114 232 134 270 149 282 166 270 185 232 171 195 149 186 Polygon -7500403 true true 225 66 230 107 159 122 161 127 234 111 236 106 Polygon -7500403 true true 78 58 99 116 139 123 137 128 95 119 Polygon -7500403 true true 48 103 90 147 129 147 130 151 86 151 Polygon -7500403 true true 65 224 92 171 134 160 135 164 95 175 Polygon -7500403 true true 235 222 210 170 163 162 161 166 208 174 Polygon -7500403 true true 249 107 211 147 168 147 168 150 213 150 arrow true 0 Polygon -7500403 true true 150 0 0 150 105 150 105 293 195 293 195 150 300 150 bee true 0 Polygon -1184463 true false 152 149 77 163 67 195 67 211 74 234 85 252 100 264 116 276 134 286 151 300 167 285 182 278 206 260 220 242 226 218 226 195 222 166 Polygon -16777216 true false 150 149 128 151 114 151 98 145 80 122 80 103 81 83 95 67 117 58 141 54 151 53 177 55 195 66 207 82 211 94 211 116 204 139 189 149 171 152 Polygon -7500403 true true 151 54 119 59 96 60 81 50 78 39 87 25 103 18 115 23 121 13 150 1 180 14 189 23 197 17 210 19 222 30 222 44 212 57 192 58 Polygon -16777216 true false 70 185 74 171 223 172 224 186 Polygon -16777216 true false 67 211 71 226 224 226 225 211 67 211 Polygon -16777216 true false 91 257 106 269 195 269 211 255 Line -1 false 144 100 70 87 Line -1 false 70 87 45 87 Line -1 false 45 86 26 97 Line -1 false 26 96 22 115 Line -1 false 22 115 25 130 Line -1 false 26 131 37 141 Line -1 false 37 141 55 144 Line -1 false 55 143 143 101 Line -1 false 141 100 227 138 Line -1 false 227 138 241 137 Line -1 false 241 137 249 129 Line -1 false 249 129 254 110 Line -1 false 253 108 248 97 Line -1 false 249 95 235 82 Line -1 false 235 82 144 100 bird1 false 0 Polygon -7500403 true true 2 6 2 39 270 298 297 298 299 271 187 160 279 75 276 22 100 67 31 0 bird2 false 0 Polygon -7500403 true true 2 4 33 4 298 270 298 298 272 298 155 184 117 289 61 295 61 105 0 43 boat1 false 0 Polygon -1 true false 63 162 90 207 223 207 290 162 Rectangle -6459832 true false 150 32 157 162 Polygon -13345367 true false 150 34 131 49 145 47 147 48 149 49 Polygon -7500403 true true 158 33 230 157 182 150 169 151 157 156 Polygon -7500403 true true 149 55 88 143 103 139 111 136 117 139 126 145 130 147 139 147 146 146 149 55 boat2 false 0 Polygon -1 true false 63 162 90 207 223 207 290 162 Rectangle -6459832 true false 150 32 157 162 Polygon -13345367 true false 150 34 131 49 145 47 147 48 149 49 Polygon -7500403 true true 157 54 175 79 174 96 185 102 178 112 194 124 196 131 190 139 192 146 211 151 216 154 157 154 Polygon -7500403 true true 150 74 146 91 139 99 143 114 141 123 137 126 131 129 132 139 142 136 126 142 119 147 148 147 boat3 false 0 Polygon -1 true false 63 162 90 207 223 207 290 162 Rectangle -6459832 true false 150 32 157 162 Polygon -13345367 true false 150 34 131 49 145 47 147 48 149 49 Polygon -7500403 true true 158 37 172 45 188 59 202 79 217 109 220 130 218 147 204 156 158 156 161 142 170 123 170 102 169 88 165 62 Polygon -7500403 true true 149 66 142 78 139 96 141 111 146 139 148 147 110 147 113 131 118 106 126 71 box true 0 Polygon -7500403 true true 45 255 255 255 255 45 45 45 butterfly1 true 0 Polygon -16777216 true false 151 76 138 91 138 284 150 296 162 286 162 91 Polygon -7500403 true true 164 106 184 79 205 61 236 48 259 53 279 86 287 119 289 158 278 177 256 182 164 181 Polygon -7500403 true true 136 110 119 82 110 71 85 61 59 48 36 56 17 88 6 115 2 147 15 178 134 178 Polygon -7500403 true true 46 181 28 227 50 255 77 273 112 283 135 274 135 180 Polygon -7500403 true true 165 185 254 184 272 224 255 251 236 267 191 283 164 276 Line -7500403 true 167 47 159 82 Line -7500403 true 136 47 145 81 Circle -7500403 true true 165 45 8 Circle -7500403 true true 134 45 6 Circle -7500403 true true 133 44 7 Circle -7500403 true true 133 43 8 circle false 0 Circle -7500403 true true 35 35 230 person false 0 Circle -7500403 true true 155 20 63 Rectangle -7500403 true true 158 79 217 164 Polygon -7500403 true true 158 81 110 129 131 143 158 109 165 110 Polygon -7500403 true true 216 83 267 123 248 143 215 107 Polygon -7500403 true true 167 163 145 234 183 234 183 163 Polygon -7500403 true true 195 163 195 233 227 233 206 159 sheep false 15 Rectangle -1 true true 90 75 270 225 Circle -1 true true 15 75 150 Rectangle -16777216 true false 81 225 134 286 Rectangle -16777216 true false 180 225 238 285 Circle -16777216 true false 1 88 