;;-------------------------------------------------------------------------------- ;; ;; robots.nlogo ;; ;; A program which simulates a robo moving around on a grid world. Each patch is ;; a square in the grid, and may contain an obstacle. The robot is trying to find ;; its way to a goal patch. ;; ;; Written by: Simon Parsons ;; October 2010 ;;-------------------------------------------------------------------------------- ;; ;; We have one breed and a few global variables breed [robots robot] globals [g-xcor g-ycor r-xcor r-ycor r-plan done nodes-on-agenda nodes-visited] ;;-------------------------------------------------------------------------------- ;; ;; Code to set up the environment ;; setup ;; ;; To setup we get rid of any existing robots, color the background, pick obstacle ;; locations and a goal, and then put the robot down in a random position to setup ask turtles [die] paint-patches generate-obstacles set-goal position-robot set r-plan [] set done false clear-plot set nodes-on-agenda 0 set nodes-visited 0 end ;; paint-patches to paint-patches ask patches [set pcolor green] end ;; generate-obstacles to generate-obstacles repeat obstacles [ask one-of patches [set pcolor black]] end ;; set-goal to set-goal ask one-of patches [ set pcolor red set g-xcor pxcor set g-ycor pycor ] end ;; position-robot to position-robot ;; setup the robot breed set-default-shape robots "robot" create-robots 1 [set color black] ;; place the robot ;; remember the initial location of the robot to allow us to reset set r-xcor free-x-cor set r-ycor free-y-cor ask robots [set xcor r-xcor] ask robots [set ycor r-ycor] ask robots [set heading 0] ;; make sure there isn't an obstacle at the robot's initial position ask patches [if ((pxcor = r-xcor) and (pycor = r-ycor)) [ set pcolor green ]] end ;; free-x-cor free-y-cor ;; ;; These are supposed to generate random locations that aren't obstacles. For ;; now they just report 0 or a random location (depending on the value of ;; robot-position, and we adjust the obstacles to avoid them. to-report free-x-cor if-else robot-position = "center"[ report 0 ] [ report random-pxcor ] end to-report free-y-cor if-else robot-position = "center"[ report 0 ] [ report random-pycor ] end ;; reset ;; ;; Reset allows you to return the robot to its initial position to run more ;; than once in the same environment. to reset ask robots [ set xcor r-xcor set ycor r-ycor ] set r-plan [] set done false repaint-space clear-plot set nodes-on-agenda 0 set nodes-visited 0 end ;; repaint-space ;; ;; In case we have been looking at the search, to repaint-space ask patches [ if (pcolor = blue) or (pcolor = yellow) or (pcolor = magenta)[ set pcolor green ] ] end ;;-------------------------------------------------------------------------------- ;; ;; ;; go ;; ;; The top level loop. Make the robot take a step forward, tick, and stop if the ;; robot is at the goal (which stops the clock). to go run-robot tick ask robots [at-goal-test] if done[ stop ] end ;; run-robot ;; ;; The high level call to make the robots move --- as long as you aren't at the ;; goal, make a move. to run-robot ask robots [ if-else not at-goal [ robot-move ] [ set color green ] ] end ;; robot-move ;; ;; The place where we plug in different ways to move the robot. The basic ;; mechanism is just to make a random move. to robot-move if-else movement = "random" [ robot-random-move ] [ robot-planned-move ] end ;; robot-random-move ;; ;; Pick a direction, randomly and with equal probability to robot-random-move let direction random 4 ;;show direction if direction = 0 [ move "north" ] if direction = 1 [ move "south" ] if direction = 2 [ move "east" ] if direction = 3 [ move "west" ] end ;; move ;; ;; You can move in a direction as long as there is no obstacle. to move [direction] ask robots [ if not obstacle direction patch-here[ step direction ] ] end ;; obstacle ;; ;; We spot an obstacle by identifying if there is a black patch in the ;; requisite direction, or if we are against the edge of the world. to-report obstacle[direction my-patch] let a-color green ;; First look at the color of the patch in the right direction, taking care of ;; the edges of the field, and repeat for all four directions. if direction = "north" [ if-else patch ([pxcor] of my-patch) (([pycor] of my-patch) + 1) = nobody [ set a-color black ] [ set a-color [pcolor] of patch ([pxcor] of my-patch) (([pycor] of my-patch) + 1) ] ] if direction = "south" [ if-else patch ([pxcor] of my-patch) (([pycor] of my-patch) - 1) = nobody [ set a-color black ] [ set a-color [pcolor] of patch ([pxcor] of my-patch) (([pycor] of my-patch) - 1) ] ] if direction = "east" [ if-else patch (([pxcor] of my-patch) + 1) ([pycor] of my-patch) = nobody [ set a-color black ] [ set a-color [pcolor] of patch (([pxcor] of my-patch) + 1) ([pycor] of my-patch) ] ] if direction = "west" [ if-else patch (([pxcor] of my-patch) - 