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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。
+ `/ \; [6 R& n& A" ?' \$ y# tnetlogo自带的social science--traffic grid这一例子当中,$ J, A8 ]" P5 A) e _- p2 g
globals7 q; t5 v' I e1 h
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grid-x-inc ;; the amount of patches in between two roads in the x direction, @* u: a* U/ y; Y3 P
grid-y-inc ;; the amount of patches in between two roads in the y direction2 `) l2 o) g0 X( K! g" C3 ^$ K. g
acceleration ;; the constant that controls how much a car speeds up or slows down by if
/ l, t% R% G% E/ n ;; it is to accelerate or decelerate/ |5 W9 }- q6 \9 n) K$ a( m
phase ;; keeps track of the phase
8 w! k: {( E/ y- q) ] num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure+ \0 T9 T9 G, q6 Q5 p1 p' E
current-light ;; the currently selected light3 o* I5 X9 f( N: b# d$ @7 D
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;; patch agentsets
. w$ q% ~$ C' q0 F, I intersections ;; agentset containing the patches that are intersections5 [% s+ p% ]& t. }2 a
roads ;; agentset containing the patches that are roads
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turtles-own* j/ V- I! f* Q8 \/ t& a
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speed ;; the speed of the turtle0 a! P( @' o' r& f* m3 I
up-car? ;; true if the turtle moves downwards and false if it moves to the right
3 x4 \1 O0 b+ M% V' U wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads5 w; W. y: Y- \7 s0 \9 c8 J" S
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
2 r6 z6 g3 u, S* U6 P ;; false for a non-intersection patches.. w+ c! Y- [( U7 |. z
my-row ;; the row of the intersection counting from the upper left corner of the7 X1 y. x4 F: P. v
;; world. -1 for non-intersection patches.
9 ?% `7 G$ i7 n1 l my-column ;; the column of the intersection counting from the upper left corner of the
" K2 X$ V* V. d+ T. Y3 n ;; world. -1 for non-intersection patches.
4 f# s8 ?$ u8 ?8 Q my-phase ;; the phase for the intersection. -1 for non-intersection patches.
! F# o8 G" _( a# U& W2 C auto? ;; whether or not this intersection will switch automatically.0 T; f! j2 `0 F
;; false for non-intersection patches.: }0 q$ S4 d/ k* a$ `+ _6 m
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;;;;;;;;;;;;;;;;;;;;;;& ~ x+ ?( Q# U* h f& @9 Z6 l
;; Setup Procedures ;;5 W( o1 Z! Y6 R# x
;;;;;;;;;;;;;;;;;;;;;;5 ` g' I+ G. I2 v5 G" I
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;; Initialize the display by giving the global and patch variables initial values.
2 J1 f% q) v- @;; Create num-cars of turtles if there are enough road patches for one turtle to
- V1 P! H9 y% p# K2 {, O3 };; be created per road patch. Set up the plots.
! i1 |# l" D* A+ G2 D; A5 K- nto setup
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setup-globals& \1 j' X& \* `
7 _! ]$ U- z1 C# R7 {9 u7 _2 J3 t ;; First we ask the patches to draw themselves and set up a few variables. [1 E* @! O% @& _/ H( V/ h
setup-patches) y$ p8 z4 N2 R4 Y! s5 C
make-current one-of intersections
: ?% R; [3 I7 l- W label-current
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, ~- m& R# f: D# N7 N set-default-shape turtles "car"
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if (num-cars > count roads)( Y1 ~# L8 ~* v2 y! a n
[
# b% t4 X5 @! [$ F% s& D user-message (word "There are too many cars for the amount of "# O1 T1 q" K X$ ]
"road. Either increase the amount of roads "' `% @6 W/ ]" z# B
"by increasing the GRID-SIZE-X or "
5 v5 D& c& r$ l. x! j "GRID-SIZE-Y sliders, or decrease the "
, {, `% E( w3 U/ z- t# d7 d- u "number of cars by lowering the NUMBER slider.\n"
8 s+ P: K1 _- @/ ~. M- Z6 ?) s "The setup has stopped.")
. R1 w6 r, @' U, Y% v8 s( d3 n stop
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+ }- o0 K9 R) F) f- A, m) D ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color7 o" r" _$ V; j" P( {) P
crt num-cars1 W+ l6 O/ k& }2 K3 t5 F, l. x6 r2 r
[
7 g, F+ Y- H; k setup-cars# s/ q' }4 h. o2 H9 @; @
set-car-color) ~ e& O0 p4 J! X2 c; p! C w
record-data
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# A$ e8 K+ ?( J" Y; P ;; give the turtles an initial speed
+ \& o" @6 e! g, t ^5 j& g ask turtles [ set-car-speed ]3 y! [+ z. L$ F+ Q _9 t
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reset-ticks
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;; Initialize the global variables to appropriate values8 a/ T: t7 h+ H5 M# c
to setup-globals5 T0 `* ~( c! z. ~/ E$ U9 q+ ^0 H
set current-light nobody ;; just for now, since there are no lights yet; |; _9 P% S& S! E: n7 y
set phase 0
+ l; o% G- [ @; [: Z, K% ] set num-cars-stopped 0
3 U0 U- H% a3 f. s5 U& W set grid-x-inc world-width / grid-size-x
. K% g% a/ \1 S' |2 \; w 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 boundary
3 x% }/ s0 p# ~# m# }& V+ r. l set acceleration 0.099
3 u' ^& H) Y) M( s+ k! [end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,7 x# |1 w7 V& \$ Q6 ^) e
;; and initialize the traffic lights to one setting8 t# B5 }( w8 i* c; u0 g, R
to setup-patches+ C& k0 i. ~' p% R" _
;; initialize the patch-owned variables and color the patches to a base-color
9 h" t, C' m6 ]5 }! S. f, ~1 } ask patches0 k" o7 }- R# |1 T& H4 I
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set intersection? false0 H' l$ L/ k1 T$ u5 X
set auto? false
) p1 B% R8 i+ d- [9 y6 {1 l set green-light-up? true P$ G u( t* X. g, @
set my-row -1$ m n+ D- [9 h# m; ?4 ^
set my-column -1. A! y( p7 t" g! h
set my-phase -13 D& y$ g3 u7 Y+ s, ?2 f
set pcolor brown + 3
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3 T5 H2 H; F; c/ Y ;; initialize the global variables that hold patch agentsets
5 J$ h1 o r* p( R4 Z4 e set roads patches with
5 `' v; j' J4 b. h: p h) p( v [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
8 B$ j! q2 \7 D/ f9 L# i4 V4 C- G (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
5 W( d( V, K- ~/ H/ g' R set intersections roads with( h H. q& j; R0 k2 H; ~% R2 D
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and8 x- t) ^ o. r# k8 G+ L
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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5 x6 X/ {' @% c6 [* [% a: H1 s; N ask roads [ set pcolor white ]; |8 n2 @# Q5 y3 }( v
setup-intersections
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8 c D: t# J; U# D. `其中定义道路的句子,如下所示,是什么意思啊?
6 S# {$ ^( O; o3 _% F' ~6 y set roads patches with$ I8 {% P8 t) n* X9 h9 c
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
) n% Z; w' z5 |4 l/ Z4 |* z( N (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
4 F; e2 d# U1 k: F: p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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