92 spacecraft true 0 Polygon -7500403 true true 150 0 180 135 255 255 225 240 150 180 75 240 45 255 120 135 thin-arrow true 0 Polygon -7500403 true true 150 0 0 150 120 150 120 293 180 293 180 150 300 150 truck-down false 0 Polygon -7500403 true true 225 30 225 270 120 270 105 210 60 180 45 30 105 60 105 30 Polygon -8630108 true false 195 75 195 120 240 120 240 75 Polygon -8630108 true false 195 225 195 180 240 180 240 225 truck-left false 0 Polygon -7500403 true true 120 135 225 135 225 210 75 210 75 165 105 165 Polygon -8630108 true false 90 210 105 225 120 210 Polygon -8630108 true false 180 210 195 225 210 210 truck-right false 0 Polygon -7500403 true true 180 135 75 135 75 210 225 210 225 165 195 165 Polygon -8630108 true false 210 210 195 225 180 210 Polygon -8630108 true false 120 210 105 225 90 210 turtle true 0 Polygon -7500403 true true 138 75 162 75 165 105 225 105 225 142 195 135 195 187 225 195 225 225 195 217 195 202 105 202 105 217 75 225 75 195 105 187 105 135 75 142 75 105 135 105 wolf false 0 Rectangle -7500403 true true 15 105 105 165 Rectangle -7500403 true true 45 90 105 105 Polygon -7500403 true true 60 90 83 44 104 90 Polygon -16777216 true false 67 90 82 59 97 89 Rectangle -1 true false 48 93 59 105 Rectangle -16777216 true false 51 96 55 101 Rectangle -16777216 true false 0 121 15 135 Rectangle -16777216 true false 15 136 60 151 Polygon -1 true false 15 136 23 149 31 136 Polygon -1 true false 30 151 37 136 43 151 Rectangle -7500403 true true 105 120 263 195 Rectangle -7500403 true true 108 195 259 201 Rectangle -7500403 true true 114 201 252 210 Rectangle -7500403 true true 120 210 243 214 Rectangle -7500403 true true 115 114 255 120 Rectangle -7500403 true true 128 108 248 114 Rectangle -7500403 true true 150 105 225 108 Rectangle -7500403 true true 132 214 155 270 Rectangle -7500403 true true 110 260 132 270 Rectangle -7500403 true true 210 214 232 270 Rectangle -7500403 true true 189 260 210 270 Line -7500403 true 263 127 281 155 Line -7500403 true 281 155 281 192 wolf-left false 3 Polygon -6459832 true true 117 97 91 74 66 74 60 85 36 85 38 92 44 97 62 97 81 117 84 134 92 147 109 152 136 144 174 144 174 103 143 103 134 97 Polygon -6459832 true true 87 80 79 55 76 79 Polygon -6459832 true true 81 75 70 58 73 82 Polygon -6459832 true true 99 131 76 152 76 163 96 182 104 182 109 173 102 167 99 173 87 159 104 140 Polygon -6459832 true true 107 138 107 186 98 190 99 196 112 196 115 190 Polygon -6459832 true true 116 140 114 189 105 137 Rectangle -6459832 true true 109 150 114 192 Rectangle -6459832 true true 111 143 116 191 Polygon -6459832 true true 168 106 184 98 205 98 218 115 218 137 186 164 196 176 195 194 178 195 178 183 188 183 169 164 173 144 Polygon -6459832 true true 207 140 200 163 206 175 207 192 193 189 192 177 198 176 185 150 Polygon -6459832 true true 214 134 203 168 192 148 Polygon -6459832 true true 204 151 203 176 193 148 Polygon -6459832 true true 207 103 221 98 236 101 243 115 243 128 256 142 239 143 233 133 225 115 214 114 wolf-right false 3 Polygon -6459832 true true 170 127 200 93 231 93 237 103 262 103 261 113 253 119 231 119 215 143 213 160 208 173 189 187 169 190 154 190 126 180 106 171 72 171 73 126 122 126 144 123 159 123 Polygon -6459832 true true 201 99 214 69 215 99 Polygon -6459832 true true 207 98 223 71 220 101 Polygon -6459832 true true 184 172 189 234 203 238 203 246 187 247 180 239 171 180 Polygon -6459832 true true 197 174 204 220 218 224 219 234 201 232 195 225 179 179 Polygon -6459832 true true 78 167 95 187 95 208 79 220 92 234 98 235 100 249 81 246 76 241 61 212 65 195 52 170 45 150 44 128 55 121 69 121 81 135 Polygon -6459832 true true 48 143 58 141 Polygon -6459832 true true 46 136 68 137 Polygon -6459832 true true 45 129 35 142 37 159 53 192 47 210 62 238 80 237 Line -16777216 false 74 237 59 213 Line -16777216 false 59 213 59 212 Line -16777216 false 58 211 67 192 Polygon -6459832 true true 38 138 66 149 Polygon -6459832 true true 46 128 33 120 21 118 11 123 3 138 5 160 13 178 9 192 0 199 20 196 25 179 24 161 25 148 45 140 Polygon -6459832 true true 67 122 96 126 63 144 @#$#@#$#@ NetLogo 5.0RC2 @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ default 0.0 -0.2 0 1.0 0.0 0.0 1 1.0 0.0 0.2 0 1.0 0.0 link direction true 0 Line -7500403 true 150 150 90 180 Line -7500403 true 150 150 210 180 @#$#@#$#@ 0 @#$#@#$#@