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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。
7 o( \$ U& S: s+ } mnetlogo自带的social science--traffic grid这一例子当中,
2 W! f7 N4 |5 p4 q8 D$ Pglobals; R6 \- f$ T( ~& I
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grid-x-inc ;; the amount of patches in between two roads in the x direction/ L+ F) J- Q) ]# x7 |& K
grid-y-inc ;; the amount of patches in between two roads in the y direction! s1 e5 q8 p, P/ a3 |
acceleration ;; the constant that controls how much a car speeds up or slows down by if' W: }2 ]. y1 G; O* J
;; it is to accelerate or decelerate. v. r2 u+ y; D& P
phase ;; keeps track of the phase
/ X+ b% b8 u) n; ^* z6 S$ \. M num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
; U! t6 P! Q9 U+ G current-light ;; the currently selected light
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;; patch agentsets1 o2 r" ^+ H v8 y
intersections ;; agentset containing the patches that are intersections
* g% P2 t8 F" ?" D8 S& E. ` roads ;; agentset containing the patches that are roads
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turtles-own
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speed ;; the speed of the turtle; j$ X7 u0 `% W5 d0 L8 }2 `
up-car? ;; true if the turtle moves downwards and false if it moves to the right
2 N) d( q+ N+ S' R wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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# l2 U# G) J( v1 _3 I, S2 F6 U intersection? ;; true if the patch is at the intersection of two roads
4 U' R/ f& s; N+ o' } green-light-up? ;; true if the green light is above the intersection. otherwise, false.
0 |$ ^. z9 I# l( o8 V S ;; false for a non-intersection patches.9 p. I4 Z8 ? g x+ B- [* [$ C: P
my-row ;; the row of the intersection counting from the upper left corner of the
% p! i- u8 w* B% O1 ^7 _' P, D- E( z ;; world. -1 for non-intersection patches.
/ w9 n1 j+ c# d* l. b7 | my-column ;; the column of the intersection counting from the upper left corner of the1 n# q( }9 v' V/ M5 g# M
;; world. -1 for non-intersection patches.3 p6 g9 D* C- q+ h9 D
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
2 U: {, _5 U. `; ^ auto? ;; whether or not this intersection will switch automatically.' m0 ~" L1 G2 T) @+ n' L: N# X+ ]
;; false for non-intersection patches.
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4 U) B3 `) t. \;;;;;;;;;;;;;;;;;;;;;;4 Y+ t# r( B5 {$ A
;; Setup Procedures ;;+ M( S8 s7 Y# o! f* u" m
;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.5 x: V% U. h3 ]$ @ o' \3 j
;; Create num-cars of turtles if there are enough road patches for one turtle to
/ R$ ~" F! C4 d- k. }6 k;; be created per road patch. Set up the plots.
$ X+ S2 u5 g U/ k7 R, wto setup2 h) o, P9 o, _: _, K
ca- o6 `& j J( P7 C
setup-globals
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;; First we ask the patches to draw themselves and set up a few variables7 C* b( W" @1 m! K7 ?$ d9 q/ c
setup-patches: i) a! I+ l. X
make-current one-of intersections3 d/ E/ s% E: z
label-current: \* M ?/ \% X& _ j; n, K
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set-default-shape turtles "car"
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if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "
: `( ?7 D; h" ~" l6 T+ T2 n "road. Either increase the amount of roads "
7 k3 @' r. Z [. r% U: c% Q "by increasing the GRID-SIZE-X or "" T! P: u! x- s% k
"GRID-SIZE-Y sliders, or decrease the ") p- u4 l/ p( |0 W/ I
"number of cars by lowering the NUMBER slider.\n"
) i4 W5 k$ t7 w$ t "The setup has stopped.")
7 R+ s% E5 k2 T; d& C; s3 m2 w; t stop- [0 G. U0 a7 _( r* B
]
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
5 y; V! J n7 S& u6 d* | crt num-cars! p; e# X- U" X3 P
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setup-cars
8 ]- M4 s; M1 X& Q3 n7 v3 A set-car-color: b* q* ^, K# o, C2 ^4 ]* Y* Q
record-data
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;; give the turtles an initial speed- ?7 r# c6 T/ B
ask turtles [ set-car-speed ]* ?% H2 E( H8 M* i$ e
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reset-ticks5 w5 B) o8 `, o; \ ~( Q# e
end
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: p& v1 S: O5 p' {7 J% M/ C;; Initialize the global variables to appropriate values7 V# |& c; g6 @2 w
to setup-globals
|/ Y* Y1 D8 d7 p& m' J1 s set current-light nobody ;; just for now, since there are no lights yet# i4 G' f; J4 P: F! R, y3 F
set phase 0 _) Z3 ~3 y( U) ?
set num-cars-stopped 0( {4 D/ Y2 X5 I1 J* Q. K! R
set grid-x-inc world-width / grid-size-x. p; K1 L \% }, h d) \2 j
set grid-y-inc world-height / grid-size-y" H' ^4 `# r# D( w! H* O8 o
% I2 E Y5 M& G, u0 x0 B0 G ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary5 M0 Y3 N' I% n6 ^' p+ Z
set acceleration 0.099$ N8 E( p3 F Q& Q' A
end# L7 U4 _# z+ H; ~5 @
7 ]7 b) }7 H+ p6 G& |3 V7 G;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
, n# e, i4 T! J; a. d+ H' ]" J1 i;; and initialize the traffic lights to one setting
/ s) K( X7 |3 ?to setup-patches5 w2 a- [$ G% \$ j5 ?% b
;; initialize the patch-owned variables and color the patches to a base-color
3 d' O+ x- ]7 a" M7 E. \% h8 X ask patches
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set intersection? false; z, y x! g; g" F" A5 J. ?
set auto? false- _' P$ |1 b/ {+ b
set green-light-up? true/ T0 N7 i- [, h- b' t; Y& q, _ k
set my-row -1
" J. d( D1 x3 `. F# w9 U# | set my-column -1
8 ^* Q2 D/ m H1 m7 x set my-phase -1
% Z& Z9 q* O3 a+ U7 A! V set pcolor brown + 3
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, _* B* C" V' t ;; initialize the global variables that hold patch agentsets
( Z, k7 o; Z# e% _: o set roads patches with
4 b' v0 \0 O) A: l" a [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or! x; s% g7 v; {6 V0 c8 s) ]0 G
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]; x( q, \% `. W/ P5 l3 j9 D. m; r
set intersections roads with0 J" j- k! j. l: J1 h
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
# A+ B2 S3 h6 D. [% @% q5 e" f (floor((pycor + max-pycor) mod grid-y-inc) = 0)]9 I+ a/ O7 K; e' V' A5 |. d4 E* L J6 Z* `
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ask roads [ set pcolor white ]( x' l3 C( T% a9 n7 Q! s4 _
setup-intersections
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! l' c% O- F- T5 `2 R- g5 T; W! F其中定义道路的句子,如下所示,是什么意思啊?
# C' v$ L9 y3 o5 B* @/ z1 M2 j set roads patches with
/ s" E( w' m' V$ m [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or' C8 G5 A$ T! v _& K
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
/ ~. F7 K9 E0 z7 `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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