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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。
9 Q. [5 I8 r, r) l* Znetlogo自带的social science--traffic grid这一例子当中,
3 ?0 @$ V" c* z# `: P1 ]globals
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grid-x-inc ;; the amount of patches in between two roads in the x direction
7 b# G2 h" A0 f* D grid-y-inc ;; the amount of patches in between two roads in the y direction+ g, d8 F: m9 o2 o1 i; c
acceleration ;; the constant that controls how much a car speeds up or slows down by if$ S; w" ]$ H; N+ a* j
;; it is to accelerate or decelerate
+ U! Y: a' t, }3 ` phase ;; keeps track of the phase8 |$ u$ { C7 o" Q% N& E: H
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
8 k4 p7 c u5 T# I current-light ;; the currently selected light" L% Z }0 h" [+ Q7 P$ {# s
* [$ u. }: u2 I- D ;; patch agentsets4 B, g+ V1 l. @9 a
intersections ;; agentset containing the patches that are intersections9 c& ^; x5 R0 z- {" P' H! A
roads ;; agentset containing the patches that are roads( q3 D" r+ T- H! P, i2 D$ l+ h! B7 Y
]
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turtles-own
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' S& ?2 l# }5 d1 J- P: |- l2 e speed ;; the speed of the turtle0 U* t0 E- d' A
up-car? ;; true if the turtle moves downwards and false if it moves to the right- q' h0 n# Y$ e0 K" K& U
wait-time ;; the amount of time since the last time a turtle has moved
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! g. t9 T+ D1 {% J) Dpatches-own
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6 ?" s, d. d5 Y: F5 Z" u intersection? ;; true if the patch is at the intersection of two roads
6 P: }3 p: R9 M. p0 F6 ] green-light-up? ;; true if the green light is above the intersection. otherwise, false.
! G. _1 C# D/ U X ;; false for a non-intersection patches.
7 W, z& N' r) `6 w my-row ;; the row of the intersection counting from the upper left corner of the v/ z3 j; M5 l/ o$ u
;; world. -1 for non-intersection patches.
) h2 J( K; T* q* r my-column ;; the column of the intersection counting from the upper left corner of the- | D3 n0 t" [6 D
;; world. -1 for non-intersection patches.5 D+ u A+ L/ J3 \( `. d. L8 ?8 }
my-phase ;; the phase for the intersection. -1 for non-intersection patches.! F" X) e; q- f9 Q
auto? ;; whether or not this intersection will switch automatically.
6 m0 R, u7 V: r' S% W$ _# D, _' ^( | ;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;
- j3 U* `2 P! g. O' X;; Setup Procedures ;;7 T3 t3 m' m3 r0 I4 n3 M
;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.+ O1 d9 i+ t3 h3 C1 j% Z
;; Create num-cars of turtles if there are enough road patches for one turtle to
/ x$ N$ [+ p* g3 m* K;; be created per road patch. Set up the plots.
/ A. Y& T6 U) m) V$ ^to setup& P3 d R1 v: _6 D" m! r; `4 H" D
ca
5 H6 G5 h8 B" b1 d: R, y setup-globals' |4 X5 _& d# S% A. u) @
, }& w1 v( u- q. G0 w$ T ;; First we ask the patches to draw themselves and set up a few variables
$ e8 u& r# R r1 V1 |. P setup-patches
% y/ O3 o$ _. ?: v# b4 } make-current one-of intersections% \% r: g0 h6 I/ q: J! A
label-current
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set-default-shape turtles "car"5 _: P3 Q% S) f4 v% g( S u
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if (num-cars > count roads)! k' S, t3 J+ `9 ?. M
[
# {8 T. I6 e6 ]5 ` user-message (word "There are too many cars for the amount of "2 O/ v% r8 ~2 W$ B
"road. Either increase the amount of roads "9 i! `' P6 G) k
"by increasing the GRID-SIZE-X or "
2 Y# ^1 _$ q4 v0 r2 X- L "GRID-SIZE-Y sliders, or decrease the "
5 p q; G. ~; q1 n* g "number of cars by lowering the NUMBER slider.\n"- T0 r; o$ X: g2 l% ]6 L7 _9 y" r! W7 n
"The setup has stopped.")
: P. X p5 B7 k stop' \, u& E8 L2 Z! g: ]: K
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
9 T0 q2 R2 u+ F1 K8 e7 @) E crt num-cars% l& s) ]1 K; A6 O% m, W5 f
[
+ s9 }/ p- Y" Y. w, x setup-cars' j1 d$ ~2 [$ c. g
set-car-color
1 Y# ^$ j: ~/ y2 L' y record-data
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: _. n) N# z; j# e P$ {7 x" _ ;; give the turtles an initial speed, X& t" ]; q0 A2 C* O8 q6 Q
ask turtles [ set-car-speed ]
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reset-ticks
% _: b4 b- s' K7 V( Eend
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: @5 D! j$ b; j7 N) ?4 };; Initialize the global variables to appropriate values
4 J* l' p% Y" r- e2 d2 h2 G1 Xto setup-globals
7 J/ D e5 ?" S, m set current-light nobody ;; just for now, since there are no lights yet9 ]' Q% n# z; ?( H! s; t: K
set phase 0
. {0 x; M: y( G9 Y/ s set num-cars-stopped 0
! h: T2 J$ i j set grid-x-inc world-width / grid-size-x; u! A0 C1 R/ r: W7 c# Y, ?5 C
set grid-y-inc world-height / grid-size-y
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% y4 a! a" F% g& g- G2 V ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary3 g3 p) }) n5 p5 y t
set acceleration 0.0999 S% M/ l, Y! M5 C8 s& D
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,! h' |2 G# Z) u4 o
;; and initialize the traffic lights to one setting7 |* Y8 p2 l( _
to setup-patches( K( P+ T) a4 `/ `$ R
;; initialize the patch-owned variables and color the patches to a base-color
6 L4 D- J: r! B) E' B2 I4 a ask patches' o# L9 t2 _/ {: }
[
- I& Q$ B$ H5 E, R, k1 j5 Z. _ set intersection? false
1 L! v' k1 ?4 b. r, O set auto? false5 ]4 k! j8 M2 [+ j1 O+ u6 d( Q
set green-light-up? true7 v/ N" v% m5 [9 u8 I0 F
set my-row -1
, R2 C2 E' k! k6 k set my-column -1
L( P& i6 U* q5 H5 h" K/ t set my-phase -1
9 o, ~$ Z1 e6 u set pcolor brown + 3
1 E% O+ k: x0 p3 \, s ]
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; e* X+ B9 j1 ]: Y& }0 G9 k ;; initialize the global variables that hold patch agentsets* }4 ^. s% g2 D# i0 S
set roads patches with
: X- R" q2 `& W7 [ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or8 L3 A; v# |: {! M
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]0 G* m0 \% t( D
set intersections roads with
, j0 d8 z/ q5 ]0 J- ]7 _; z+ u [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
0 C5 D, m1 L7 j2 C y" |% J (floor((pycor + max-pycor) mod grid-y-inc) = 0)]$ U) \& H' m7 a% G- Z$ ^
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ask roads [ set pcolor white ]6 t, k' \2 s& s# S3 B& R5 m4 G
setup-intersections% m6 q0 w" T' R5 }2 y: `
end
4 f) Y3 S3 m& [' |1 @其中定义道路的句子,如下所示,是什么意思啊?0 Y7 U9 p; O* r+ }9 l
set roads patches with8 Z% i: C' u3 V+ l- _
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
5 ]# J: L5 y- K1 H* d& Y/ x (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
# U# U+ J B# k2 z; e% @: g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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