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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。+ Q% B$ K: G( G* z+ @! u$ A' t0 ?
netlogo自带的social science--traffic grid这一例子当中,
! ~! `% R* Q/ j5 E7 s, pglobals: k; Y) ~/ d! n* F+ S7 f8 T
[
5 V6 P# G4 F. {2 Q& o' g grid-x-inc ;; the amount of patches in between two roads in the x direction
$ D) C$ N) N. D) y9 _1 `( L6 J grid-y-inc ;; the amount of patches in between two roads in the y direction; K. q+ g, z, U- r+ C; T! v9 ?
acceleration ;; the constant that controls how much a car speeds up or slows down by if
* X \8 L+ C" }3 k1 S ;; it is to accelerate or decelerate) a8 B4 V! e; {% [: G
phase ;; keeps track of the phase
, z0 x8 X4 S0 ? num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
( q2 i4 I( J M$ `; J current-light ;; the currently selected light
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;; patch agentsets
3 V2 `0 O1 C( u5 E8 E intersections ;; agentset containing the patches that are intersections0 V& L5 @/ D5 t8 m7 K2 n9 v
roads ;; agentset containing the patches that are roads
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turtles-own9 b) N! ?& n; u1 s& A
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( f) a+ Q. \( C9 K2 E speed ;; the speed of the turtle" z9 T; z8 H9 ?# X; _7 T9 ^& |9 }
up-car? ;; true if the turtle moves downwards and false if it moves to the right
7 S6 Y0 Y# y. p m" g wait-time ;; the amount of time since the last time a turtle has moved
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8 p, ]1 d1 v- w2 f( spatches-own
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intersection? ;; true if the patch is at the intersection of two roads; m5 j& b+ h, A: r! Y
green-light-up? ;; true if the green light is above the intersection. otherwise, false.8 I7 ^9 m, |3 ~! F; x% Z
;; false for a non-intersection patches.
' y# b2 a' E3 Z- a0 h; [, F/ D7 s+ U: { my-row ;; the row of the intersection counting from the upper left corner of the0 d" L) y$ G4 i/ L: d- [2 M
;; world. -1 for non-intersection patches.
9 [* j+ c& w9 ^/ D" w, E my-column ;; the column of the intersection counting from the upper left corner of the% x0 x0 z. T: l! K6 z- ^
;; world. -1 for non-intersection patches.
% L i% ~! E; N* U3 [ my-phase ;; the phase for the intersection. -1 for non-intersection patches.* I7 A! i. i9 _% {6 }# s- }
auto? ;; whether or not this intersection will switch automatically.
- g3 n! Y* l0 F) B0 p$ B! z ;; false for non-intersection patches.3 c0 B, C' D4 B- z# K1 Z
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;;;;;;;;;;;;;;;;;;;;;;
# l5 H6 D) w8 `& }" a# Y;; Setup Procedures ;;
3 B' X' V1 W7 g7 @& D6 |;;;;;;;;;;;;;;;;;;;;;;4 m9 M$ a5 f4 {( C* a$ Z1 @/ d7 `) Q
' L) q5 g/ I; U: A( P- s) n* n% L;; Initialize the display by giving the global and patch variables initial values.4 B+ ^$ o5 t% E
;; Create num-cars of turtles if there are enough road patches for one turtle to% A( ?# b, H9 T5 y) r
;; be created per road patch. Set up the plots.