1) ([pycor] of my-patch) = nobody [ set a-color black ] [ set a-color [pcolor] of patch (([pxcor] of my-patch) - 1) ([pycor] of my-patch) ] ] ;; Then report based on the color if-else a-color = black [ report true ] [ report false ] end ;; step ;; ;; Move in the requisite direction, making each step exactly one patch. to step [direction] if direction = "north" [ set ycor [pycor] of patch-at 0 1 ] if direction = "south" [ set ycor [pycor] of patch-at 0 -1 ] if direction = "east" [ set xcor [pxcor] of patch-at 1 0 ] if direction = "west" [ set xcor [pxcor] of patch-at -1 0 ] end ;; at-goal-test ;; ;; robot signals it has got to the goal so that we can stop the simulation to at-goal-test if is-goal patch-here [ set done true ] end ;; at-goal ;; ;; robot knows it has reached the goal to-report at-goal if-else is-goal patch-here [ report true ] [ report false ] end ;; is-goal ;; to-report is-goal [my-patch] let x-cor [pxcor] of my-patch let y-cor [pycor] of my-patch if-else ((x-cor = g-xcor) and (y-cor = g-ycor))[ report true ] [ report false ] end ;;--------------------------------------------------------------------------- ;; ;; Now, rather than moving, let's try searching. ;; robot-planned-move ;; ;; if r-plan is set, then we have found a plan, so we follow it. Otherwise we ;; look for a plan. to robot-planned-move if-else r-plan = [][ find-plan ] [ follow-plan ] end ;; follow-plan ;; ;; If we have a plan we follow it. A plan is a list of patches. To follow the plan ;; we take the first patch off the list and move to its x and y coordinates. Because ;; of the way the plan was assembled, this will always be a single step from where ;; we are. to follow-plan if r-plan != [][ let target first r-plan set r-plan but-first r-plan set xcor [pxcor] of target set ycor [pycor] of target if (show-path and not is-goal patch-here)[ ask patch-here [set pcolor magenta] ] ] end ;; find-plan ;; ;; Top-level function for plan finding. Delegates all the real work to get-plan, but ;; checks if no plan is found (if the agenda held by get-plan ever becomes empty) and ;; controls plan execution by only setting r-plan if we have a non-null plan. ;; ;; Also prints the plan out. to find-plan let plan (get-plan (list patch-here) [] (list (list patch-here))) if-else empty? plan [ show "failed" set done true ] [ show plan set r-plan plan ] end ;; get-plan ;; ;; does a simple breadth-first search through the navigable squares until ;; it finds the goal, and either returns the empty list, indicating it can't find ;; the goal, or a list of nodes that trace a path from the start point to the goal. ;; ;; The function is recursive, and calls itself for each new step in the plan. Somewhat ;; to my surprise, it only causes a stack overflow when we get to 30x30 worlds and we ;; are visiting 2500+ nodes. to-report get-plan[agenda visited-nodes plans] ;; if the agenda is empty, we have failed to find the goal if-else empty? agenda[ report [] ] [ ;; otherwise take the front node off the agenda and if it is the goal, we stop searchin let front first agenda if-else is-goal front [ report first plans ] [ ;; otherwise, remember we visited that node and find the nodes we can get to from it. set visited-nodes (lput front visited-nodes) ;;show visited-nodes let new-nodes (find-surrounding-nodes front) ;; we scour these nodes to remove ones we have visited before, or ones that are already ;; on the agenda. foreach visited-nodes [ set new-nodes remove ? new-nodes ] foreach agenda [ set new-nodes remove ? new-nodes ] ;; then, since these are new nodes, we remember how to get to them, and create ;; a new agenda. We discard the current front of the agenda, and the plan stub that ;; got us to that point (since it is now contained in a longer plan. set plans (append (but-first plans) (add-nodes-to-plan (first plans) new-nodes)) set agenda (append (but-first agenda) new-nodes) ;; plot the number of visited nodes, and color patches if we chose to do that and ;; set the values that get reported to the interface if show-agenda [ foreach agenda [ask ? [if (not is-goal self)[set pcolor blue]]] ] if-else show-visited [ foreach visited-nodes [ask ? [if (not is-goal self)[set pcolor yellow]]] ] [ ;; if we aren't showing the visited nodes, but we are showing the agenda, then we have ;; to set the visited nodes green so that they don't stay blue once they move off the ;; agenda if show-agenda [ foreach visited-nodes [ask ? [if (not is-goal self)[set pcolor green]]] ] ] set-current-plot-pen "visited nodes" ;; which pen we want to use next plot length visited-nodes set nodes-on-agenda length agenda set nodes-visited length visited-nodes report (get-plan agenda visited-nodes plans) ] ] end ;; find-surrounding-nodes ;; ;; given a patch and a list of patches, finds the patches north, south, east ;; and west of the given patch that are in the field and not obstacles, and ;; returns them to-report