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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。, p% c8 \/ \+ o) |' z6 _
netlogo自带的social science--traffic grid这一例子当中,
* K* K: T7 t) N* E8 {globals5 z4 a1 ~. |% L0 t, G, g6 p, ?
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' k" h0 }% {2 O, t grid-x-inc ;; the amount of patches in between two roads in the x direction
4 X D2 Z& \. j9 C% v# z grid-y-inc ;; the amount of patches in between two roads in the y direction9 G7 L2 J: {9 D, z/ [' W7 ^3 t
acceleration ;; the constant that controls how much a car speeds up or slows down by if
4 d- N- h/ |; b) P ;; it is to accelerate or decelerate0 Y) V4 E4 q/ E, b! E8 P
phase ;; keeps track of the phase
% I" K4 S+ Q6 x- x" u' x num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure$ e8 `2 q1 G) {- J* X
current-light ;; the currently selected light
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;; patch agentsets
; n- p0 B6 z4 p% v5 O intersections ;; agentset containing the patches that are intersections
: X' z' U1 }4 A. m0 _/ o roads ;; agentset containing the patches that are roads4 U, Y. v/ t5 Y9 I/ y# A; i% t0 ^
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turtles-own# v- Q' M! @; y! L; m% o9 V
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: R7 g" l; I7 C speed ;; the speed of the turtle) X* f2 x7 Y E# S7 \
up-car? ;; true if the turtle moves downwards and false if it moves to the right! E9 S) m" U# U9 A
wait-time ;; the amount of time since the last time a turtle has moved
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; X; s% ?: F5 L( E- u6 @( hpatches-own
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intersection? ;; true if the patch is at the intersection of two roads5 ~' Y" V! Z1 E& k, l3 f0 j
green-light-up? ;; true if the green light is above the intersection. otherwise, false.7 o) Z2 A$ z$ c/ l7 a
;; false for a non-intersection patches.
2 L. d: g9 X q. `* a% h my-row ;; the row of the intersection counting from the upper left corner of the# V, t/ h8 p9 |, n
;; world. -1 for non-intersection patches.
7 i- r3 b$ R$ s( k& \ my-column ;; the column of the intersection counting from the upper left corner of the8 \$ d6 e! \( o5 e5 L+ B B# d, T
;; world. -1 for non-intersection patches.( g$ K: L& D9 h( o
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
7 ?% J7 f$ w5 V( ] auto? ;; whether or not this intersection will switch automatically.8 @( N% V. F6 h0 h5 \( C( a- I) D
;; false for non-intersection patches.$ \& K ~$ t2 ^" t; S, Q0 E
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; P0 J6 ~8 g% |7 ?' [;;;;;;;;;;;;;;;;;;;;;;
" _+ m }6 ]3 `( w5 c! y;; Setup Procedures ;;' u& Q3 M8 e |9 R6 `
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4 B. r5 N5 c+ C) N; f4 ^;; Initialize the display by giving the global and patch variables initial values.( \& W# y7 Z- f8 G6 n0 c
;; Create num-cars of turtles if there are enough road patches for one turtle to
4 e" n6 d& [+ i/ l5 Y% u C;; be created per road patch. Set up the plots.6 d! s* [/ J6 j; h, U
to setup
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6 o" z, {* M+ e+ z setup-globals% \% Z _% f" K8 \
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;; First we ask the patches to draw themselves and set up a few variables
4 v" y8 D! E! J' E+ k$ S! i7 r setup-patches
: r$ q3 T/ j; X# a make-current one-of intersections
+ E3 g2 g4 x! \, w8 K label-current
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set-default-shape turtles "car"" E0 o2 y& W$ s2 S* R5 y8 j% R
9 U E3 a0 s4 ^ if (num-cars > count roads)1 D" ]' i$ t0 q/ m- n A
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8 z4 e Y* d1 V user-message (word "There are too many cars for the amount of "; G, [6 z6 s2 C7 p
"road. Either increase the amount of roads "! O/ y! L7 H0 I4 u7 Z
"by increasing the GRID-SIZE-X or "
8 B; W) T. E0 h9 Y% P1 D "GRID-SIZE-Y sliders, or decrease the ": }( U7 \9 q/ L7 z
"number of cars by lowering the NUMBER slider.\n"# Y) l# Z0 q9 }% d
"The setup has stopped.")
% f1 s' s2 A8 j* M stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color* H% ~$ Y, T- U$ P8 O1 Y* ]# b
crt num-cars
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setup-cars
S, n5 n1 n) i# w# ] set-car-color
9 c) p5 `" c# T. e! P& H record-data
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;; give the turtles an initial speed
& R* I+ N" _( o; w: W) I K# i ask turtles [ set-car-speed ]
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$ ?0 \% }0 h9 C1 ~0 Z) t6 t/ h g. P reset-ticks7 W! Q2 s( H2 q7 E
end1 ]1 p$ ?% @1 \
2 l: L5 O+ K0 F& ~. |% g1 [( h2 x;; Initialize the global variables to appropriate values' Q% [0 P. J7 e
to setup-globals- Z3 w# q1 t. f, j8 u4 }
set current-light nobody ;; just for now, since there are no lights yet$ |$ J$ ~: T) Y- f
set phase 0
8 x5 z- c4 k) ~; K7 u# J set num-cars-stopped 02 `+ Q8 e* G! S- l* k: t; l8 H
set grid-x-inc world-width / grid-size-x
; _& l2 o9 M0 Q7 a8 X9 v 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 boundary6 h4 r' R f1 `; l# x$ w
set acceleration 0.099+ E! M1 q2 [* ?2 G9 l
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,$ b! S6 j c! c( W2 A& {, ]
;; and initialize the traffic lights to one setting
4 b F+ N$ O7 w% ^8 r% zto setup-patches
2 U8 r3 a# @7 y0 ^3 m: W ;; initialize the patch-owned variables and color the patches to a base-color+ R3 H% Z0 m) N& H1 S' V; _2 R
ask patches+ y8 b$ v# r, F' G) x/ L. K$ h- J' X
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set intersection? false* {8 I# H- E" b$ [* E) [
set auto? false! U/ X5 ]* W- z+ n ^. h! \6 }/ r7 z
set green-light-up? true
" O4 ^( Z+ H3 F/ O2 _$ X set my-row -1
5 z) F3 w6 p1 o% y7 f3 n set my-column -1
' Y, D) B; m% C4 _; p set my-phase -1
, H! V$ i7 h7 L* _+ x0 o set pcolor brown + 3; N+ i! Q3 L+ w6 J
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;; initialize the global variables that hold patch agentsets2 j! a; R5 r2 n, Y
set roads patches with% }/ Q. ?" M; E1 }! G& ]0 Z
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or0 R; E7 i, D) y* X |" q# [
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]( q* A0 p( _; _! ?* h: f. ~) [
set intersections roads with0 N# F6 T P- O9 a+ F7 Z
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
7 C y; y( L& X6 Y# Z9 r) k (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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$ q& q+ Q# G% K4 m4 K) P6 {& z ask roads [ set pcolor white ]. _, c A% R* e' @ j, A6 E! n: c& b
setup-intersections
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其中定义道路的句子,如下所示,是什么意思啊?
6 A, I7 N( o% ]2 \/ j set roads patches with, G* F; H* x. z
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or1 c A7 ~. ^0 B; _ u9 Q
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 K- L- I+ y! X G/ o$ W( C* ]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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