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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。) H7 y, h2 B7 V( H. E
netlogo自带的social science--traffic grid这一例子当中,! _4 N' d/ @0 H2 `# H8 d
globals
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. ?2 i1 @5 B& C8 A$ e grid-x-inc ;; the amount of patches in between two roads in the x direction
j; L. O/ F' T* d( l grid-y-inc ;; the amount of patches in between two roads in the y direction: O& g# b( s7 {6 Y/ ^% ?
acceleration ;; the constant that controls how much a car speeds up or slows down by if6 e& F- m8 r( l! J& m* t4 k' k
;; it is to accelerate or decelerate
8 A% }, p& O" w) j phase ;; keeps track of the phase
7 o. ^; H* C5 n1 H num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
. [/ N3 A4 F9 I; [ current-light ;; the currently selected light
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! f6 D' E( p* k9 ^0 f ;; patch agentsets& G' S2 s' x+ v2 C- n" O
intersections ;; agentset containing the patches that are intersections( l9 j1 [/ r9 `) w
roads ;; agentset containing the patches that are roads) P( v; t2 d( W7 I2 ?+ V6 b
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0 [+ N0 j- l, n0 z6 o8 Vturtles-own' p- J3 M) ^9 x
[
! y7 r& ^6 g% u' ?8 u speed ;; the speed of the turtle# j- _5 |" Q" s3 m# y3 e
up-car? ;; true if the turtle moves downwards and false if it moves to the right; d& C) P. x6 }8 ~1 A
wait-time ;; the amount of time since the last time a turtle has moved
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7 m) G- a3 A& x9 y" \1 j1 B/ hpatches-own
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; c: m w1 \2 T intersection? ;; true if the patch is at the intersection of two roads- v# B5 w. F# _
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
1 F0 m" c9 \3 d" V9 z ;; false for a non-intersection patches.0 c+ C& M/ Q6 V" P' A
my-row ;; the row of the intersection counting from the upper left corner of the
% W! r3 E. a- E" f9 X ;; world. -1 for non-intersection patches.
* q+ V. s& |: |& U. Y( M# g my-column ;; the column of the intersection counting from the upper left corner of the. M$ `* B5 Z+ B8 A/ G; M
;; world. -1 for non-intersection patches." r ], A% D o+ {1 i0 e: p
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
, I' s# E6 F. H& t1 w) ?6 @ auto? ;; whether or not this intersection will switch automatically.1 ]/ v% H, M$ x/ s* X
;; false for non-intersection patches.
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. j% ^) L I, p0 I' |7 ];;;;;;;;;;;;;;;;;;;;;;
: K9 `0 q* p# ]3 [) b# t& A% Q" S;; Setup Procedures ;;
$ o; g4 d t/ t0 @) Y0 B8 g;;;;;;;;;;;;;;;;;;;;;;
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- }- i/ \& S' r% g;; Initialize the display by giving the global and patch variables initial values.( \' a S! y( t4 {$ O. g. r
;; Create num-cars of turtles if there are enough road patches for one turtle to
6 F3 l U- ? y. S! @;; be created per road patch. Set up the plots.
1 a2 s5 W7 ?! s* P% ^( i: w* Bto setup9 s4 h! F4 \9 a! m/ O7 x* ?
ca
9 ?" o6 k9 G7 Y$ x& Z setup-globals
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* _1 P, r. D' ?5 k) W ;; First we ask the patches to draw themselves and set up a few variables
- s- `1 p7 V8 ~ B" m% I% u1 ` setup-patches
e, z; S0 b) h2 P1 I8 d5 ?6 Q make-current one-of intersections
! e* q. d U: h label-current
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set-default-shape turtles "car"- {: c' ^: U: j5 Y9 _$ x- @7 t @
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if (num-cars > count roads)
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7 s9 B5 M' v6 y# Y* ] user-message (word "There are too many cars for the amount of "6 w* q/ o& D* q z* v4 l
"road. Either increase the amount of roads "
4 v# }+ C7 t6 y2 |# k. b3 j8 x "by increasing the GRID-SIZE-X or "
& m& [6 R3 c6 C9 A+ l8 Q "GRID-SIZE-Y sliders, or decrease the "8 I) ?3 U5 M+ k/ ~2 b( {
"number of cars by lowering the NUMBER slider.\n"5 r, {* O4 M- Y' @. a
"The setup has stopped.")! Q, P* m! _! X" w. K2 p
stop" e1 G5 n1 O7 G1 e% p
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3 b, [/ h8 r" h4 | G% I ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
! N; k: f3 ]% ~4 |; I3 u G crt num-cars# h# e2 e9 v6 m& T6 \
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set-car-color
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5 s5 E/ Q# `+ G3 T7 J# k ;; give the turtles an initial speed
# I. B8 i. y. ~ ask turtles [ set-car-speed ]% C! r' S, V$ F. Q8 B
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reset-ticks f4 Z+ [3 ]8 O+ x
end
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6 P5 f9 g" V" \% ]. ];; Initialize the global variables to appropriate values% k8 S% Z" {) ^4 h+ F5 H1 s6 W
to setup-globals
1 ~3 v' g6 Z# }$ i5 y set current-light nobody ;; just for now, since there are no lights yet
( [+ I4 j) b- }* ~( m: W' Y5 g1 K: `3 r set phase 0* K0 _6 Z, Y1 y
set num-cars-stopped 0
% a0 S, A$ @3 Z5 D set grid-x-inc world-width / grid-size-x
9 S) c _4 D# w( g( z: l4 c c4 ? set grid-y-inc world-height / grid-size-y u1 |8 B7 r9 K+ h/ ?
) Q* k! |1 O3 ?3 {/ p1 o ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary( F3 x6 b7 T* T. D. L8 K
set acceleration 0.099
& M3 V$ D5 B; d& T7 F% y; rend
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,3 d( H" b: Q5 @( V1 E
;; and initialize the traffic lights to one setting+ H) R, a1 F! [* a4 u, j
to setup-patches n2 A1 o) W# k/ p
;; initialize the patch-owned variables and color the patches to a base-color6 B: P0 C2 B% N$ {$ g; S8 a
ask patches
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5 G( F( V* d+ \% _9 f set intersection? false: z& ~. H& ^8 q4 F6 V1 A
set auto? false
' J# f1 k. s8 | set green-light-up? true
2 H5 p5 N% Q v, a* n3 E9 } set my-row -1
) n9 _6 C$ L/ D5 u set my-column -1' _+ T+ \" u6 n
set my-phase -17 Q7 Z- l. H; @4 R
set pcolor brown + 3
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T1 i8 S; }7 K1 \ ;; initialize the global variables that hold patch agentsets
4 O- F! Z/ G/ m5 w set roads patches with, n. V) m" |' Y7 F/ R3 o
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
7 {0 I. U: b( t' A5 O! M4 o (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
% R8 R3 X, U/ I5 f& b set intersections roads with7 F; ~% X& `! |: K, D$ S
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and6 K1 {8 u- }+ v# Y
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]5 y/ V( @7 s( _2 ?! L3 d
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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?$ L" E U. M/ s) `8 r
set roads patches with: L( G$ Z' o3 Y' W1 k. U
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or% D9 v" B1 q) p# n0 e4 g- F! N) Z. @: I
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
& u1 Z7 v1 X. m2 F2 ?, F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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