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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。" S6 k1 K% x$ A* R g
netlogo自带的social science--traffic grid这一例子当中,: g# u. f& }. P( S" |
globals. }9 @/ H2 `6 H
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grid-x-inc ;; the amount of patches in between two roads in the x direction6 z/ Z9 ]. D1 ` F3 Y! W
grid-y-inc ;; the amount of patches in between two roads in the y direction
0 r, ~ S7 j6 M acceleration ;; the constant that controls how much a car speeds up or slows down by if
' I* N t) Q" ~. i$ N" l ;; it is to accelerate or decelerate
+ V- F7 K0 u! B' F phase ;; keeps track of the phase; z9 r# s" O& U7 a
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure8 s4 Y! A m8 `/ r" h- R2 b8 H
current-light ;; the currently selected light
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;; patch agentsets
3 M" V! v* l v8 A6 [" m% k5 O intersections ;; agentset containing the patches that are intersections
" t# v7 |! u4 ^7 @ roads ;; agentset containing the patches that are roads3 B4 h7 j5 m2 a! L4 D6 r
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turtles-own% v8 o& L# _- f! e- o
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speed ;; the speed of the turtle
0 g |: W! D3 p" a' g up-car? ;; true if the turtle moves downwards and false if it moves to the right
4 K: O3 a" s% V; a; @1 r wait-time ;; the amount of time since the last time a turtle has moved4 L$ h5 u6 S# g S8 S
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9 [4 L2 V% e, ]4 h+ J" ?patches-own
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intersection? ;; true if the patch is at the intersection of two roads" e" @* r& _: F4 e
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
) v' F Y; C; Y. ^- f3 \: r! O5 N6 Q6 x ;; false for a non-intersection patches.
3 x- E( M$ X- n8 Z) M2 h9 X my-row ;; the row of the intersection counting from the upper left corner of the
- J) s+ u; ]' ] ^* I: @ ;; world. -1 for non-intersection patches.( |; z: H3 ?3 B7 L V+ Z9 j9 d
my-column ;; the column of the intersection counting from the upper left corner of the% @) E5 s8 @6 ?" G1 _
;; world. -1 for non-intersection patches.
4 F ~/ i6 W/ J my-phase ;; the phase for the intersection. -1 for non-intersection patches.
6 w2 R. V* w3 S' l/ L auto? ;; whether or not this intersection will switch automatically.
- ~2 w' g2 J' b; T0 J ;; false for non-intersection patches.
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) k* U. P' v [ ]% V;;;;;;;;;;;;;;;;;;;;;;
: o% \7 n8 w# i. O$ U;; Setup Procedures ;;4 ^! |1 q4 o* P. E9 w
;;;;;;;;;;;;;;;;;;;;;;! J* Z- l: h+ V- U6 k
" m& k/ s" V. G" Z+ Q;; Initialize the display by giving the global and patch variables initial values. K; ~+ R2 r( E L% D; D' p- `7 A
;; Create num-cars of turtles if there are enough road patches for one turtle to
3 n: \: _4 v" W4 L- f# g% W9 Y;; be created per road patch. Set up the plots.
& J1 Z+ x, s Z, Jto setup
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* X" w& E: w" R& j) ` setup-globals+ I9 l+ a( P2 ?& M2 l, U9 T* B
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;; First we ask the patches to draw themselves and set up a few variables
: `5 r7 \7 B- T9 N setup-patches
, q1 n/ [! j) h make-current one-of intersections- J1 Y8 ]( @/ p& T7 N' D2 ~8 ^
label-current5 B5 O& I( B$ f" t8 P) T) L9 |; h
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set-default-shape turtles "car"
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if (num-cars > count roads)8 O+ x2 @+ ~/ V0 w9 Y
[
2 Y) l& z0 `0 o- v N& z) m user-message (word "There are too many cars for the amount of "! H4 t' a5 D6 Z' U1 T
"road. Either increase the amount of roads "# |* \2 V. b; H0 a0 |9 N
"by increasing the GRID-SIZE-X or "
% `2 N) p! H- Y- w* m- d) Y. v "GRID-SIZE-Y sliders, or decrease the "
R2 |3 ^) y3 j& {3 e+ T P" o "number of cars by lowering the NUMBER slider.\n"
$ u2 r7 C) N/ A$ D "The setup has stopped.")
