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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。. [2 v2 h- d9 Q
netlogo自带的social science--traffic grid这一例子当中,
+ u* r5 q- G# k; k4 m oglobals
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3 K+ c, I b/ I& I grid-x-inc ;; the amount of patches in between two roads in the x direction
2 J0 y& N) K* E U0 \+ i$ } grid-y-inc ;; the amount of patches in between two roads in the y direction
3 T$ V& C' Q+ s$ x p acceleration ;; the constant that controls how much a car speeds up or slows down by if
! d& |" F# Y( Z9 A7 s# y. j- n9 } ;; it is to accelerate or decelerate
8 u, A8 ~. G$ R* \ phase ;; keeps track of the phase
7 z9 {8 P# [# j* I% h1 T5 ?. a num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure; _! V: x; }3 {; J0 ^+ S! E
current-light ;; the currently selected light* J$ ~* P4 c1 s
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;; patch agentsets: _8 [0 `6 [+ v9 j2 E0 r
intersections ;; agentset containing the patches that are intersections- R B6 h6 m4 r
roads ;; agentset containing the patches that are roads
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turtles-own7 A: m* j; y1 q' i0 X5 U
[
+ h. ?/ O3 q$ A: w" ~ speed ;; the speed of the turtle1 _) [# R7 H: q7 j; J% W9 _
up-car? ;; true if the turtle moves downwards and false if it moves to the right
4 x' T: ]# q& S7 B0 F% Z. P+ t- A wait-time ;; the amount of time since the last time a turtle has moved+ e% D4 t* `; Q2 z% W. x2 w
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patches-own+ B5 X9 T3 V7 O: m2 `1 l( l
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intersection? ;; true if the patch is at the intersection of two roads6 l: W U- m7 e7 p6 q
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
4 }; x7 K" ~! q- _5 R8 d ;; false for a non-intersection patches.
# N' I% b1 D' [- t6 o n& q my-row ;; the row of the intersection counting from the upper left corner of the4 L4 O% n3 {9 E4 [
;; world. -1 for non-intersection patches.
' _4 Y' N `% z2 f: t( d my-column ;; the column of the intersection counting from the upper left corner of the
& f6 C* m0 w) x7 J ;; world. -1 for non-intersection patches.
$ J( s' U: N' u' { my-phase ;; the phase for the intersection. -1 for non-intersection patches.! y# D6 ~; R( f) Q/ e( \
auto? ;; whether or not this intersection will switch automatically., V+ n5 }! D% F! ~7 l: v
;; false for non-intersection patches.
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, f5 B3 n1 ^. i' I* M! n8 G;;;;;;;;;;;;;;;;;;;;;;
! L' ^' q* N) p( m ?;; Setup Procedures ;;2 Q0 g/ h' O: N5 z9 [$ t, ^
;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.
* i! J# B5 O* a; f2 g2 Y! [;; Create num-cars of turtles if there are enough road patches for one turtle to
6 s6 O+ |" d {# k" A1 N- j;; be created per road patch. Set up the plots.
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setup-globals G& t% u7 M! X8 Y
3 J/ \/ s& l" H1 V" ?% c( F, ] ;; First we ask the patches to draw themselves and set up a few variables
3 T C( g6 W3 l( A setup-patches
- K p% z! O) \7 G: j4 A make-current one-of intersections
) X+ F* I9 R) k label-current
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set-default-shape turtles "car"# G" |7 O4 A& @. f( X5 a. G: J
- u. J$ \# g, }- w+ L+ V if (num-cars > count roads)* j, o6 ?8 ]) t! G {# U( \
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user-message (word "There are too many cars for the amount of "
5 ^# A: x6 H- @& t E% g "road. Either increase the amount of roads "
( S! h0 M5 I6 a3 } "by increasing the GRID-SIZE-X or "0 e/ @9 l8 q2 e+ D6 c
"GRID-SIZE-Y sliders, or decrease the "
% Q1 @( E) h, _$ ~% p# k "number of cars by lowering the NUMBER slider.\n"
: Z: d3 j, p/ O4 T- H "The setup has stopped.")
; g& j: o- Y3 o/ Q+ N stop
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/ i+ y. I, @- O. Z U: J ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color- B: P9 x1 j/ |& o3 U7 g8 o
crt num-cars% u6 ]+ T8 e" a
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4 T, A- Q& x8 S2 C setup-cars1 _) I& R# j' m F0 O
set-car-color
: j7 ~% J* _; E5 A8 \- q record-data$ f3 t6 N' O/ _1 g2 s
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# r" s U# I, l$ B$ E, ~7 D1 u* D( @ ;; give the turtles an initial speed
+ o7 x( o/ t* w( F! J ask turtles [ set-car-speed ]
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* @ S# J( X+ Y$ f0 |; R! C& | reset-ticks: J4 j* i, Z4 |9 W9 T3 R, n
end. b3 P J/ W$ ]
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;; Initialize the global variables to appropriate values& D) F% `6 h1 K) w$ }) [
to setup-globals
2 U4 {+ A$ b( n4 E+ G set current-light nobody ;; just for now, since there are no lights yet
5 x L* Y& N, Z) X set phase 02 t8 w o8 E* u
set num-cars-stopped 0& f! i0 t1 M, K |- P
set grid-x-inc world-width / grid-size-x
, {$ V* I: Q6 N/ V8 H0 N& T5 l set grid-y-inc world-height / grid-size-y
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% V: A" O6 D) l2 C" C) C1 n! }/ P1 d ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
* y4 j) _/ y2 L6 k set acceleration 0.099
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
6 h* R9 Z3 j' f6 m2 B3 a;; and initialize the traffic lights to one setting" X; h$ r% Y$ ~% K: R$ W
to setup-patches8 v5 \. u) ?: O( _+ l; q
;; initialize the patch-owned variables and color the patches to a base-color
$ e2 m8 i D" x" o$ g! Z! R ask patches* @( @- O& ^( D( @, c% J
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( @! k* ^4 R- y; n2 X set intersection? false4 D! c5 m6 K/ o( _9 w4 d
set auto? false
E+ [# I9 m4 d- R! z# J; M set green-light-up? true
4 s' `- h+ g. E1 j* X5 t# O0 K set my-row -1
" q6 f3 E5 |( ? set my-column -1& P- p% d0 c! q
set my-phase -1+ Z8 ^, Z) J& O, _- w
set pcolor brown + 38 g, O$ H& d- T6 ?* k5 `
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;; initialize the global variables that hold patch agentsets
- Y- V# Z! {. A3 I set roads patches with
/ I' a* b$ J$ h1 c- t [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or( |% G7 m N8 E
(floor((pycor + max-pycor) mod grid-y-inc) = 0)] S! d2 d+ z- c# j
set intersections roads with
8 `& M$ C' x( T$ K8 Y* g1 p1 { [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
( @6 L D. |. m4 g# q (floor((pycor + max-pycor) mod grid-y-inc) = 0)]+ A. o8 v9 N' e% ]
/ j! |! |) H* E- ]$ K ask roads [ set pcolor white ]
* A0 Z* e0 V" x6 \, n/ I- ]' T setup-intersections8 l4 n+ u) U: x/ K" @" o
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其中定义道路的句子,如下所示,是什么意思啊?* E- K$ T/ P4 _/ ?5 b3 }
set roads patches with
. o; F* p, Z( F' O# P6 U9 t9 H [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
: d$ U1 ~. f; M' v( J (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
! B( Y8 b7 i: A& p/ U9 ^ M* U9 g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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