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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。3 j+ N9 b7 Z9 c$ m3 n
netlogo自带的social science--traffic grid这一例子当中,/ A" w/ p' R* Q
globals$ S% h2 u* N1 \. K
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grid-x-inc ;; the amount of patches in between two roads in the x direction
9 l& N5 X! N6 i9 c0 Q! O, q grid-y-inc ;; the amount of patches in between two roads in the y direction/ F5 m4 l3 g$ C3 D( M
acceleration ;; the constant that controls how much a car speeds up or slows down by if
Y$ [7 K0 i( w* `+ w' y9 R ;; it is to accelerate or decelerate
# o+ X& c* k( }2 l/ x8 b phase ;; keeps track of the phase! F# r$ o0 a$ ?" n/ Y" U; y: Y
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure6 `! Q9 b' N0 B
current-light ;; the currently selected light
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, x$ N7 @0 x# ~5 s6 Y; m$ p ;; patch agentsets4 h8 Y" R4 C* _, O7 ^) A0 Q
intersections ;; agentset containing the patches that are intersections
) X/ c- v6 }3 n; w- u, ]% f roads ;; agentset containing the patches that are roads
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turtles-own
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speed ;; the speed of the turtle s9 K- C: @% U1 b# c( d- b
up-car? ;; true if the turtle moves downwards and false if it moves to the right" S; y, H$ a f
wait-time ;; the amount of time since the last time a turtle has moved
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1 Q- g5 u9 E* r) d# Dpatches-own
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intersection? ;; true if the patch is at the intersection of two roads
4 s9 u5 `2 Z( G green-light-up? ;; true if the green light is above the intersection. otherwise, false.( y% q+ w6 F9 [1 O4 O
;; false for a non-intersection patches.
8 N$ M+ N4 }% s my-row ;; the row of the intersection counting from the upper left corner of the5 l0 {) V3 i0 ]
;; world. -1 for non-intersection patches.* S. {7 Q! a+ m
my-column ;; the column of the intersection counting from the upper left corner of the
9 z8 e9 k+ U! y: K) U, m ;; world. -1 for non-intersection patches.
- _" h1 c# y7 w4 n8 s l& I my-phase ;; the phase for the intersection. -1 for non-intersection patches.
p, i, H; ?4 W; G' [! o! ] auto? ;; whether or not this intersection will switch automatically.
, ]- u ]7 k! C& m+ h x4 i6 t7 O ;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;
0 D- `. R3 T; H3 r4 V$ k;; Setup Procedures ;;
3 }& G+ Y) S8 m; x5 x4 d$ v;;;;;;;;;;;;;;;;;;;;;;& R1 c' g, C+ f
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;; Initialize the display by giving the global and patch variables initial values.
8 s2 C4 ? t0 Z* l;; Create num-cars of turtles if there are enough road patches for one turtle to* P! K! w0 y, k i. X
;; be created per road patch. Set up the plots.
8 z+ n4 S' S+ ~" i8 wto setup
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setup-globals
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( {8 W6 {: U* U/ Z# u ;; First we ask the patches to draw themselves and set up a few variables$ a" }9 b) B4 I$ q! O0 s/ U7 t7 L. n
setup-patches7 a* e- {- V+ B8 Z. w; q
make-current one-of intersections/ W5 i R5 \! P% l! n; [' ]
label-current
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set-default-shape turtles "car"
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if (num-cars > count roads)6 f8 w |; ^+ b: V" ~1 T! [
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user-message (word "There are too many cars for the amount of ", ^/ z# I$ d. B. i/ o; K9 c
"road. Either increase the amount of roads "
! d- k; L2 d; E' V6 I$ B "by increasing the GRID-SIZE-X or "
7 q% W# |# J0 c7 O; p; h0 ?7 \ "GRID-SIZE-Y sliders, or decrease the "
f( S. [8 @+ l# F "number of cars by lowering the NUMBER slider.\n"9 Z8 ~' G+ D5 y* A
"The setup has stopped.")5 |7 I+ W6 r6 a; k8 |; G
stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color- v7 g @# F( O+ t( u, D. d$ x
crt num-cars5 b8 G. K( d6 G6 H
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setup-cars
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record-data
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$ u5 L$ `3 E, W9 K! L ;; give the turtles an initial speed
0 x5 `; k+ D9 s8 ] ask turtles [ set-car-speed ]$ B+ c0 q' h# E0 s/ [- _, C5 W) K+ Y0 w
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reset-ticks
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( f/ t9 R% M- o+ L;; Initialize the global variables to appropriate values
h+ [& @6 E$ @( j4 W0 gto setup-globals" t( s' ]% M8 l3 c4 }5 z5 I' q
set current-light nobody ;; just for now, since there are no lights yet1 D- k' q0 ~! u& l, o+ E, C3 @
set phase 0: z2 ]- J( R2 W9 e
set num-cars-stopped 0& S3 G! p U4 C9 B, F' H, e0 y
set grid-x-inc world-width / grid-size-x
* R5 O; {& d6 Q) x set grid-y-inc world-height / grid-size-y
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* C" ?( Z/ y8 X, X3 Q4 G- f ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
/ ^; {+ ?8 p+ _$ M4 a set acceleration 0.099
( T8 S8 h$ O3 u* q( xend
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2 u) @$ ]% m$ [# n;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
" g S$ }9 H- @5 ^! h& Z# X7 `;; and initialize the traffic lights to one setting* Y5 @' k& j; ?0 N( U- a
to setup-patches
0 i! h+ I; l8 g* c7 }, m3 l0 u. Z9 r ;; initialize the patch-owned variables and color the patches to a base-color, B6 u7 ]2 }9 F. Q% S- S& }
ask patches
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6 ~, j: b+ h" f# G o/ l set intersection? false
& ~, t: m5 Y4 o- \6 C6 D set auto? false
! Q- T' |5 T- l set green-light-up? true$ ]% `6 E% Q4 b J0 d
set my-row -1
( k, _% o* O; {/ {6 }' J set my-column -17 e& e0 y# H, |! j4 _* R% n& S
set my-phase -1, y4 I+ o u& x, W2 j
set pcolor brown + 3# L; \4 `/ B0 \; X! ]) Y# {
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* s. z% k8 h1 o ;; initialize the global variables that hold patch agentsets
2 u5 s9 d8 v4 J+ ]6 [ set roads patches with
0 {( |/ H3 X6 @ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or3 P6 r# g% r6 g# [2 g6 i+ {7 n
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
5 z# x3 \1 _( d4 c set intersections roads with
, B' C, M& b. E y [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
, s1 _) D* B. S2 a (floor((pycor + max-pycor) mod grid-y-inc) = 0)]9 t: z$ T( L; ~2 o* I/ f
; {( l: f. N, R, A- |* b 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?2 w' z: R, r& o- C
set roads patches with" @3 ~8 ?, U2 W! e3 j# f4 }: I
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
- B4 S# q# C1 U8 e" F" I (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
* k Q' } @ b" ~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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