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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。. P9 X4 U; m# U
netlogo自带的social science--traffic grid这一例子当中,6 e7 C% J0 W1 H3 ^6 c b% o
globals
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grid-x-inc ;; the amount of patches in between two roads in the x direction
) V0 d/ m% ^7 z& q9 I4 r grid-y-inc ;; the amount of patches in between two roads in the y direction, A c+ W j6 o+ `
acceleration ;; the constant that controls how much a car speeds up or slows down by if
! u7 B$ S* w7 a$ W ;; it is to accelerate or decelerate" M" \& e2 A5 g# ?3 P, }
phase ;; keeps track of the phase
1 s# }+ {5 b3 D4 q% H0 ]4 B- V6 h num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
, r X- _3 _/ \ n current-light ;; the currently selected light
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8 }4 Y- k/ Y1 N- V4 A ;; patch agentsets
# Q. q. y' s; S( ? intersections ;; agentset containing the patches that are intersections* v0 m( k7 r* j
roads ;; agentset containing the patches that are roads3 s2 _* c$ u, o$ ] v% _
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! ?2 X" K8 G" X# U) B% x- vturtles-own
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speed ;; the speed of the turtle w9 V) l* a# u5 U) s
up-car? ;; true if the turtle moves downwards and false if it moves to the right
, V z7 I+ f) C! J& w/ l/ M8 H0 j3 X wait-time ;; the amount of time since the last time a turtle has moved- i6 c% u! P' o9 |: l9 C
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patches-own( p$ a" E$ A( v% ^. W
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intersection? ;; true if the patch is at the intersection of two roads$ R5 x# S' W5 h1 U, N8 N
green-light-up? ;; true if the green light is above the intersection. otherwise, false.' I! @0 k' y1 ~1 R' D
;; false for a non-intersection patches.
8 Q; L8 C. l: _8 w5 D my-row ;; the row of the intersection counting from the upper left corner of the* i* l0 }% T8 ~: K& J
;; world. -1 for non-intersection patches.7 E G; @& n5 C/ y7 l; c1 H
my-column ;; the column of the intersection counting from the upper left corner of the
, u) M) O3 X; U9 E$ l% L ;; world. -1 for non-intersection patches., O/ ^4 ~3 T1 w5 }; p* y+ P" A
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
7 f* k) \0 y- c6 l1 ~; Q auto? ;; whether or not this intersection will switch automatically.; ]9 |9 H- j# G9 Y# G4 v/ q
;; false for non-intersection patches.
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2 `# { P' j X, r. o/ u;;;;;;;;;;;;;;;;;;;;;;
" ^/ q4 Q1 Z" \0 r. R;; Setup Procedures ;;' i3 S0 R+ d/ z3 y, K" r" Z
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;; Initialize the display by giving the global and patch variables initial values.4 w1 K3 f" k1 B7 F, s8 \7 e
;; Create num-cars of turtles if there are enough road patches for one turtle to
8 c9 r9 Z+ r- h9 [2 ?;; be created per road patch. Set up the plots.( j0 }: ?6 P5 w3 }
to setup
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setup-globals: Z" ~. K- h, A6 m
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;; First we ask the patches to draw themselves and set up a few variables
1 v( H8 t( j6 m" N setup-patches- i# R4 j4 D5 O5 h
make-current one-of intersections6 m) u; l d" X/ ^
label-current9 V+ G2 b2 A; v3 k# f
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set-default-shape turtles "car"$ T$ ]6 [3 [8 Q% W' a# I5 K+ C
3 W% S D! d4 f% S; D& c$ c if (num-cars > count roads)
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" X l0 U- y& _4 r( p- T# d* w. ? user-message (word "There are too many cars for the amount of "
: H# Y$ {" V3 z! u2 [; U7 | "road. Either increase the amount of roads "
/ N% R N* ]/ d% D3 k: C0 ] "by increasing the GRID-SIZE-X or "
$ U9 H9 l5 U( y% s* M% K2 a "GRID-SIZE-Y sliders, or decrease the "
0 Z k7 r( ~0 G7 v5 Z5 U "number of cars by lowering the NUMBER slider.\n"7 Y7 I. ^; w2 f4 o n4 U
"The setup has stopped."). M# v9 V. W5 `( r: p7 C+ @
stop
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- a, V/ E1 C/ M" _6 _( ~1 d ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
" Z3 x& }- o z$ `; @6 R crt num-cars
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setup-cars* U8 a7 T: t$ s, u
set-car-color
8 V* M% F) w6 I2 @; | record-data. }/ V: q M& o }1 k" N. [
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;; give the turtles an initial speed
* H6 I3 _2 D4 G I3 D2 P" K5 E ask turtles [ set-car-speed ]2 r" M- h' C: N
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reset-ticks
9 L1 g* A" U( f: ]4 t5 Eend
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;; Initialize the global variables to appropriate values
! V7 D, K0 X' I- n) ^$ P9 M9 H. }2 Sto setup-globals
3 m$ ?* p3 `- R; u6 K, K* v set current-light nobody ;; just for now, since there are no lights yet- v8 ^. p Z' `7 F6 k( m! X: d* H& n
set phase 0
) q. p% B# z4 }2 ^8 g: d, t1 U) P set num-cars-stopped 0
% g3 w+ o6 l" s1 ] set grid-x-inc world-width / grid-size-x
- u/ E1 v; H+ Z! Y: _0 V8 ~ set grid-y-inc world-height / grid-size-y( u. o- O" L2 }( u5 z
3 Y- ^- y' Q3 J x; h ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary1 q% _' I! |* k. \. ~' C& ]
set acceleration 0.099( @& A; H* W0 F/ ?4 K& h
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,! [+ V+ j9 |& C/ r
;; and initialize the traffic lights to one setting
: @* Z) b9 N) @2 i. n6 Sto setup-patches' p% T) N% V: W- y* \
;; initialize the patch-owned variables and color the patches to a base-color
& j% i/ `6 w* k' S; K; s% n ask patches
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set intersection? false* n: T7 c- L" b- h3 x3 a l4 j8 S
set auto? false
$ E6 g) X- q- f- o4 _, C' N3 k! A set green-light-up? true
. N; {* n- q, ^/ R set my-row -1
/ ~9 `3 @/ H& O0 c set my-column -1. Y+ R$ S7 l! b% e9 E/ l9 `" d4 V
set my-phase -1
# B+ X" x/ p1 _6 @+ S7 t) L# e \1 \, e. H set pcolor brown + 33 O+ ^1 q+ r0 B9 h. i4 o- U
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;; initialize the global variables that hold patch agentsets
* t% D- K; d$ X3 S& e set roads patches with$ f7 E7 g6 K) Z9 I+ w
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
& ]' u# S) x5 Z1 u. K1 Z1 m (floor((pycor + max-pycor) mod grid-y-inc) = 0)]4 H+ Y& ]8 ?! k0 x2 I' \5 w1 D* j
set intersections roads with X6 l* s$ x. N3 `# `6 ]3 u
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
# y; A" ?# L$ f# I) y$ Y) Q (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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4 f- V2 e) K; |0 h7 p, G ask roads [ set pcolor white ]
! \7 G. U9 `1 R( J ?0 w setup-intersections
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其中定义道路的句子,如下所示,是什么意思啊?
4 H/ g6 H' |. C2 d set roads patches with0 r5 \9 A" x, l
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
2 S2 M+ v% N( X. B2 w (floor((pycor + max-pycor) mod grid-y-inc) = 0)]. V2 {( H& A. X$ B( i% 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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