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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。5 L$ r" C) Y( B! X4 n7 f
netlogo自带的social science--traffic grid这一例子当中,
& }2 D1 [3 t- U+ Nglobals
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9 r% t# b) @# f( r/ \/ V$ d grid-x-inc ;; the amount of patches in between two roads in the x direction
f% K- V0 U1 I* H. j. w: d, g grid-y-inc ;; the amount of patches in between two roads in the y direction
+ g D& b0 }3 q; N" g acceleration ;; the constant that controls how much a car speeds up or slows down by if6 S$ N4 S% K$ P! u5 g
;; it is to accelerate or decelerate+ _1 d4 c3 ~) O0 m
phase ;; keeps track of the phase
, @# z3 y6 e% R num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
$ t8 {: G1 d, g current-light ;; the currently selected light# J G' w a/ E% q' i1 v6 a: @
; T3 X/ |6 r. M/ \0 f& \ ;; patch agentsets" H1 ^# ^! I5 d+ Y$ K2 `* a' [
intersections ;; agentset containing the patches that are intersections# w+ R; D1 l3 p/ d7 W+ U- g5 i& t- a
roads ;; agentset containing the patches that are roads
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' \0 U' {1 q1 S5 ^turtles-own
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speed ;; the speed of the turtle4 C& Z/ `7 I9 }7 s Z$ h$ R
up-car? ;; true if the turtle moves downwards and false if it moves to the right
: ]; Z1 E' n6 H* G7 |0 d wait-time ;; the amount of time since the last time a turtle has moved! }4 n5 X6 b) L& ^ O. x6 E6 L
]
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads
1 }6 g3 I- B$ N! A; s' h; Z% U green-light-up? ;; true if the green light is above the intersection. otherwise, false.
5 V5 j+ q f! S4 g0 e% q ;; false for a non-intersection patches.+ f3 t& P3 S/ v3 B& H/ ^
my-row ;; the row of the intersection counting from the upper left corner of the+ n8 ?5 w! I1 u l% Z
;; world. -1 for non-intersection patches., _! Z1 g5 j4 x- {) v
my-column ;; the column of the intersection counting from the upper left corner of the
3 L& E% I* a1 |; ~# X ;; world. -1 for non-intersection patches.( @9 a' B) c. x9 v
my-phase ;; the phase for the intersection. -1 for non-intersection patches.! B& {# v7 P& P0 b' X
auto? ;; whether or not this intersection will switch automatically.
, ~: x" D; T' ?' { ;; false for non-intersection patches.7 J0 p& }; n& J3 s4 u; I8 s
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& N; z- O2 K5 Y6 {- l2 E;;;;;;;;;;;;;;;;;;;;;;
8 m8 y2 a% @7 H5 ]- @7 A& W* ~ n& j;; Setup Procedures ;;4 ^3 p; Z. O( z
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;; Initialize the display by giving the global and patch variables initial values.
+ R: J3 c8 F8 M' _2 M# |0 i* L' @;; Create num-cars of turtles if there are enough road patches for one turtle to
, I0 `- b' ?( g2 F& r6 w6 P;; be created per road patch. Set up the plots.( I/ }9 b2 o7 L3 c5 ~
to setup
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/ p# ^! K: X& U( Q6 [% ?. _8 p setup-globals- R0 Z" A% c& P/ }
: t! Z: `9 b t9 ?3 G+ D ;; First we ask the patches to draw themselves and set up a few variables
% F+ p/ F( e+ _9 G3 R setup-patches
! D! U* z; }2 h) m7 t make-current one-of intersections
* V- P4 L5 X) p* o3 D5 P& i label-current
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set-default-shape turtles "car"
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if (num-cars > count roads) j2 l% P6 X9 ^6 i9 J
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- x' e) K$ I" R0 k. w* i user-message (word "There are too many cars for the amount of "
5 n( p& M) q9 R# \ "road. Either increase the amount of roads "
; p/ G/ M" _+ e i( B9 `1 R" y "by increasing the GRID-SIZE-X or "
+ z# ?1 B$ m1 k1 t! R, ?$ W "GRID-SIZE-Y sliders, or decrease the "
, V3 D- p5 U: C- p/ s "number of cars by lowering the NUMBER slider.\n"
- a7 s9 @, q0 z9 m: w7 Q "The setup has stopped.")
0 \0 s7 C R4 g9 P; P' [: w stop& M0 v* _! y1 {# d0 D
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
* o# C8 O# R0 ]# Z6 z/ m6 _ crt num-cars. p/ b, _' q/ V5 d
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6 |9 X L( b4 s1 s! p! e setup-cars
h# u. o9 h' v: D' x. R4 {6 ^" F set-car-color5 T/ e- G/ |; x! C( t# B
record-data
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/ D/ u9 [6 q( v ;; give the turtles an initial speed
5 Y3 [( b) S# |0 J ask turtles [ set-car-speed ]
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reset-ticks1 P- m4 e& C% U" U9 i; h# @0 q
end2 J8 @7 U# Y2 p
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;; Initialize the global variables to appropriate values. r! u9 d6 F+ O! J
to setup-globals% p; ^/ x! t! _; ~
set current-light nobody ;; just for now, since there are no lights yet
3 z1 g# k/ T# f/ V set phase 0 j0 \- A0 N. R; B& x( p* ^
set num-cars-stopped 0
0 P5 d4 j- P! `; F- X( J set grid-x-inc world-width / grid-size-x
; W, D7 W+ f9 _$ _4 |! s set grid-y-inc world-height / grid-size-y
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/ I' F% [' e( K ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary: L' @- p1 P5 l- q/ p1 `& a6 _
set acceleration 0.099
* |7 l8 V# j# ^. P& k( ?end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
# u( z$ m; s( c;; and initialize the traffic lights to one setting
; G. A5 i4 q* f" Pto setup-patches) i5 S; J) t, u8 i U
;; initialize the patch-owned variables and color the patches to a base-color6 H# y8 s2 c+ Y ?7 B% e5 z/ x
ask patches" h+ W8 B+ \) y! ~2 m+ o% q6 w
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set intersection? false' h5 L/ {3 m3 |3 ^' d7 _
set auto? false& f* e9 M6 ?9 O/ ^: h# Z
set green-light-up? true
8 H0 b0 K, g: L4 f) C set my-row -1
8 X8 u% {* {$ b9 u set my-column -1
5 d( p) B! s2 Y7 R- S1 {2 \ d set my-phase -13 P1 u. k; u2 _ G. ^- @) h
set pcolor brown + 3! i8 x; O, b9 L# }9 y+ c' J
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1 |* q' Y. j* A7 [- l! f ;; initialize the global variables that hold patch agentsets
; x; L5 r" M# [ set roads patches with& }6 m- P2 T U6 t1 M2 M
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
, P- ?1 k0 I) T6 s0 s3 s (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
$ M9 A0 @/ x. R& h1 F. v set intersections roads with
z; P. M5 |, k [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and7 W }# A- O0 C) N% P
(floor((pycor + max-pycor) mod grid-y-inc) = 0)] l- {* @7 v. F+ H/ E' @6 Y3 p9 X
# M" c5 b7 c( a* z! j( ?9 n* ` 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?
; F1 o9 a4 r7 G8 L N# y* h set roads patches with
2 O5 [1 G4 \6 }& D0 h" |8 ? [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or+ t3 u- J8 H% G) x$ J. p1 o) P
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
, |3 h2 M1 R' d6 a% T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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