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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。' M( @( t. H' Y O7 y
netlogo自带的social science--traffic grid这一例子当中,+ W1 x4 J# T7 a. k% _# [, d
globals
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9 y% E/ B0 P3 I( M grid-x-inc ;; the amount of patches in between two roads in the x direction3 u# o2 D/ y& Y& S3 L/ s$ a
grid-y-inc ;; the amount of patches in between two roads in the y direction$ J4 V- f+ _2 T
acceleration ;; the constant that controls how much a car speeds up or slows down by if
- |2 V) X' {: L0 i ;; it is to accelerate or decelerate
$ x* M2 e( w6 e, z8 z phase ;; keeps track of the phase3 J- h, G% k- C2 O* C b
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure( S0 A2 ~1 ~* @8 u& @2 G
current-light ;; the currently selected light6 k3 A6 Y. z- \' z/ K
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;; patch agentsets
7 y& }2 H5 I' A% z9 o M6 i! P! D intersections ;; agentset containing the patches that are intersections% ?4 r5 L- b4 a( x3 d! S; h
roads ;; agentset containing the patches that are roads
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turtles-own
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5 ?3 ~7 J0 ~6 `2 P' I& M4 h speed ;; the speed of the turtle
! o1 U' o' v& K% k) D, O+ { up-car? ;; true if the turtle moves downwards and false if it moves to the right6 e3 @6 W, K0 o7 W" Q/ k
wait-time ;; the amount of time since the last time a turtle has moved) @. R6 @% j7 a D6 e
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% u0 e6 l- q: h. k8 A3 H% cpatches-own
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intersection? ;; true if the patch is at the intersection of two roads
5 H/ W" k/ e( X6 x" S* H green-light-up? ;; true if the green light is above the intersection. otherwise, false.
- Y4 b+ X, x& `, s( ` ;; false for a non-intersection patches.
3 Z0 u0 s' X+ f' T5 E' i; q# h my-row ;; the row of the intersection counting from the upper left corner of the8 T! m& a% Y( V) u6 _
;; world. -1 for non-intersection patches.: ^) F* d+ V* z. ~- i6 M! a
my-column ;; the column of the intersection counting from the upper left corner of the/ l& v+ |! o2 R% \: ?% K0 N+ f/ @
;; world. -1 for non-intersection patches.
) P/ E: M; p5 o' A7 ]' W/ q, c my-phase ;; the phase for the intersection. -1 for non-intersection patches.
9 r6 H0 Z/ H- I; C* O# x auto? ;; whether or not this intersection will switch automatically.4 v2 H* w" X5 Q2 c+ c8 y
;; false for non-intersection patches.0 Y& h0 E9 d7 i* v
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;;;;;;;;;;;;;;;;;;;;;;( L( `- X$ k" m5 B0 A$ K J
;; Setup Procedures ;;
" I6 y/ F+ d0 D d3 r2 F& J1 O;;;;;;;;;;;;;;;;;;;;;;0 e( A5 Y; A1 A' J- t
" E+ O9 b2 i3 d# R/ X;; Initialize the display by giving the global and patch variables initial values.# {5 I( S" G* a
;; Create num-cars of turtles if there are enough road patches for one turtle to
. F- [: T- J: l0 g;; be created per road patch. Set up the plots.
. d! ?8 z3 _, l- J# Pto setup
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setup-globals
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;; First we ask the patches to draw themselves and set up a few variables, f1 Z# D+ ?- j' a
setup-patches
+ v/ m! R& v1 u make-current one-of intersections7 {1 Q2 g9 Z8 e7 o+ b9 G% U8 h
label-current1 P% I( I3 X, K
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set-default-shape turtles "car"
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2 _) _8 J& d. q' R if (num-cars > count roads)' C% F4 M/ ~4 A+ m
[
& _5 c9 ]; L7 e V) i0 w user-message (word "There are too many cars for the amount of "! \4 P8 q% w1 s
"road. Either increase the amount of roads "1 U* Z- O* S' t! a
"by increasing the GRID-SIZE-X or "
+ D- [) g* s* Q4 e0 u1 P; v# k* Y "GRID-SIZE-Y sliders, or decrease the "
4 X3 d* u; f- F "number of cars by lowering the NUMBER slider.\n"
4 O+ O0 F+ _9 x! ]: V "The setup has stopped.")6 M3 h D6 ^% A3 \- W+ V( c. ~3 m
stop0 F+ K0 N$ z* Z! T/ {- l/ h# L
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# Q5 U, {9 b( F2 ?: e& x! w ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color' A0 Y3 a: v% N/ d2 E
crt num-cars
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7 f/ U a V9 M- n( R setup-cars/ S* Y& H5 b: a) w' s
set-car-color
, n. \9 o' Q" H( q! L7 e record-data! i8 T# ~2 O* a2 [9 ?' M c( Q8 ^% E
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;; give the turtles an initial speed
: {- X! K7 k. W5 L* I5 j3 f5 [ ask turtles [ set-car-speed ]
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reset-ticks# ~" ] s+ }% M' H
end; c0 M! m' c# X. i+ }( F! ]% S' o
9 N4 o- v, F* F: `' M0 c( v;; Initialize the global variables to appropriate values t( g# `) e! J T
to setup-globals+ j( ?6 z1 u1 G) I
set current-light nobody ;; just for now, since there are no lights yet
e1 b1 G, B; P% w! @; b set phase 0* w0 E0 X: d$ T" _6 L
set num-cars-stopped 03 @* X& ]! \" {3 [* T# r2 Z
set grid-x-inc world-width / grid-size-x! U/ h5 K# } x5 {* q
set grid-y-inc world-height / grid-size-y
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: Z4 }8 _% Z3 O2 G+ _ ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
( F3 A! \4 o* h9 ?9 I. L: Y1 s set acceleration 0.099
# z8 T2 C3 g: v3 n! D4 E) s: O9 y5 {7 Tend
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
2 E! a2 V( q% `& N, N! k1 |) K;; and initialize the traffic lights to one setting
: ~! h) @1 z) T% Ito setup-patches
% T% u( ^. o, j5 `6 e; i$ W ;; initialize the patch-owned variables and color the patches to a base-color- Y8 G) k A# }% m8 p
ask patches" a! A) Q2 C$ L3 I
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) T' w( [8 I! d0 ^ set intersection? false
& l: k2 V* K' F6 }/ E set auto? false
0 S2 T4 Q8 J0 d: d# M! q5 y set green-light-up? true4 k' X l, a! u) p& f
set my-row -1
6 h# I) B+ K& v! j5 z# ] set my-column -1
. I6 r5 f, C$ {% C( m set my-phase -1' w1 O* v3 M* g5 @
set pcolor brown + 3/ c9 s( n( A7 R/ E, n
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% q# O. T5 C% { d" P ;; initialize the global variables that hold patch agentsets9 Q- Q; ~4 s$ U2 {/ G. P
set roads patches with# j8 X& Z: S( x# o0 _
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or$ B) o$ Y9 U" d' N
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
0 q) x0 |6 B: A9 N+ v set intersections roads with0 J) h. ]* E* r" D5 h1 ^. M6 I
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and5 K1 u0 H, \* Z% m4 t
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]6 m6 h. Y, T" B( ]
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ask roads [ set pcolor white ]
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end
` ?) j6 ?( t其中定义道路的句子,如下所示,是什么意思啊?8 i" \: I( A8 n* W$ H3 L, G
set roads patches with
- D: c, b( u5 b' X; _; Y1 _ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
. Q& r F0 v; T3 A (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
- |; i% ~% |, j- p7 y6 { o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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