+ g! a; X0 u& Z6 c5 y a; a stop6 G2 ~8 _+ \& a+ c/ u- P6 Y
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color/ b& z/ S8 U: i: V
crt num-cars
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setup-cars' C% F' N Y) G, P1 \; K
set-car-color+ V/ W) g% T: z
record-data
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;; give the turtles an initial speed1 W$ g; z/ a) Q6 E' Y, {' r. l
ask turtles [ set-car-speed ]
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reset-ticks& x% [. @4 d d) Q& }
end
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7 L' A8 t' d4 E3 y;; Initialize the global variables to appropriate values
% R& \6 |, o3 @+ M2 ^to setup-globals
" T! E) I# C5 B5 r, l) z set current-light nobody ;; just for now, since there are no lights yet, Z0 [* E5 _9 o
set phase 04 s7 {4 O1 j$ I8 n7 v' c
set num-cars-stopped 00 B: S. X; x* y$ k
set grid-x-inc world-width / grid-size-x- }. I) ^: Q0 E* W
set grid-y-inc world-height / grid-size-y
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7 N8 b f: G1 M2 O( o ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary3 H, R; x) f0 p/ }% b" X' q, M
set acceleration 0.099
$ m) Z- {" Y0 X# G. }8 uend4 T5 ?/ l1 |, v* |
( n4 B8 [1 ?* p2 w) v; Y;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
/ ~, b( ?* g( w& U8 u2 n;; and initialize the traffic lights to one setting
) J: {' I: `2 h/ x0 dto setup-patches
/ d& ?) }) O* O, c1 h- S ;; initialize the patch-owned variables and color the patches to a base-color- ]% v3 | A7 Y# c3 V9 {1 T
ask patches' G" z$ |" j' m6 V
[
2 |0 ~! g$ k! y set intersection? false
3 N7 O- o5 V0 ^: y7 `" n3 G1 o set auto? false! Q) P/ e6 Y# X8 S
set green-light-up? true
1 Z% Y* k$ P/ X( h7 `+ Q$ Q& D) D6 Y set my-row -19 d' c2 t3 p7 f0 e
set my-column -1
( a6 @8 N _- \0 l4 c set my-phase -1; V) Y! T, i* [4 u/ E
set pcolor brown + 31 x5 k; B z Z1 G/ W* N! h
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; x& s; G h' H/ N0 { ;; initialize the global variables that hold patch agentsets
! T' @* ` V; _% r9 k: K+ y set roads patches with
0 W R. Q' v/ D/ O2 q [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or6 A% Y7 `" }! L9 J* \" Y
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]2 y, ^% e( { \/ c1 l3 A) {
set intersections roads with! F: w: m& b1 B) e: A$ o$ T) t
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
7 z/ ~8 z4 P1 U4 W8 b0 A/ m/ B$ ` (floor((pycor + max-pycor) mod grid-y-inc) = 0)]6 {2 K9 r9 O" I5 ^) l+ t4 y) p
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ask roads [ set pcolor white ]
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( i! D. E! k/ p' _# E' L4 bend
7 s* R# G" b- I) N9 l& w, |- [其中定义道路的句子,如下所示,是什么意思啊?
, Q0 k1 q! F0 C, p2 E set roads patches with W& G0 K$ D1 S/ P
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
8 M& X# V$ p. Q: o$ G, G7 ` (floor((pycor + max-pycor) mod grid-y-inc) = 0)]1 B, ` Q4 L$ _( h$ e
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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