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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。
$ l5 Q/ U, l* K/ v$ D- W4 snetlogo自带的social science--traffic grid这一例子当中,
9 G7 S) t* f- q$ O( {2 K5 \globals
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8 r% T$ }/ m7 a# V* g! i grid-x-inc ;; the amount of patches in between two roads in the x direction
4 g2 Y# t* r. V! @3 b; a) L9 L grid-y-inc ;; the amount of patches in between two roads in the y direction
' U+ I# f& n6 |2 R! s9 ` acceleration ;; the constant that controls how much a car speeds up or slows down by if
, y. {* p W* v" ? ;; it is to accelerate or decelerate) L- Q; r: ~3 P( |1 s
phase ;; keeps track of the phase2 p C2 @- r, F( [: x4 S+ [: i5 r
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure% t$ ]4 U- v5 e/ H1 ^
current-light ;; the currently selected light- d+ s3 K) L& |' N5 R ]; Y
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;; patch agentsets
6 y. X* [$ t3 h2 v& o) A/ l intersections ;; agentset containing the patches that are intersections
; E* z0 j( p5 |4 e# i2 c roads ;; agentset containing the patches that are roads' O i1 J, Y% Y3 J( n* z6 A3 t
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( z( [# ]9 F) m2 w1 _turtles-own0 ^5 E) p/ m/ ?! }/ P, l
[
9 h) x8 G5 G% E r3 [0 D* }- y speed ;; the speed of the turtle7 [8 \ t2 V) o9 _* o; o7 D* i
up-car? ;; true if the turtle moves downwards and false if it moves to the right; n: O9 b, N/ e8 V8 P
wait-time ;; the amount of time since the last time a turtle has moved* ?. c8 Q8 j1 t& _9 n! y, A7 A+ f
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: Z5 ~' Q, T9 v. A2 v6 Bpatches-own1 h' Y7 \$ W9 o8 y# [
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intersection? ;; true if the patch is at the intersection of two roads6 r" F6 V, j9 E9 ]. {- U! M, G
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
( f0 z- L( J+ u ;; false for a non-intersection patches.
5 y5 b2 }8 X; t' k my-row ;; the row of the intersection counting from the upper left corner of the: s( }8 }8 s7 V$ E0 M/ g/ I- ^1 J1 N
;; world. -1 for non-intersection patches.
% O- W; _2 d9 \: M! y6 b5 Z my-column ;; the column of the intersection counting from the upper left corner of the
" D0 t! }8 ?2 q3 `0 E# L( p ;; world. -1 for non-intersection patches.
1 k V/ S* c' M* C! I my-phase ;; the phase for the intersection. -1 for non-intersection patches.
/ E8 K4 r' |# m* |1 Y, U1 ^ auto? ;; whether or not this intersection will switch automatically.
0 d j6 Q( W. X0 w: x0 A ;; false for non-intersection patches.. ~0 \8 |- W/ Q$ ^* }% Y: k/ f. w- h3 G
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;;;;;;;;;;;;;;;;;;;;;;
( z v( W7 c7 Y& f;; Setup Procedures ;;
$ v& f8 c+ x" I6 u;;;;;;;;;;;;;;;;;;;;;;. G1 a8 X( V4 \! k, \, [$ V# V
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;; Initialize the display by giving the global and patch variables initial values.8 B6 T7 ]6 C7 f' h/ j
;; Create num-cars of turtles if there are enough road patches for one turtle to& {* y0 r, V5 v' `2 i# `
;; be created per road patch. Set up the plots.
