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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。" z8 d6 N7 h' X/ j. e( c
netlogo自带的social science--traffic grid这一例子当中,
* h3 |) C- W. `, Xglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction( a9 r) m4 M! T
grid-y-inc ;; the amount of patches in between two roads in the y direction
" ^1 U \# ^ @$ C9 L4 I acceleration ;; the constant that controls how much a car speeds up or slows down by if" N- P" y* Y, F+ N3 B' s
;; it is to accelerate or decelerate* F3 `) E1 |2 c) [% M" [/ W
phase ;; keeps track of the phase5 m& w% K- u+ F# L
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
8 a# f3 w# z2 c! K9 w( l4 Z current-light ;; the currently selected light9 v: {8 A. B7 X% p, v
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;; patch agentsets% B2 A) N. l* u) G2 `
intersections ;; agentset containing the patches that are intersections0 \$ }& S& A6 L# t# u( O% P
roads ;; agentset containing the patches that are roads, C' B1 o) I' J' \- ^2 J. Y4 x( W
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turtles-own$ A8 X* t% u. {+ d6 i! b8 R) X
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speed ;; the speed of the turtle
' p( f! [4 c4 s up-car? ;; true if the turtle moves downwards and false if it moves to the right
( C, N! U; X7 i" V+ B+ X1 E wait-time ;; the amount of time since the last time a turtle has moved
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7 {; B' S, S( Y. vpatches-own
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/ W% k9 j4 F9 F; [# e( u( w1 C* `% o intersection? ;; true if the patch is at the intersection of two roads+ ]4 T4 U, K; O- F+ C) z
green-light-up? ;; true if the green light is above the intersection. otherwise, false.7 H) ]# _, |3 A: w2 J& O
;; false for a non-intersection patches.2 U- M1 r+ t2 E3 Q& E2 r1 Y
my-row ;; the row of the intersection counting from the upper left corner of the
% Q5 H) {# ?: \8 W9 j8 ~ ;; world. -1 for non-intersection patches.
3 W3 w5 |$ e) C" Q1 ]; S5 l my-column ;; the column of the intersection counting from the upper left corner of the
% b3 I9 K4 I6 D) S ;; world. -1 for non-intersection patches.2 K( s* H+ [6 z# x% i
my-phase ;; the phase for the intersection. -1 for non-intersection patches.5 Y7 o+ F. P9 A' d, f
auto? ;; whether or not this intersection will switch automatically.
, T; d8 d* y) k ;; false for non-intersection patches.
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; n+ c6 b+ Y* w* J; X;;;;;;;;;;;;;;;;;;;;;;
3 s( b3 A% T0 |" p7 c8 k/ Q;; Setup Procedures ;;
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, m# f) B! n) e4 m! t) F;; Initialize the display by giving the global and patch variables initial values.
1 O* ~; b; r- t' ~3 q;; Create num-cars of turtles if there are enough road patches for one turtle to' R" ~$ U3 T, k2 k' `
;; be created per road patch. Set up the plots., y+ Z) o& b4 j
to setup
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8 f$ H* V) `7 F1 A' \ setup-globals+ ^ z# n) S- ?2 U4 ~0 y! g
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;; First we ask the patches to draw themselves and set up a few variables4 L) u0 [) c2 P" e& o" \/ |( T
setup-patches
. S, ]2 o7 g# n- K( M* V1 c make-current one-of intersections
# E7 ?2 ?, @2 s6 y! h/ |2 _ label-current' _0 X8 q. K5 z) {
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set-default-shape turtles "car"
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( A: O: V0 {' e, N if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "2 Y( ~4 v: z V* y$ _. P
"road. Either increase the amount of roads "; R. \& ~, k* I# H
"by increasing the GRID-SIZE-X or "
3 w6 F3 }; l* [* ^ "GRID-SIZE-Y sliders, or decrease the "
/ P4 v* _! U4 t( _9 Y "number of cars by lowering the NUMBER slider.\n"- C/ ^; t, T" b% S2 P; `- j( y& W
"The setup has stopped.")! u7 t( w" x, {* m J, j7 k) A
stop( T ~* G9 r2 p; r$ k! G/ R& K8 n
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
: [- T4 B, R( x! z# ?! K8 N' e crt num-cars: G$ j5 {9 D# s! {& Z- g6 E
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setup-cars9 S5 g5 y. g9 i! J" o) y* V
set-car-color
6 I. I7 t% w1 Z record-data
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S8 E" m/ E2 R; I! A5 M ;; give the turtles an initial speed5 ]) i9 _- _& n9 |- n9 N$ r
ask turtles [ set-car-speed ]
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9 b' s7 w5 C* L# d* ` reset-ticks
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6 D+ N& |; l& o;; Initialize the global variables to appropriate values; k! \- g H H9 f P" }/ `
to setup-globals
7 ^2 s8 I, p: Q# n5 R. I! k) B) P3 K set current-light nobody ;; just for now, since there are no lights yet. F$ A& r$ \- l y% N6 E4 w% h
set phase 0
# K! @3 R# N1 V2 A" a5 Z set num-cars-stopped 0
2 T- Q+ y$ F; U8 R set grid-x-inc world-width / grid-size-x
# `1 ~( |0 q0 l# I set grid-y-inc world-height / grid-size-y2 _# ]8 k8 S% @5 w8 u4 ?+ p
* F4 b( b$ j/ I0 e+ l$ ^ ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary4 P8 s0 _5 k" x" y, f0 W+ Y
set acceleration 0.099
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
+ {5 o# `) P0 C;; and initialize the traffic lights to one setting' P* R! [# l& K/ P4 I: z( r( F
to setup-patches
. }! |/ R) V2 i2 W/ i3 [( I ;; initialize the patch-owned variables and color the patches to a base-color
& z4 k6 G/ `( W ask patches% |, n# y" [! ?% c
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0 G& D1 X/ a( b set intersection? false$ A9 y8 ?9 `0 C5 J
set auto? false
1 \5 |* O: Y4 ^# D set green-light-up? true d) y: \! p; g
set my-row -1
' y% i# C, N R0 T2 l set my-column -1
+ V& F, h3 M, O: u, x+ A set my-phase -12 D- n! B, E( u+ O
set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets
' ^, X$ }1 Z% ^7 n! c5 S" h set roads patches with" f9 o2 ?3 b+ s) x5 s
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or# |' S+ V" f2 _( }
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]# J/ @9 f2 V- C% y0 ~4 D
set intersections roads with- X$ W2 k0 ~. t
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and# F( l9 t! R8 S( C# [5 y, i
(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?( m' W+ ?' j3 Z. Q
set roads patches with' T. b3 k, w4 P; M: N1 {
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or3 {6 r# V/ b- U3 r
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]) p7 D5 }* {! v6 M) U8 J* d+ j
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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