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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。 T& E' x, l# n8 }) n/ ?& `. |: [
netlogo自带的social science--traffic grid这一例子当中,
/ F" c# A2 ?2 A) Q4 rglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction
8 L/ p7 S; r6 l% Y, q6 H. F grid-y-inc ;; the amount of patches in between two roads in the y direction' ~/ d- _1 I% {8 a
acceleration ;; the constant that controls how much a car speeds up or slows down by if
" @3 F7 ?; [( d0 Y! N ;; it is to accelerate or decelerate5 d }6 k/ B. W
phase ;; keeps track of the phase
/ R9 r/ W5 n/ k+ s2 z9 O) `9 \ num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure- E: [/ e3 e& t- I5 I0 @9 {0 _
current-light ;; the currently selected light
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;; patch agentsets
, D& H8 L; k" ~8 m intersections ;; agentset containing the patches that are intersections, N% v8 A( h& {8 p$ r
roads ;; agentset containing the patches that are roads
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- i0 h8 W, K) Xturtles-own
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$ E0 _) D: r0 g& n* A# E: h1 I speed ;; the speed of the turtle
* [5 X) n1 a0 w6 D% [) O# o# v up-car? ;; true if the turtle moves downwards and false if it moves to the right8 h b% }. H& I
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 z% }4 v4 r$ i- R Q intersection? ;; true if the patch is at the intersection of two roads
1 i# t1 z% r! u3 F1 J) r, ? green-light-up? ;; true if the green light is above the intersection. otherwise, false.! R$ a5 v7 m) E
;; false for a non-intersection patches.
7 X+ g. U. h& t, P my-row ;; the row of the intersection counting from the upper left corner of the
% l+ z6 }- G" n& V ;; world. -1 for non-intersection patches.1 b( I. W0 @4 h, U ?! M0 g: K- C! r
my-column ;; the column of the intersection counting from the upper left corner of the
. \" X5 H- U C7 G c e/ d ;; world. -1 for non-intersection patches.$ [( J* \0 p- Y9 c; W
my-phase ;; the phase for the intersection. -1 for non-intersection patches.* D) Q3 \) z8 B0 f3 c7 ]
auto? ;; whether or not this intersection will switch automatically.% ?4 b9 s6 w# L) \
;; false for non-intersection patches.
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( `$ y% W! A* R8 q;;;;;;;;;;;;;;;;;;;;;;' C( g& a+ B7 A( H3 o
;; Setup Procedures ;;$ R) u; l9 q/ g' l- f- c
;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.+ |* H! V! w* C q6 ?+ I
;; Create num-cars of turtles if there are enough road patches for one turtle to7 @$ n! I7 D R, D1 F9 q
;; be created per road patch. Set up the plots.
8 M2 G5 k9 y3 w8 m. T+ j8 d( @to setup3 g3 P+ O$ X2 c3 e
ca
, `8 d* ?, r2 \- ~+ x setup-globals
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: H0 F8 O% A- R& |( r4 R ;; First we ask the patches to draw themselves and set up a few variables9 z: O, n. S9 V* G: N7 {" m0 {
setup-patches2 W. Z2 B8 R6 f4 y5 y" m
make-current one-of intersections
1 C0 l1 T! P' s8 ?" I$ @# t label-current4 n: t# R& [0 w4 c R& S
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set-default-shape turtles "car"
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if (num-cars > count roads)5 B5 G. x. R6 I( r5 S; p }
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user-message (word "There are too many cars for the amount of "/ C5 x# M' @3 h' j1 z( B
"road. Either increase the amount of roads "+ N) W, Z' A1 J0 `. d9 ?
"by increasing the GRID-SIZE-X or "
* S0 [+ X) F% c+ Y3 u* x "GRID-SIZE-Y sliders, or decrease the "
# K' h8 w1 T& e: N3 d- p "number of cars by lowering the NUMBER slider.\n"' f' E# d2 z; p. ~. D$ R+ y6 q4 l5 r
"The setup has stopped.")/ M& G- ]) k; d8 V2 e; B
stop7 U) r: [! u0 [
]
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' H* e$ U9 u- `+ \ ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color6 F( m7 M# v; Z% Z4 X/ |
crt num-cars1 h, v) _6 }; N6 k/ E0 x
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setup-cars
! [6 c# m5 [% }: d set-car-color
. F: p9 {" n3 t# | record-data$ {% G& m- r6 v' o: c4 F! F
]
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) d' X5 x, z) C, ^: B2 j ;; give the turtles an initial speed
" a" Y9 y4 y4 ]; P ask turtles [ set-car-speed ], L+ X! K5 u' b% ^8 I* f
3 G8 T5 W0 a" F! m- }& H! U reset-ticks
* g% k7 ~- R1 P1 s# s' l4 Lend
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+ n. l/ x- M$ J# x, A, I! A: {;; Initialize the global variables to appropriate values
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" |9 y) h' S7 w' X4 v- A set current-light nobody ;; just for now, since there are no lights yet
, v: s) r# c8 k7 a, {0 N7 I7 u set phase 0" A+ E, S* `; j( g0 P
set num-cars-stopped 0% E$ n6 d% J$ g3 y/ \
set grid-x-inc world-width / grid-size-x
- W7 Z- z. k: Q' \4 b1 O! T set grid-y-inc world-height / grid-size-y
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9 @9 @" x1 \% D ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary7 u5 o3 S/ n; o
set acceleration 0.099/ s& Z+ ?8 M! Q. Y" K0 j
end
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9 E' ~0 h% \3 P6 o! y0 t) S;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
* v$ \! a! G x8 n$ e* r+ [9 ~;; and initialize the traffic lights to one setting
" r1 X/ Z5 D+ K$ e! Nto setup-patches( e7 I+ _- t4 o; J, [! x
;; initialize the patch-owned variables and color the patches to a base-color
2 }6 N& ~& c/ g% {+ ~7 E- y ask patches A6 m3 R# ], n
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set intersection? false
# g4 m: O8 Y5 F- U" a: P) y s0 f set auto? false8 Z3 g/ _) ?' N+ O5 e# i C
set green-light-up? true
3 ?$ t0 r6 z9 z, e* w: {3 q set my-row -1
1 Q; x4 O1 Y- V3 K" C. G set my-column -1
2 ]' ? ^3 g4 u0 z: g0 b& d% q set my-phase -1 ]5 f% J7 Q2 p/ A+ @4 H
set pcolor brown + 3
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6 k. |3 q) ?2 A/ p8 V7 _ ;; initialize the global variables that hold patch agentsets
) n+ A( ~) q! @! w9 l set roads patches with
* |' X$ l- w; r [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
( t$ d% I B" @8 g. g (floor((pycor + max-pycor) mod grid-y-inc) = 0)], y' c( g& [2 T( e4 i d
set intersections roads with$ U1 d% w+ q; J; ]8 y! a
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and3 a8 K7 H1 v& d' x: p
(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?- D c6 {: Y+ b; n0 G0 U
set roads patches with
/ a+ W/ G: Z* V( A$ E [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
: o! f0 Q. h [ (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
. x7 Q' ^7 n0 ` Z8 u$ j; W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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