- h8 D; ?: e# X1 o4 Tto setup
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; G* C' ?0 N( c setup-globals( v+ j: |" B1 B, I" A J2 ]
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;; First we ask the patches to draw themselves and set up a few variables
5 g7 \6 `9 m6 g9 [$ {3 D setup-patches2 `% B1 ? B2 [3 H
make-current one-of intersections( }% Q2 j5 H4 T
label-current
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. L, |7 F& ~& a9 _1 P9 H e set-default-shape turtles "car"* m7 f( l9 x1 u7 z+ r# h
; R3 x/ ~& G) ]0 {6 m4 a3 k if (num-cars > count roads)
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/ W, t6 X! o: \3 ^6 c! H user-message (word "There are too many cars for the amount of "5 }% V3 ?, R I. h
"road. Either increase the amount of roads "
- S( S1 ]7 T- b3 p& G "by increasing the GRID-SIZE-X or "' e/ g. S, B7 F# }
"GRID-SIZE-Y sliders, or decrease the "/ R/ C! O( M% _( s. m
"number of cars by lowering the NUMBER slider.\n"
+ ?. P2 O& l9 r0 N8 g4 ]) I "The setup has stopped.")
, w/ [ V1 W+ Y$ p p5 R0 z stop; s: L. Y( [! Y5 k& C
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color; P0 @9 n$ |6 ~4 |4 K4 B f
crt num-cars! j u8 C `! p7 s4 a% `
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setup-cars. t5 p9 v8 h! H; m- L
set-car-color
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;; give the turtles an initial speed
+ G# K5 p) w) \/ x( S4 I6 s; \! L ask turtles [ set-car-speed ] C5 e' o$ {$ G# @
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reset-ticks( `9 I; v; ]0 v8 i0 }
end
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# j* `2 x- X9 J3 [! {6 D4 b# h;; Initialize the global variables to appropriate values, Z% a( J! c. a& ?) o
to setup-globals
' a. d( @4 j9 O) O9 S& P" ^ z set current-light nobody ;; just for now, since there are no lights yet
+ T1 l: t. {3 ?4 Y/ } set phase 01 {; r4 r7 \8 O- {
set num-cars-stopped 0( m% T& z9 s8 u/ v" C# e0 q/ I; Q
set grid-x-inc world-width / grid-size-x! x; I- ~. N( f- u9 z3 [) d( Q& A
set grid-y-inc world-height / grid-size-y0 e; W3 f; Q$ o; L; z, O
Q; ], B# y+ L ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary6 g) T1 E1 r' G2 t) F* i6 K
set acceleration 0.099
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5 U% i. X/ J) L# y5 i+ s9 x1 [, B;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
8 i/ P# f; ]+ M. b;; and initialize the traffic lights to one setting
7 L0 `& V8 i. Fto setup-patches/ m$ U3 V/ F6 _; l7 W, b6 i
;; initialize the patch-owned variables and color the patches to a base-color: S, B3 k4 c( b0 A( ^
ask patches; Q4 x) e5 w" z
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set intersection? false
x0 y. [ N% K+ f set auto? false
$ n: I2 R2 M u* I4 l1 i set green-light-up? true2 E" Z" s3 a: _- E3 J- |; y
set my-row -1
# C! ]* v) I* k9 e. ] set my-column -1$ r8 d& p6 t1 R
set my-phase -1
. ~: P# }& M) T3 h; I. p2 [# ? set pcolor brown + 3 f% {- i2 C: l8 J8 m( u0 A5 P+ i
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* R8 \, ] ~1 j ;; initialize the global variables that hold patch agentsets
' w; j" S% R3 J2 m2 \ set roads patches with( R- `+ i, R2 j) j9 j( m U6 F
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or& K2 ?0 R& F2 H+ i9 ?
(floor((pycor + max-pycor) mod grid-y-inc) = 0)], y% G: a: ]) |& p4 e! l
set intersections roads with M7 ~% n3 y0 \' i9 D* R" L
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and! a- H0 }: E) i3 p
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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$ Q' {: G) y8 Q1 q' n: _. C4 ^ a ask roads [ set pcolor white ]0 _0 g6 |, }8 o' h# u6 V
setup-intersections
" [* }% W+ P1 L% V A4 Rend
/ P4 l/ v- U' A7 ]3 R0 q S其中定义道路的句子,如下所示,是什么意思啊?
. P1 j$ t3 L7 y# H' F% f* J! T4 o set roads patches with; |* d: f/ p8 {0 p4 B
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or; G" u' I# d5 \
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
! D# P7 n9 K! ]) q9 Y0 E, C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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