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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。7 j* U$ Z3 y0 |5 E. B' i
netlogo自带的social science--traffic grid这一例子当中,. w/ k2 x; |6 b: F7 Y. Q
globals
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# p8 e8 B T# d$ ^' x0 o* H! R grid-x-inc ;; the amount of patches in between two roads in the x direction8 o3 Q- Y0 w0 P8 Y' d0 t' I3 `
grid-y-inc ;; the amount of patches in between two roads in the y direction
7 V! R4 e. o8 q% p( y8 q9 ^ acceleration ;; the constant that controls how much a car speeds up or slows down by if. c8 \ [( m2 O
;; it is to accelerate or decelerate+ p4 A: x% ?4 m' s3 v, t
phase ;; keeps track of the phase. n M# O0 j; z6 c
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure. [" q: I* W8 H6 p- l7 _, [
current-light ;; the currently selected light2 P9 f! W- `& |$ b
0 Q; t7 R5 d% _2 T* g* A ;; patch agentsets, W% D( x. i$ Q: K" {" T
intersections ;; agentset containing the patches that are intersections- @, S0 U7 `2 s/ q2 d9 b+ U
roads ;; agentset containing the patches that are roads
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turtles-own4 S! M0 t% d+ s/ y5 j7 r
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speed ;; the speed of the turtle
5 M/ i9 e) x1 `* `' r0 f up-car? ;; true if the turtle moves downwards and false if it moves to the right
1 |! D$ W t7 H. l wait-time ;; the amount of time since the last time a turtle has moved6 u4 f6 o2 ~8 f
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; c& G8 z; C$ Rpatches-own0 d/ D) w Y+ X, f
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intersection? ;; true if the patch is at the intersection of two roads
# F6 @7 C' G* C: R green-light-up? ;; true if the green light is above the intersection. otherwise, false.
% l: s) P8 z% D- ?2 v4 a$ m8 }* i ;; false for a non-intersection patches.
" [2 N1 J' |6 A" W; s- c" j; Q, h( Q2 Q my-row ;; the row of the intersection counting from the upper left corner of the
8 ?4 x& x) N8 c0 U ;; world. -1 for non-intersection patches., a2 B6 a, o+ S4 ~( f5 M( ?- ^- _
my-column ;; the column of the intersection counting from the upper left corner of the+ f7 Q6 o7 e2 H% B. r
;; world. -1 for non-intersection patches.
4 E% ?* y8 p7 U0 b my-phase ;; the phase for the intersection. -1 for non-intersection patches.
" L( w; O$ Y8 |2 t auto? ;; whether or not this intersection will switch automatically.
" U- B6 r! u$ X4 w3 b+ O ;; false for non-intersection patches.1 L8 C+ t# Q/ v
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;;;;;;;;;;;;;;;;;;;;;;( Y9 ]7 D+ s! e! j& N! l* T) A
;; Setup Procedures ;;
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;; Initialize the display by giving the global and patch variables initial values.2 E. y4 X1 M: d* E3 j
;; Create num-cars of turtles if there are enough road patches for one turtle to
1 Q, D1 i& h6 c: M/ Q% ^. \$ L;; be created per road patch. Set up the plots.
( ]6 |: Q7 R$ N2 kto setup
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. }9 b( ]/ O' d2 k* ` setup-globals" A7 f! r2 J# N" v" P
- e7 E4 o- }: n3 f' I: l: m$ j ;; First we ask the patches to draw themselves and set up a few variables; m8 |0 [: S0 o/ d
setup-patches a V5 L+ Z5 F5 Q
make-current one-of intersections
I ?3 [$ R7 F+ N label-current
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set-default-shape turtles "car"
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if (num-cars > count roads)5 d3 k' h- j' [5 k
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2 k# [3 P9 w+ K1 j: I) N9 N; ` user-message (word "There are too many cars for the amount of "& r. h2 \$ K9 p$ b: G8 I
"road. Either increase the amount of roads "
# `7 Z* w7 v N5 P X "by increasing the GRID-SIZE-X or "
4 w' p" {3 z$ r0 _8 T. E, f! [* ] "GRID-SIZE-Y sliders, or decrease the "3 I: e& @3 {" o% [6 V. t' m
"number of cars by lowering the NUMBER slider.\n"
" y/ s. T3 `* W" w% n' \ y g; G" g "The setup has stopped.")
+ k$ E6 @: j; l: R+ ~ stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
2 v' S5 y" w: c) ?8 k1 X crt num-cars
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setup-cars
2 I% d8 b4 z% V W# Q set-car-color
, [4 T8 g$ X6 b* Y. a. b record-data v5 |0 A8 o- F" Q Y
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( W' B9 o! W8 h, e ;; give the turtles an initial speed
, n( I) P/ A( X$ @& O% P7 Z ask turtles [ set-car-speed ]" M/ v5 F) V- Y! c- @- k
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reset-ticks, C/ a% {" J& @" R, t8 G5 ^' Q
end
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;; Initialize the global variables to appropriate values! x, t% t/ O- {5 }3 A5 ?
to setup-globals
$ i: u1 j w& \( C# q* y5 `, o set current-light nobody ;; just for now, since there are no lights yet% g: Y: \2 O s; |8 u
set phase 0$ T! E7 m: Y; N
set num-cars-stopped 0/ G9 V% J6 E) z' L; X# h
set grid-x-inc world-width / grid-size-x
9 E0 B& n: _& a+ ]4 k 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 boundary
8 ?- k9 f' a: |8 y: H set acceleration 0.099
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
$ Z# |" P `) N;; and initialize the traffic lights to one setting
. R5 J( \4 F* h! \6 t) `to setup-patches
0 e7 I( ~6 n! K9 F% s+ L ;; initialize the patch-owned variables and color the patches to a base-color' b8 ?" s4 K( A4 L
ask patches
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set intersection? false& A' Q0 g. v5 ^+ S2 K7 G; ?6 G
set auto? false
; |' C" }& b/ G( _6 C# q( ]5 \ set green-light-up? true
- d; d% x8 U( X7 x set my-row -1
6 k0 c4 U2 A: @& y set my-column -1/ F2 g. z& q" r
set my-phase -1
; \: r. C; n* C' `# B% j s' d set pcolor brown + 3; w4 M- b c% |+ p* @
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; }* o4 d( N: e' y2 g& S ;; initialize the global variables that hold patch agentsets
( G6 T3 J( T# J4 E- x5 ~7 A set roads patches with
4 s* {% i/ I$ w8 E$ z# s [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or# Y) d5 I9 [0 C, g) k" G" N4 Q. J
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
; ^; S8 M8 R2 t' t Q- \ set intersections roads with
8 |$ B1 [7 p: g s [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
4 O( j! r7 m, c8 D1 x (floor((pycor + max-pycor) mod grid-y-inc) = 0)]5 N& R' {8 y* U; t) E2 ?1 |' ~) ?
, E r$ }: k5 W8 J% ^: k8 A+ ~ ask roads [ set pcolor white ]) B5 _9 X1 \$ P
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 w+ R2 p# x( n# L
set roads patches with
+ {9 ]/ Q! Y5 W& h [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or! l$ e" _+ C/ j* S' e
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]) y) Z1 m- V0 A
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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