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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。
& X& P( w" u' fnetlogo自带的social science--traffic grid这一例子当中,
6 G8 R* U" g7 Uglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction
3 c E& H8 f; { grid-y-inc ;; the amount of patches in between two roads in the y direction- X% ~1 t1 m' T& P
acceleration ;; the constant that controls how much a car speeds up or slows down by if# _/ U$ `7 c$ P+ K# o
;; it is to accelerate or decelerate
) _* ^% f+ V5 n3 @ phase ;; keeps track of the phase" C- p# Z- I8 V9 I6 {. G) `/ `) S: ~
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
) E' q" u+ P V+ y current-light ;; the currently selected light+ t+ w4 _' m8 z2 @( B* w
; J6 Q* r2 I+ d: g3 B ;; patch agentsets: `6 M% b# [/ G4 _# k. b
intersections ;; agentset containing the patches that are intersections& E# S6 W! R3 o
roads ;; agentset containing the patches that are roads0 ?9 R3 f9 c* q+ b7 c) j0 d1 `+ H6 v
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$ E: p [- s$ c; V& k% vturtles-own
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speed ;; the speed of the turtle' Y2 a7 n8 E) u" ~& z4 k
up-car? ;; true if the turtle moves downwards and false if it moves to the right
7 C; w) g9 d& M+ u; B5 Z) B wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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7 p S& |" ]; Y9 ~% g7 O O intersection? ;; true if the patch is at the intersection of two roads
/ { S: C. B8 _ green-light-up? ;; true if the green light is above the intersection. otherwise, false.
/ _6 d/ i$ R) b: @7 k& T: K ;; false for a non-intersection patches.! @, d+ I% X. C/ _% c
my-row ;; the row of the intersection counting from the upper left corner of the+ Q; W6 {2 a) V* J' ]
;; world. -1 for non-intersection patches.
( a" ?: E( C( s6 D; R: ~ my-column ;; the column of the intersection counting from the upper left corner of the
4 u" m2 q+ r- g2 Z& Y% }' B: t8 V ;; world. -1 for non-intersection patches.
3 f2 o+ |2 A1 Q+ F3 K( r my-phase ;; the phase for the intersection. -1 for non-intersection patches.2 G9 C) x& P# t% }
auto? ;; whether or not this intersection will switch automatically.' f+ \: u7 Z( T' Z! d
;; false for non-intersection patches.1 {9 D: U1 G" K8 z2 Z9 J
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;;;;;;;;;;;;;;;;;;;;;;
. {. J* R6 R5 i8 @) G6 |;; Setup Procedures ;;
% k4 c$ B& _. L5 W% t;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.
; Q9 Q* ?6 @( x5 U) d! R8 D;; Create num-cars of turtles if there are enough road patches for one turtle to4 _4 i- h* }2 R- N$ o- x
;; be created per road patch. Set up the plots.
* Y) B; } s; z- p$ D. g# @) Ito setup. d+ e- ?+ p! A8 F6 e6 A% Q
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setup-globals
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. L# g* O; H# \# S+ m ;; First we ask the patches to draw themselves and set up a few variables/ ^, [) _* `8 q" P, ]4 K
setup-patches: U2 @! Z; w/ d0 M
make-current one-of intersections
+ f6 j$ K, d: G9 t/ } label-current. `. K/ u2 C; x7 c) @
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set-default-shape turtles "car". V: L) u' b# N
1 V% Z" Z0 @' {- j2 A$ h$ A if (num-cars > count roads)
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5 e" V P0 ]) C$ V1 }( }6 x" x2 J1 `2 h user-message (word "There are too many cars for the amount of "
4 r2 V4 t- S8 N- ^3 `# V "road. Either increase the amount of roads "
' {' t' W. T# O "by increasing the GRID-SIZE-X or "' L k6 S. \' ? C! }
"GRID-SIZE-Y sliders, or decrease the ", r. U! {+ \; h- q' v9 x5 {, C
"number of cars by lowering the NUMBER slider.\n"( S: J$ q* I7 U+ |9 w$ o1 [7 J7 m
"The setup has stopped.")% B1 \* s1 v' j6 ]
stop. Y& s+ n b+ N5 x; S
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. Y, \- \: }6 \( T1 W ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color- n5 M; P1 {6 V+ Q) ?
crt num-cars
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( z& {! D* {/ H% p$ k" F setup-cars
" Y3 q: H; |. z: T8 o7 z set-car-color
( L' z" ?9 z8 s& v ?4 F# r2 e$ I% o record-data
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;; give the turtles an initial speed
2 ^( P& L. }* w# b4 V! P/ V# q1 } W ask turtles [ set-car-speed ]
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reset-ticks. _4 o# Q4 w# D0 p, M: k
end
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' e+ _: L9 x# ?. z2 c0 j% j7 n;; Initialize the global variables to appropriate values3 f) p+ c: H. |4 l) p
to setup-globals
; @- _. q. b, c' N set current-light nobody ;; just for now, since there are no lights yet
/ O6 {: u- P9 Y1 V set phase 0+ ^+ i( M4 X4 j/ E$ N. i
set num-cars-stopped 0/ |6 k( z! i. m; H
set grid-x-inc world-width / grid-size-x
B% [2 {: A' }2 z E1 b q4 j( _$ t 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 boundary0 q" K9 p) R g+ H( Q
set acceleration 0.099, X) k4 u2 O% l$ E
end5 ^* F M# v' ^8 C- O( z3 T
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets," c' v) v d! s5 @+ y- n) t1 G
;; and initialize the traffic lights to one setting: w) r6 F4 M+ h
to setup-patches3 C& U; \7 a* _# T7 N( d( {& c* l! `
;; initialize the patch-owned variables and color the patches to a base-color
2 \# y, u @7 V; k0 T8 e ask patches8 j$ q0 T- X R# ?& F" I5 C
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set intersection? false
8 O1 P; L6 |% e5 |2 \6 n set auto? false$ N( |, U, f O& h8 U$ Z# P
set green-light-up? true
% i# p7 c, q0 X2 Y) D0 z set my-row -1
, Z9 B' M; \7 d- A- y set my-column -10 O% s1 c" ]3 n* C1 p
set my-phase -1
' P# X! Y/ D6 c8 C( C/ x set pcolor brown + 3
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6 a9 h1 Q3 o+ `7 g ;; initialize the global variables that hold patch agentsets
/ V( Z; |9 a# | set roads patches with
! X) H6 Z _6 e" K [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or: a( N: a' {: E) g% p' b0 h
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]4 n, ~0 b/ J4 h
set intersections roads with
# ~- E) J6 ^. u- ^ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
. i; Q3 k4 S# \5 J (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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3 \& |$ a+ A. L ask roads [ set pcolor white ]
_3 Z( ?2 L: O: |! d/ l. A$ W setup-intersections+ C) S: s& j! [6 _' \7 ?9 |5 T
end3 f+ W* X/ Q' k9 n$ j
其中定义道路的句子,如下所示,是什么意思啊? Z: I6 n' ]0 B5 a
set roads patches with" {; K7 v/ N6 y& M& Z2 t) P: Z
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
( ~$ }/ W3 W: d) }& h' @( C Z, L (floor((pycor + max-pycor) mod grid-y-inc) = 0)]- C4 g9 f X( f9 U9 L
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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