; c( U" a; f7 Y" Eto setup2 p) ?' @! Q; V6 a. P
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setup-globals
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;; First we ask the patches to draw themselves and set up a few variables
( [, d6 Q0 _. k; q/ p setup-patches
- K( ~8 ^- |, B. V7 n make-current one-of intersections
& _" ~3 q( n; ` label-current
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set-default-shape turtles "car", s/ `" y' r( ^2 i% H" [+ n3 @" }
3 I4 E# P4 {/ T" c* f if (num-cars > count roads)
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8 B. q: }* Z: J: D! ?/ o: i user-message (word "There are too many cars for the amount of "
- g. J% C# a5 ?2 {1 L. h "road. Either increase the amount of roads "
* F) K0 C. ?3 ^ "by increasing the GRID-SIZE-X or "4 @1 g7 R1 n% F# M5 D# Q
"GRID-SIZE-Y sliders, or decrease the "8 q/ G) N- M/ @2 N/ J7 W/ B2 ^
"number of cars by lowering the NUMBER slider.\n"1 E. L2 m" T+ P: H' ]6 l
"The setup has stopped.")3 K0 T. ~2 k, A! v
stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
4 ]8 {+ m2 n. G$ O E5 W8 ?! m0 N crt num-cars
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: j9 A1 O/ O" t setup-cars
7 W6 ^' Y, q6 |, B# E! E1 H% R set-car-color8 \4 S+ d8 l) a6 S( S& m7 K& V) m2 A
record-data
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5 `. h+ ]9 M1 J2 ]# e3 x ;; give the turtles an initial speed; T( B4 n5 N. e2 N7 p& N
ask turtles [ set-car-speed ]( h- p9 ?7 d( V4 i: l7 ]
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reset-ticks W9 U5 I3 S; ?( y$ s7 H
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;; Initialize the global variables to appropriate values) H- P4 V$ |$ V" o S% h# S
to setup-globals- i- L, z% ?) d" }* R6 ^
set current-light nobody ;; just for now, since there are no lights yet' x4 f8 H' }. T5 K
set phase 0
, ?$ _7 W' L+ N1 o- P( M z7 M" j set num-cars-stopped 0
% @6 s! W) t% W% o% D- O set grid-x-inc world-width / grid-size-x0 l6 ?' @" `' U
set grid-y-inc world-height / grid-size-y
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary6 ?/ V) ^5 E2 J* x! c8 ~0 a- d
set acceleration 0.099
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; N G9 p2 P) k+ W/ O' G# A, @;; Make the patches have appropriate colors, set up the roads and intersections agentsets,) \( A/ y! \% m4 ]0 P+ q
;; and initialize the traffic lights to one setting
, L: Z2 l! q% u% b/ \to setup-patches
& d; e& b! c. [* E4 l1 q" q6 J8 }5 l ;; initialize the patch-owned variables and color the patches to a base-color
, L- K. J$ l5 s4 x; \" H ask patches
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4 z! m3 P! y' g* i set intersection? false
: W( b j% w3 W. O k* C- i; C% { Z set auto? false
' X; X P) S8 \2 e# F set green-light-up? true3 o) O" f% a" s/ w
set my-row -1& k. |. X- O5 a2 a, H8 G, S; g
set my-column -1
' y" k4 c$ L" d3 w2 V set my-phase -1
' N8 ]: \+ ]/ |, S& H set pcolor brown + 3
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2 }: d+ s$ O U0 u+ n j" S E4 C T ;; initialize the global variables that hold patch agentsets
2 Z* O0 M4 b9 K6 y" [$ K# X set roads patches with7 ^1 w/ ^7 |0 r( Y, g' Q
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or c0 M# }6 ^& T3 r( ~. a1 Y, \9 `
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
1 @4 K, x8 X! }5 q set intersections roads with# }& ~& W) n- q% g" A" L2 B
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
. j) }: _) \! H3 m (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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+ k6 u$ Q; N# y ask roads [ set pcolor white ]/ X: u/ S8 W) R$ C
setup-intersections
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其中定义道路的句子,如下所示,是什么意思啊?5 J* V1 }/ i& y# Y J1 g* M
set roads patches with
. D+ _- g$ T8 [4 x' g [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
# @3 M {6 ^; p9 I( a0 M (floor((pycor + max-pycor) mod grid-y-inc) = 0)]8 @: ]! I; ~7 \) 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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