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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。) U% i" r7 [- G- U* N3 [/ d
netlogo自带的social science--traffic grid这一例子当中,
, a1 ]* A* E( f Q& r0 ~* Cglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction
* Y. j" J i' h& h% k2 Z grid-y-inc ;; the amount of patches in between two roads in the y direction! i7 d Y3 Y9 J
acceleration ;; the constant that controls how much a car speeds up or slows down by if0 c, f$ X# j/ A
;; it is to accelerate or decelerate1 i( B" E; A+ E, i* I G/ Y+ V# p
phase ;; keeps track of the phase/ [/ b- f0 e/ i- P6 n8 S0 y
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure& h: a) k& }+ o( X' S: u
current-light ;; the currently selected light# k' V6 I S3 n2 q
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;; patch agentsets
1 P5 M5 f! q# Z4 w& R- W* l1 x intersections ;; agentset containing the patches that are intersections
1 Y( c/ y# f. p! W roads ;; agentset containing the patches that are roads
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turtles-own
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speed ;; the speed of the turtle& o* }/ C" z# k. J* A- v
up-car? ;; true if the turtle moves downwards and false if it moves to the right
, O5 x* G: k7 G/ E wait-time ;; the amount of time since the last time a turtle has moved
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9 e4 F2 Q' f" Mpatches-own! H% [8 Q/ f4 a8 Q% r
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intersection? ;; true if the patch is at the intersection of two roads
9 x. C% C0 E: W/ r* z4 L green-light-up? ;; true if the green light is above the intersection. otherwise, false.
) D+ W! A+ x3 p" D& f) q, C ;; false for a non-intersection patches.
0 T8 t9 T2 y( O; z0 s" ? my-row ;; the row of the intersection counting from the upper left corner of the
% k9 d3 F# n$ O/ Y( Q ;; world. -1 for non-intersection patches. ^* O, k( b& h# `
my-column ;; the column of the intersection counting from the upper left corner of the/ r- L3 F( \* a; z O; q
;; world. -1 for non-intersection patches./ y" |" K1 B( h# i, x) y$ E
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
2 \, _ e' p; x; ~" w' s auto? ;; whether or not this intersection will switch automatically.# c: k5 `2 j% E% L- {( L: `8 O9 E
;; false for non-intersection patches.
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0 q5 O" h' O* O/ G H8 z8 h* y;;;;;;;;;;;;;;;;;;;;;;
6 O6 j$ k+ ?/ I;; Setup Procedures ;;
+ ], B, b. ?; g* u;;;;;;;;;;;;;;;;;;;;;;
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' z' P& H5 a, q5 w3 k3 C7 k$ D+ ^;; Initialize the display by giving the global and patch variables initial values.
* F+ g5 ^$ s" {1 n# ~3 }: d;; Create num-cars of turtles if there are enough road patches for one turtle to1 G! p- d/ G' u6 B7 l. n: V- M$ Q
;; be created per road patch. Set up the plots.) w% P- A. {) c; V0 c( ?. u
to setup
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setup-globals
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% N- T1 @# d7 U- e ;; First we ask the patches to draw themselves and set up a few variables9 E) v( M5 y1 T
setup-patches
4 N9 `0 `- \, F4 O6 _3 w make-current one-of intersections
$ `4 G1 ^; s5 l! C3 p label-current n+ T# _ \+ v8 B$ C* L
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set-default-shape turtles "car"' b1 ?7 ^ k/ c: a& G
/ @; R) L& h$ u4 ?- j+ m if (num-cars > count roads)1 _) t3 h" H2 @) `
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2 `# `" i& x5 z5 p7 W user-message (word "There are too many cars for the amount of "& @ a1 a3 n `2 B1 t
"road. Either increase the amount of roads "- k4 {$ A& Z+ B6 k, Q6 l
"by increasing the GRID-SIZE-X or "
5 [. ]) }7 n# g ~& ~ "GRID-SIZE-Y sliders, or decrease the "5 v4 R$ [' F& u6 h
"number of cars by lowering the NUMBER slider.\n"
+ m' O" r' m7 `/ M2 \ "The setup has stopped.")2 P9 h K% x7 n9 z0 I% G/ O6 l
stop: a# p9 ?, h, n+ f- @. }# g
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7 R2 ~! [3 h8 B ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color; ]( _. N! d; w" `
crt num-cars4 S5 P: o }7 S
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setup-cars7 m* _5 [3 x m7 x m5 c
set-car-color9 a& F. f$ x& I6 z9 B" d$ x4 a
record-data
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;; give the turtles an initial speed
- Z. Q) ~0 Y5 I8 [ ask turtles [ set-car-speed ]
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; J2 @1 Z# M# Y3 d8 b% y9 [. b reset-ticks
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+ i/ z$ Y) f W. f5 W;; Initialize the global variables to appropriate values
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( b3 m4 e& [- `- w set current-light nobody ;; just for now, since there are no lights yet$ I! Y3 h$ A5 i1 z
set phase 0" y" p- N* \& g$ z3 `. z& K
set num-cars-stopped 0" O/ ?& H. Z0 S8 ]
set grid-x-inc world-width / grid-size-x
, Y1 x( U" |( f: v: I6 r set grid-y-inc world-height / grid-size-y
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary9 ?* {) ?) H, ~6 {& J* a) D k5 h
set acceleration 0.099: l) y" q: x; u
end' X$ z2 ]0 k2 I- R$ v
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,! {5 q+ S8 i! a
;; and initialize the traffic lights to one setting% l0 `5 \! Z( Q" p
to setup-patches9 K1 K4 }/ r7 Z; F3 e4 Q
;; initialize the patch-owned variables and color the patches to a base-color
9 F7 [+ w/ b) D) Q! Q ask patches7 c2 t1 ~# _6 [3 T8 g
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6 W( @/ N( f1 n3 M2 ` set intersection? false, ^/ u8 m$ [- z6 Z( Z Z/ l
set auto? false
* B! Q1 Y# z# ?3 \* Q set green-light-up? true
% K& S4 k" `, E; i7 w- a set my-row -13 Y2 b8 `! {9 M2 N% o
set my-column -1
. L5 r; ?4 v6 p; c set my-phase -1
( b3 I: z- V3 ?3 y# T set pcolor brown + 3* k" i3 q& b. E- I$ }, t4 c7 j
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;; initialize the global variables that hold patch agentsets# u* m, Y' x/ m+ w' F/ I
set roads patches with
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(floor((pycor + max-pycor) mod grid-y-inc) = 0)]# i7 o) w0 {: m7 F
set intersections roads with; U9 N& l! m4 F1 J; p! ]
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and( F$ p( q! [* K+ \) E$ J
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]& }+ F: a3 R! r. l* Z6 H2 |# y
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ask roads [ set pcolor white ]& n4 L p2 u+ f, j+ G9 ~
setup-intersections
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1 e+ n8 \6 D& _. m5 ^0 l" o其中定义道路的句子,如下所示,是什么意思啊?6 ~! r- R" j. v
set roads patches with
8 ^6 e4 P6 s6 O1 u/ k8 ~ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or3 j1 i1 x* A$ y0 y% M
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
! ?# X8 z# j: x7 @. d- r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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