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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。- k7 H/ L q# K% z, \2 S
netlogo自带的social science--traffic grid这一例子当中,
) \" D, C" e3 T6 K E9 A) uglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction5 B& g8 T) C( W) v5 M% S; B
grid-y-inc ;; the amount of patches in between two roads in the y direction
) B' U# }& T* D! Z acceleration ;; the constant that controls how much a car speeds up or slows down by if
2 V- D2 a/ _6 J t ;; it is to accelerate or decelerate/ ~5 W2 K, g; a
phase ;; keeps track of the phase( ]9 `2 y2 e! Z" `$ u: B4 O
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
8 j: h1 V8 u3 D& m& n" z( a current-light ;; the currently selected light
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;; patch agentsets
$ N0 K1 Q( O5 Q: L9 S+ `8 Q& e intersections ;; agentset containing the patches that are intersections
o+ K5 ]2 \! C0 L2 }4 n roads ;; agentset containing the patches that are roads6 _4 u- D5 X" ^
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turtles-own
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, I. H" a) ~: H) U7 J speed ;; the speed of the turtle
$ C8 y5 B6 }2 Y6 ^% w up-car? ;; true if the turtle moves downwards and false if it moves to the right7 d: ], C8 t! y8 E2 G! Z5 y( {) ?
wait-time ;; the amount of time since the last time a turtle has moved# M- _9 L. V& I
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads
( y/ |( v+ l5 Z green-light-up? ;; true if the green light is above the intersection. otherwise, false.' }" x8 U+ U! v$ P3 e
;; false for a non-intersection patches.# V& w6 _ f% \6 J3 T! y( L
my-row ;; the row of the intersection counting from the upper left corner of the: v& E! W' C8 P1 O$ j
;; world. -1 for non-intersection patches.- x0 A3 p N" B9 l# o; }7 Q
my-column ;; the column of the intersection counting from the upper left corner of the
$ y( Y8 t2 w0 }) x) \. z ;; world. -1 for non-intersection patches.# i# |, a4 x) d" c, Y
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
, R! a1 r, C; t' k6 {) t auto? ;; whether or not this intersection will switch automatically.7 J3 T$ n" N$ `0 O! S& }
;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;
$ w" h; V- w0 a- N;; Setup Procedures ;;1 [6 r* J7 N) t; S7 n
;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.# W" c7 ^! s$ ]2 ^: r; d
;; Create num-cars of turtles if there are enough road patches for one turtle to" F5 [ v( x: Y8 D! Z! M1 f7 @
;; be created per road patch. Set up the plots.
0 n+ `& [. e' `: ^0 X' y2 rto setup
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3 @. S( b3 G/ [; Y! {! T setup-globals
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;; First we ask the patches to draw themselves and set up a few variables( ^" U# o* m. F' [
setup-patches
! Z6 k) L5 E& V G! _ make-current one-of intersections
# I- W/ \9 ?6 U/ \$ [ i9 @ label-current
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8 g6 F! v- I% R4 u4 R set-default-shape turtles "car"$ F) G O6 B& S; [ O% _
: y. ~+ V5 D6 A* v, B b0 V8 s- R if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "9 S; w2 F8 a. C( J! S. `3 m
"road. Either increase the amount of roads "
& N# Z! `9 V& ^7 W1 l0 n3 E) c "by increasing the GRID-SIZE-X or "
( g- ]' Z0 m$ x "GRID-SIZE-Y sliders, or decrease the "' e3 S, C% @# }' l; e
"number of cars by lowering the NUMBER slider.\n"
/ H' P" [6 S1 d$ D- C ]1 o "The setup has stopped.")
4 i" O k; j7 T6 l. X stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
$ }; z0 ]: y: L+ U' i' ]3 | crt num-cars8 m" C7 n* z) `$ ]) C" a8 d
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set-car-color
5 g9 ~8 K. {' y" a: R/ |0 r record-data
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;; give the turtles an initial speed
8 t2 M" g9 Q* r2 S$ I2 s t; w ask turtles [ set-car-speed ]0 l3 U5 \- g# p$ j
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reset-ticks
% D7 z$ I/ S, o# k1 uend
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8 Y, v) M7 y* d: a6 G;; Initialize the global variables to appropriate values
# W4 ?7 L5 O% D& ~$ P0 ?to setup-globals: a+ J' f8 U& W4 K
set current-light nobody ;; just for now, since there are no lights yet. ? L! i) _: D! T, k
set phase 0: O: p( |6 q, b5 h; g
set num-cars-stopped 0
: o" j n9 ~. b4 |8 H0 \- l X set grid-x-inc world-width / grid-size-x
; g5 V) s. c3 _, \; U) V* w D2 v set grid-y-inc world-height / grid-size-y
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& {6 ?; X& F- C( F, l' w ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary) r5 D; W: ?6 v
set acceleration 0.099
$ a# X- l+ \5 X' eend0 D0 m3 z: o4 K! h7 b6 c; g! f
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,5 l7 E8 Y! i9 e7 B2 Z
;; and initialize the traffic lights to one setting$ M; l7 T8 n: y) B) `
to setup-patches
0 N; O! d$ l, O6 f" u2 z c' S$ _ ;; initialize the patch-owned variables and color the patches to a base-color+ H+ p0 k ~# }$ m
ask patches: `4 G/ o/ }( B
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, i Y* F* i- m% i/ O6 x set intersection? false
5 @. q) G6 k [0 q set auto? false
9 ]) |! V3 g+ j. m2 r set green-light-up? true! ~% L8 A% D# D
set my-row -1
4 |- J3 o: O- D, n4 t4 d set my-column -1
& e4 a, w+ n% }- C3 d set my-phase -11 F4 u" y3 H) ?+ p7 a
set pcolor brown + 3/ N# c" B5 I; `5 {
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& t! q3 `; L' h, f, n/ X ;; initialize the global variables that hold patch agentsets+ ]2 {: V! d6 m0 C! L# q
set roads patches with
& g5 \ M$ i3 r6 I& L [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
$ g8 N, u+ H" A0 E5 K! }0 N (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
6 I; D% v( G, k9 g- r& F set intersections roads with
8 d. x* b* q0 B- B [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
& k' K, d# a: J; M0 `- U4 ^ (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]
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其中定义道路的句子,如下所示,是什么意思啊?
J2 ]9 F% E9 _6 X" I/ F3 x set roads patches with
( o% S/ O# h5 { [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
) O: U: k, B$ i; D) F( ^/ ^+ Q (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 G. ]! {, h" m; R! O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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