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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。& E( P/ j, z3 B7 g
netlogo自带的social science--traffic grid这一例子当中,
F" k5 d. v: X, M. J( Pglobals. P3 D( o0 ?. o) R
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grid-x-inc ;; the amount of patches in between two roads in the x direction; |0 G7 p, X7 U# @2 R
grid-y-inc ;; the amount of patches in between two roads in the y direction9 J' l6 W0 p( j2 v0 S. p3 j
acceleration ;; the constant that controls how much a car speeds up or slows down by if4 z! u; J2 v+ \' w. ?. c+ P3 C
;; it is to accelerate or decelerate
$ V' Y7 Q& g7 R; v- Q% P, b8 c phase ;; keeps track of the phase4 H0 U" v7 ~0 `
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure. I) h/ G4 H- |
current-light ;; the currently selected light0 l( b3 j# U" p3 p& l- g% B
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;; patch agentsets- r: N. _5 P5 D! ~6 o, P) `
intersections ;; agentset containing the patches that are intersections
0 ^/ \. y8 _5 A roads ;; agentset containing the patches that are roads' z3 s* ?1 _. M- Z+ c* a
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turtles-own
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1 i- B4 x+ Y) }$ F speed ;; the speed of the turtle
8 s& V3 L6 s. h$ B up-car? ;; true if the turtle moves downwards and false if it moves to the right
, l$ S" \& j# D& r$ n" U wait-time ;; the amount of time since the last time a turtle has moved
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patches-own# J/ ~0 M* c3 Z, F2 c) J
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8 L U. }( J3 R0 [ intersection? ;; true if the patch is at the intersection of two roads
+ e2 E1 M9 L+ t! t- ^. h green-light-up? ;; true if the green light is above the intersection. otherwise, false.0 |$ Z; k, l: V( f5 r
;; false for a non-intersection patches.$ J8 ]# t: l3 V+ j+ h
my-row ;; the row of the intersection counting from the upper left corner of the
N0 }9 r- C. q" t; [" Q6 i ;; world. -1 for non-intersection patches.( i1 A! @7 F% ?, Q# w8 h
my-column ;; the column of the intersection counting from the upper left corner of the
' M# g! r& p0 {6 o! L, W { ;; world. -1 for non-intersection patches.1 O# V! p' M+ ?5 ~' u
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
+ M9 s7 i4 }4 y auto? ;; whether or not this intersection will switch automatically.
0 s8 ^; Q" }/ D% L# J. r ;; false for non-intersection patches.! C& d4 j$ k8 x0 `$ T5 R" w- I
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/ Y" H1 ? K4 W+ f8 {! c7 s% X;;;;;;;;;;;;;;;;;;;;;;8 F- a7 k. \! D& Z4 w' Y' H4 r0 D
;; Setup Procedures ;;
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;; Initialize the display by giving the global and patch variables initial values.
9 r- O' \4 z4 U) V: K;; Create num-cars of turtles if there are enough road patches for one turtle to/ A" ?' [) `: w) P+ W
;; be created per road patch. Set up the plots.' S1 ]" c% ^* a3 E1 Q
to setup4 u% ?0 _% {, d( w3 g$ p. Y
ca
! _ e6 k z2 \8 z setup-globals
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;; First we ask the patches to draw themselves and set up a few variables
" f9 l6 c5 g6 x setup-patches
5 _' D z& g- W1 k+ G make-current one-of intersections
4 k: G. b2 ]! D! v( H$ Y0 [0 } label-current
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set-default-shape turtles "car"
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if (num-cars > count roads)
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7 m- B5 q5 H- \" U7 \" V user-message (word "There are too many cars for the amount of "
& K8 @3 c* o/ p "road. Either increase the amount of roads "
$ I. i( i# o) {4 H8 W5 s "by increasing the GRID-SIZE-X or "
& ?7 H- ?8 m2 T8 ?, M "GRID-SIZE-Y sliders, or decrease the "0 l* y) E; x8 {4 C$ @$ A2 D9 S/ i
"number of cars by lowering the NUMBER slider.\n"0 g0 @4 X0 M# I$ l& v
"The setup has stopped.") {$ T' a# Y0 M3 w8 V' S
stop
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. F7 y3 Q4 K( {6 ~% R) I) [9 \ ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color& U3 Q) ~: T! N
crt num-cars' e+ L' a y' e2 W
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setup-cars
5 w) E1 z, ~. n( F1 \7 c4 i" L set-car-color
4 s8 L$ o: M, H: L3 G record-data! c1 ^$ F/ X3 [; v! t- E7 I
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;; give the turtles an initial speed" T* C* i4 e- ~" G
ask turtles [ set-car-speed ]: B3 {3 c3 N# P( P9 f0 o
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reset-ticks
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, t( T( }0 Q3 Q6 l;; Initialize the global variables to appropriate values
9 o1 @. X& Y: ^$ _to setup-globals
6 |# D6 Z7 D8 B1 u6 c set current-light nobody ;; just for now, since there are no lights yet
% q3 }) ^) @# b set phase 07 j& A8 f% S- V, z8 m4 v
set num-cars-stopped 0
9 P* G: v. G% m9 |: f0 p1 U set grid-x-inc world-width / grid-size-x. |- `! ^" M- `) T% n$ u4 A4 d
set grid-y-inc world-height / grid-size-y
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6 J; f+ M5 J9 h4 r) f ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
" u* Z3 r( q1 N( N9 O set acceleration 0.099
( [4 S5 g# Z, Z) @end/ x5 X. K& ~/ K6 n
9 L/ S! N4 F# k9 O;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
8 y" l5 b2 G! k- U;; and initialize the traffic lights to one setting" ?& ~2 G& y& \: o+ U
to setup-patches
4 F x y: g/ [* b5 F ;; initialize the patch-owned variables and color the patches to a base-color
% i) [. K+ T5 q+ ?! v. Y ask patches. j4 w! r% u" W( Q5 l; l3 ~. _( _
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set intersection? false
- K5 P) g( r7 i3 d. E9 [3 | } set auto? false5 V# P9 ]/ O/ ]! T) X
set green-light-up? true0 F+ M0 t4 @" R6 l; @5 H2 H* o
set my-row -1
2 x' T6 F4 D, c' _ set my-column -12 v) a0 e* W( m; {
set my-phase -1( ~ J% e; W3 A
set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets
& | m$ O* d/ S. A, Z set roads patches with
; [; a+ v& [( Z0 ]( N( q [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or5 f0 K+ N! m, T( Q" [
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]5 [ b9 q9 R5 S
set intersections roads with7 ?0 a' g; }2 C3 r& N' g0 U
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and# t* w9 i: _1 W6 i& \/ n! s( \' d
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]0 f! ^: b# A, Q8 d* j0 C
setup-intersections
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5 x. W2 Q) [+ _2 t- ~# g其中定义道路的句子,如下所示,是什么意思啊?
" M, T% p1 s) ? set roads patches with) M# z/ i2 e# i3 {
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or$ Y0 `5 L/ y8 l
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
* |# C# L4 X" Z- m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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