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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。
. u& ^+ J- l( x, gnetlogo自带的social science--traffic grid这一例子当中,; q( U4 x, }2 M6 A
globals4 N( W8 U# \+ [, g: t
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grid-x-inc ;; the amount of patches in between two roads in the x direction: h7 h: ]& E4 t; ?( |' e: U
grid-y-inc ;; the amount of patches in between two roads in the y direction
b: d& t# B7 K, K acceleration ;; the constant that controls how much a car speeds up or slows down by if- D- u2 ] Q0 a& ]" i7 t5 O
;; it is to accelerate or decelerate
+ Z) a) Q4 f" k/ x% r a$ s T phase ;; keeps track of the phase
, X& m& O2 b* u$ H6 f; }* { num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
. S. x' t/ m! o# I* y current-light ;; the currently selected light
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;; patch agentsets8 ], u$ p8 G. z/ E
intersections ;; agentset containing the patches that are intersections
9 X- a2 I x. t roads ;; agentset containing the patches that are roads/ L8 F" w0 y* w7 c: A% A
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turtles-own
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" \- Y# O( U/ H( G* ^: W speed ;; the speed of the turtle/ b& q' \; z# D' U
up-car? ;; true if the turtle moves downwards and false if it moves to the right
2 d) p5 `$ t5 L& P/ X) G1 T wait-time ;; the amount of time since the last time a turtle has moved/ h N5 q8 |9 L4 F/ a
]
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patches-own
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( g3 r9 ]+ A4 i& F+ ^1 L4 X: X6 C% K intersection? ;; true if the patch is at the intersection of two roads" ?# j$ h, G; ^/ @1 t, w. m: p+ B
green-light-up? ;; true if the green light is above the intersection. otherwise, false.1 ^2 Z: F0 `+ r% m4 x
;; false for a non-intersection patches.9 x6 m' J( m5 }9 R ^6 D; M( i
my-row ;; the row of the intersection counting from the upper left corner of the" s e: X- k, Q, c7 T8 g1 M
;; world. -1 for non-intersection patches.+ Z5 l+ T& z1 v( m
my-column ;; the column of the intersection counting from the upper left corner of the
1 M7 H$ Z. E6 a, b ;; world. -1 for non-intersection patches.9 ^. Y' j7 X, s) W6 m
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
' S3 N6 t) g0 l! L5 g* p" v9 x auto? ;; whether or not this intersection will switch automatically.
% a* \: b- @- x& M ;; false for non-intersection patches.
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3 U3 J* t8 ?( `3 B! ?* w;;;;;;;;;;;;;;;;;;;;;;, n+ k* p8 w F# X
;; Setup Procedures ;;
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;; Initialize the display by giving the global and patch variables initial values.0 g7 d4 ]' _, e# ^& ~
;; Create num-cars of turtles if there are enough road patches for one turtle to
3 c/ x/ N. Y) _5 l+ ^* P% a1 n;; be created per road patch. Set up the plots.- U" ~) \5 i/ s6 n3 _7 c" A+ N
to setup0 A9 s6 h1 j7 s4 [7 a
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setup-globals
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;; First we ask the patches to draw themselves and set up a few variables
# m, d8 {7 ] C( u3 \7 R+ l: |3 | setup-patches
( ^8 m- R: u4 J6 }. X8 f! R) [/ P3 b5 o make-current one-of intersections) U; v7 W! A' z0 Z% P' `4 O0 [. F
label-current+ I' N" D* P- m5 O' ^2 z [
* A/ d+ L+ l; z; T; R set-default-shape turtles "car"
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% w. Q6 w& v4 L/ H: c6 D' W/ q if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "& @! v# u3 @$ V# Q2 a0 O' Q) |
"road. Either increase the amount of roads ". L W6 ~% d! ?
"by increasing the GRID-SIZE-X or "
9 ?7 V, |4 O; U "GRID-SIZE-Y sliders, or decrease the "
0 Y0 ]0 Q6 h6 l( t5 L7 c/ H1 i "number of cars by lowering the NUMBER slider.\n"$ A& } L7 {& M
"The setup has stopped.")
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color5 V; L* }0 P0 `
crt num-cars- U4 }0 S; j8 b; e
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# h0 \: g# p( d7 z, U& [ setup-cars( V* ^4 r3 c4 k9 S' y* P2 S/ f
set-car-color+ g, ]6 u9 E! P, `9 ~+ j& Q) r
record-data' t# _ w# t) d, P- [4 Y
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' S* v6 }/ A+ }( u ;; give the turtles an initial speed
" ^) j5 O* K4 R! y( ]7 v- [+ e' a ask turtles [ set-car-speed ]% k& m' B; w6 ~3 D C/ P& C
$ A- i0 D) D7 e. m g reset-ticks
" Z' s; _7 f' U7 \) eend
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;; Initialize the global variables to appropriate values2 E7 T& [# q: j/ p1 W4 t, K$ F% z
to setup-globals6 e) p( Z8 P6 ]
set current-light nobody ;; just for now, since there are no lights yet1 J4 e4 `6 q( E4 I
set phase 06 O7 t2 K& p/ I* s$ [( d
set num-cars-stopped 0; R! k; a' x# ~# ]+ `( v
set grid-x-inc world-width / grid-size-x0 I2 N" s! ^0 @/ A2 V' P! u
set grid-y-inc world-height / grid-size-y- @' ]" s; H7 b
i( Z# c' g3 w( t ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary" ^9 t) i& X8 A8 o: f$ s- I8 }
set acceleration 0.0998 O7 C! ]) H2 z
end$ R; | m. ~* x
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
* s k( M$ w8 W. V/ J;; and initialize the traffic lights to one setting: }/ g) t) x6 p& c2 ~
to setup-patches
" X1 S* j/ R H# H ;; initialize the patch-owned variables and color the patches to a base-color% o4 s! J C! o g& A+ S% V
ask patches
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% o& N4 s% ^6 C: q+ ^& T7 J' t$ v( ^9 v+ _ set intersection? false
1 o, T, Y, I9 I0 a1 F% e! g& g. Y$ | set auto? false p' o0 c# u/ L
set green-light-up? true
# z: T7 s3 G* |# ~2 H6 G/ i set my-row -10 |6 T3 h! M: |4 K) x
set my-column -1+ u9 n9 c+ _- E. o! i0 L. Z
set my-phase -1
1 a: P% Y: i8 i8 q" U' ?8 t set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets! W w j- S1 m1 D) J L
set roads patches with
1 i* d2 H4 E" z2 z. H [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or$ _. x% f Y0 G; l
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
! F9 A1 G' I: D |% k' h8 o8 T0 x& ~ set intersections roads with1 n( I' ~" o% v) ~/ E2 a$ _
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and, w" |2 T! z9 X" z0 l5 H
(floor((pycor + max-pycor) mod grid-y-inc) = 0)], u7 ]6 k* m u1 T0 G- f
2 I8 G. O. w6 ~6 h. S' H' D1 X ask roads [ set pcolor white ]
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0 S/ ~% x6 `5 q( yend
; K7 T# j! w! d$ o+ r+ d其中定义道路的句子,如下所示,是什么意思啊?
; C; X; N6 i' @3 ?- F. O n set roads patches with* m+ z1 d' l P/ s& ], ^2 x
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or. o$ W# h) u. }* e* H/ @0 I$ v. ^
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
v# w8 H5 m) X6 z p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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