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新手,在看netlogo自带的例子时,有几行程序看不懂,希望高手能够指点。4 v+ s+ D4 L8 X' E1 D
netlogo自带的social science--traffic grid这一例子当中,
6 W! p0 O0 r! c, E/ h+ B$ S5 Fglobals
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3 S& x0 j" k: W4 z grid-x-inc ;; the amount of patches in between two roads in the x direction1 J9 Z; Y8 E- c; j
grid-y-inc ;; the amount of patches in between two roads in the y direction3 a* `+ X+ @4 k8 h" c# L1 V. m9 C- A
acceleration ;; the constant that controls how much a car speeds up or slows down by if9 b# ?+ f6 ], t& F, x
;; it is to accelerate or decelerate
9 U0 {0 [5 v# ^- e phase ;; keeps track of the phase: K2 b, X$ K- L6 Z t
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure' Q! ^0 o; [. a1 q. e
current-light ;; the currently selected light
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;; patch agentsets
' P: K4 h9 ?; E [1 l. J intersections ;; agentset containing the patches that are intersections
" B* R4 e/ f) s, g. H3 W4 X roads ;; agentset containing the patches that are roads
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turtles-own# z- V) W5 Q5 e: B s& d( m4 k9 X
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speed ;; the speed of the turtle
: R5 A) R; @6 J1 P* C7 h. k up-car? ;; true if the turtle moves downwards and false if it moves to the right
) Y1 O5 a8 l" \: f1 T* c9 K9 A wait-time ;; the amount of time since the last time a turtle has moved. }: r2 i/ C# w, }
]
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patches-own
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' ]2 c; L0 l0 K intersection? ;; true if the patch is at the intersection of two roads
! v+ u: q- V p green-light-up? ;; true if the green light is above the intersection. otherwise, false.
0 S7 y# w- g& F+ @7 c ;; false for a non-intersection patches.
3 v/ P$ G; n% H2 ?5 ]) a1 O my-row ;; the row of the intersection counting from the upper left corner of the
; H8 P! H* c$ @' P2 z ;; world. -1 for non-intersection patches. x2 f" }- g& I& O
my-column ;; the column of the intersection counting from the upper left corner of the* {7 o# [2 L6 V& g) q$ e$ K8 a" b
;; world. -1 for non-intersection patches.$ T+ \+ x4 `! U& ?7 i9 Y
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
& x0 O1 E `5 v9 { auto? ;; whether or not this intersection will switch automatically.% L9 W7 L% d% T
;; false for non-intersection patches.
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; L- g+ p/ o! S' N: d;;;;;;;;;;;;;;;;;;;;;;7 T$ F5 F9 S. s# h% U! r
;; Setup Procedures ;;; l- ]* y, j( @. t
;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.
2 F. |( Q3 `1 g) ?( B;; Create num-cars of turtles if there are enough road patches for one turtle to
$ D! Q1 O) |. m1 I, C) k;; be created per road patch. Set up the plots.! l6 ?4 h( ?7 L5 J
to setup; q% Y5 a0 |9 l# c, _0 E
ca
" I1 k/ }+ `* t setup-globals
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;; First we ask the patches to draw themselves and set up a few variables6 z- ~8 ?: _9 ]2 G! R8 R2 d2 k- F
setup-patches0 x% N6 e' N( g) m3 A4 i6 h
make-current one-of intersections k8 N0 l1 P% ?! C3 I( w. b( m
label-current) A9 T- m) ^6 v+ n
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set-default-shape turtles "car"
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if (num-cars > count roads)3 u0 m( p+ k r8 I% f$ D
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user-message (word "There are too many cars for the amount of "
- j' v8 a, k, H "road. Either increase the amount of roads "; N; v( f! T: K# R+ ^; F, E
"by increasing the GRID-SIZE-X or "
* I& y+ H6 R; V m- @ "GRID-SIZE-Y sliders, or decrease the "
" j5 E" S# M" o; E1 N3 b; v+ P "number of cars by lowering the NUMBER slider.\n"
; K& C2 J) c1 G( F- T "The setup has stopped.")( k5 | ] V- Z; U" I4 ~
stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
3 p* x a! E, A6 A3 Z crt num-cars
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setup-cars5 ?' w. K! _7 P; t/ D
set-car-color
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; A+ D# V2 b/ o ;; give the turtles an initial speed* [- ~: e% g2 g% `- q0 I0 n- W
ask turtles [ set-car-speed ]
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( [8 v* W) `! z reset-ticks
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;; Initialize the global variables to appropriate values
" \# }9 w7 O: uto setup-globals
5 A2 b/ u' g7 u/ t; U2 } set current-light nobody ;; just for now, since there are no lights yet. U5 }$ U- N/ Z2 W, _$ {4 ]6 f
set phase 0+ C6 v* o+ X p- n! P
set num-cars-stopped 0
% P" g& ^3 w4 I+ a0 o5 Y: W6 [ set grid-x-inc world-width / grid-size-x
; r9 h4 D# o4 i8 S; d9 P6 R set grid-y-inc world-height / grid-size-y$ y) l/ L" k+ u' d0 P4 s
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
8 Q+ D% U$ s: J: n+ Y6 \; e4 w set acceleration 0.0990 I; o* @# m1 {6 d
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
1 t z0 A, d# L# G. t$ M$ k2 `+ b;; and initialize the traffic lights to one setting. |8 _" q, e( B8 ~$ S
to setup-patches+ F' ?' h* c I6 c
;; initialize the patch-owned variables and color the patches to a base-color f+ a- y/ R) B' ?. A( o/ L' B
ask patches
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set intersection? false
* T" @5 O/ g! Z: A5 q3 g' k$ G set auto? false1 p+ @9 v/ L' K; R. O4 C
set green-light-up? true
3 a( x/ f, z1 I3 s set my-row -13 _5 G& g+ N" l( `7 @1 G
set my-column -1* [( I/ v1 C5 s* M m
set my-phase -1
9 a( u& l, ?$ U, H set pcolor brown + 3' g6 k/ C0 |% m" i% I
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4 x% d! P7 I7 a- H/ n ;; initialize the global variables that hold patch agentsets, b: k3 T$ { N
set roads patches with
N/ `7 R5 V+ P- c v9 b( U [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
H& N. f4 d c (floor((pycor + max-pycor) mod grid-y-inc) = 0)]; C W# o# l& t/ c8 M$ P: c" Q% |
set intersections roads with
1 f! d' ?, E3 Z$ F [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and0 C& o' l7 y" ~- J, E8 s! P
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]; \" U8 A- y$ z
setup-intersections
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1 U4 F# u" f7 X$ {- b0 k其中定义道路的句子,如下所示,是什么意思啊?
: G$ c& [! r3 } set roads patches with
& o, {* l: c& J' [ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or- I. n3 e2 ]! c) K
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]* C. V# T( q$ }) Q
谁能帮我解释一下[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0)是什么意思吗? |
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