find-surrounding-nodes [my-patch] let node-list [] let new-patch nobody if not obstacle "north" my-patch [ ask my-patch [set new-patch patch-at 0 1] if new-patch != nobody [ set node-list lput new-patch node-list ] ] set new-patch 0 if not obstacle "south" my-patch [ ask my-patch [set new-patch patch-at 0 -1] if new-patch != nobody [ set node-list lput new-patch node-list ] ] set new-patch 0 if not obstacle "east" my-patch [ ask my-patch [set new-patch patch-at 1 0] if new-patch != nobody [ set node-list lput new-patch node-list ] ] set new-patch 0 if not obstacle "west" my-patch [ ask my-patch [set new-patch patch-at -1 0] if new-patch != nobody [ set node-list lput new-patch node-list ] ] report node-list end ;; add-nodes-to-plan ;; ;; Take each node in nodes in turn and add it to the end of the current plan to-report add-nodes-to-plan [plan nodes] let new-plans [] foreach nodes [ let new-plan lput ? plan set new-plans lput new-plan new-plans ] report new-plans end ;; remove-redundant-plans ;; ;; Given a node that we have already visited, and a set of plans, remove the plan to ;; take us to the node --- the node is redundant, and we don't want to keep plans that ;; won't be helpful. to-report remove-redundant-plans [node plans] let revised-plans [] foreach plans [ if (last ?) != node [ set revised-plans lput ? revised-plans ] ] report revised-plans end ;; append ;; ;; Join two lists together, tacking its second argument onto the end of the first ;; argument. ;; ;; I have it on good authority that this basic list handling functionality is in Netlogo ;; under another name, but I can't find it. to-report append [list1 list2] foreach list2 [ set list1 lput ? list1 ] report list1 end @#$#@#$#@ GRAPHICS-WINDOW 273 51 844 643 25 25 11.0 1 10 1 1 1 0 0 0 1 -25 25 -25 25 0 0 1 ticks BUTTON 29 39 95 72 NIL setup NIL 1 T OBSERVER NIL NIL NIL NIL SLIDER 28 80 223 113 obstacles obstacles 0 1000 750 1 1 NIL HORIZONTAL BUTTON 26 225 89 258 NIL go T 1 T OBSERVER NIL NIL NIL NIL MONITOR 26 267 83 312 NIL ticks\n 0 1 11 BUTTON 101 225 164 258 NIL reset NIL 1 T OBSERVER NIL NIL NIL NIL CHOOSER 28 118 222 163 movement movement "random" "breadth-first-search" 1 SWITCH 89 315 220 348 show-agenda show-agenda 0 1 -1000 SWITCH 89 358 220 391 show-visited show-visited 0 1 -1000 CHOOSER 28 169 222 214 robot-position robot-position "center" "random" 1 PLOT 25 410 185 530 visited nodes time nodes 0.0 10.0 0.0 10.0 true false PENS "visited nodes" 1.0 0 -16777216 true MONITOR 25 537 103 582 agenda nodes-on-agenda 0 1 11 MONITOR 107 537 185 582 visited nodes-visited 17 1 11 SWITCH 90 273 220 306 show-path show-path 0 1 -1000 @#$#@#$#@ WHAT IS IT? ----------- This section could give a general understanding of what the model is trying to show or explain. HOW IT WORKS ------------ This section could explain what rules the agents use to create the overall behavior of the model. HOW TO USE IT ------------- This section could explain how to use the model, including a description of each of the items in the interface tab. THINGS TO NOTICE ---------------- This section could give some ideas of things for the user to notice while running the model. THINGS TO TRY ------------- This section could give some ideas of things for the user to try to do (move sliders, switches, etc.) with the model. EXTENDING THE MODEL ------------------- This section could give some ideas of things to add or change in the procedures tab to make the model more complicated, detailed, accurate, etc. NETLOGO FEATURES ---------------- This section could point out any especially interesting or unusual features of NetLogo that the model makes use of, particularly in the Procedures tab. It might also point out places where workarounds were needed because of missing features. RELATED MODELS -------------- This section could give the names of models in the NetLogo Models Library or elsewhere which are of related interest. CREDITS AND REFERENCES ---------------------- This section could contain a reference to the model's URL on the web if it has one, as well as any other necessary credits or references. @#$#@#$#@ 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 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 robot true 0 Circle -7500403 false true 2 2 297 Line -7500403 true 150 0 150 105 robot2 false 0 Circle -7500403 true true 0 0 300 Circle -16777216 true false 30 30 240 Rectangle -7500403 true true 150 30 150 135 Rectangle -7500403 true true 135 30 160 138 sheep false 0 Rectangle -7500403 true true 151 225 180 285 Rectangle -7500403 true true 47 225 75 285 Rectangle -7500403 true true 15 75 210 225 Circle -7500403 true true 135 75 150 Circle -16777216 true false 165 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 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 4.1.1 @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ 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 @#$#@#$#@