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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。
i7 ?: |, a k* [9 b4 ]netlogo自带的social science--traffic grid这一例子当中,
8 G- p, F- V( E7 W$ a2 ^7 eglobals: l: F; M2 f4 B( g6 y! Z) ]3 p/ H5 p
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6 b: P8 j! s) p4 G& B8 B* A6 q grid-x-inc ;; the amount of patches in between two roads in the x direction
$ t7 E, \, N* E, O grid-y-inc ;; the amount of patches in between two roads in the y direction. G0 E) z% l: ^; |% T* p' V
acceleration ;; the constant that controls how much a car speeds up or slows down by if' q' M7 [0 H. h; V
;; it is to accelerate or decelerate
- b; |# w7 ^+ J# O phase ;; keeps track of the phase
I5 m6 Z/ I. ^4 w num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
# W# Q) f' ]2 d3 o' n! W: w current-light ;; the currently selected light8 ^3 }1 M3 i! g
1 y* N3 m# n2 Q* W& M" f ;; patch agentsets
3 N3 W1 X. r& s& @ intersections ;; agentset containing the patches that are intersections
/ S% g6 ]1 A/ s: @' `- P roads ;; agentset containing the patches that are roads$ {' C t3 e0 {% t# ?+ g2 o- ?2 |
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g8 g& [8 F: B% @6 B6 Wturtles-own) b* K( g/ S& h
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$ q! o/ H9 m B" d speed ;; the speed of the turtle
: u- R5 O9 Z. A up-car? ;; true if the turtle moves downwards and false if it moves to the right
+ T9 x# [; A& J$ M) m4 y wait-time ;; the amount of time since the last time a turtle has moved# q1 r0 D" }) |5 d1 u
]
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads! T+ Z& P7 R9 a; d6 D
green-light-up? ;; true if the green light is above the intersection. otherwise, false.3 m* G5 E4 z7 n3 e
;; false for a non-intersection patches.
, M$ {6 g( W" y my-row ;; the row of the intersection counting from the upper left corner of the1 f2 @5 q9 ?& `; r7 A! z
;; world. -1 for non-intersection patches.
/ R7 \. W. ~9 M my-column ;; the column of the intersection counting from the upper left corner of the
( Z z$ j' ]3 V% m$ q ;; world. -1 for non-intersection patches./ b( H8 a4 {$ u& O3 Z& G
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
$ c3 }; g$ {7 p) J/ n* V N auto? ;; whether or not this intersection will switch automatically./ L2 a7 L5 d ~ K7 Y$ \' u" w
;; false for non-intersection patches.
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7 Q) i7 I/ f; n! b5 [3 n;;;;;;;;;;;;;;;;;;;;;;' \2 Q0 @5 M/ F9 [
;; Setup Procedures ;;5 V1 c P) k* d5 Z* x
;;;;;;;;;;;;;;;;;;;;;;
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, } y' B' Z7 W4 ?( y$ E5 i;; Initialize the display by giving the global and patch variables initial values.
6 `2 s+ x8 x, t, j2 L; T;; Create num-cars of turtles if there are enough road patches for one turtle to
/ }% |+ p3 Q- l+ b" z;; be created per road patch. Set up the plots.5 @3 ^) S7 _( J4 i1 o& j
to setup2 T% I! Z* {$ `7 ]: i
ca
0 D9 i* V/ X2 {1 J; { setup-globals* A6 A8 x- K! z! @" m
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;; First we ask the patches to draw themselves and set up a few variables' b1 u. X) ?) a2 m, b9 s
setup-patches% L) t2 [+ K9 P8 Q
make-current one-of intersections
$ ~7 q5 t u$ Z label-current2 z% f7 @9 p( ?0 U
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set-default-shape turtles "car"
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m- n. ~: ~5 C5 H5 t1 t if (num-cars > count roads)+ u# x) D; O7 \! r! _6 f- m
[
9 T" h$ i) |2 A3 J user-message (word "There are too many cars for the amount of "
% y6 C+ z" [& E3 V$ N1 s% U. @: }, C "road. Either increase the amount of roads "* B4 _# I0 U: b! \8 O
"by increasing the GRID-SIZE-X or "5 f7 d; P- H' [: [
"GRID-SIZE-Y sliders, or decrease the "
/ [0 e% M% E: b$ {8 }8 S "number of cars by lowering the NUMBER slider.\n"
# y1 C8 U0 ]* W0 b4 u9 e "The setup has stopped.")$ p% V! v2 e8 @/ L4 G
stop) t& |4 C' M0 f/ H G
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# |2 M9 R( C: n1 ?! e ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color! [& x1 l. m1 E1 X B- ~2 K& D
crt num-cars
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" O' J- Y+ d; G: X$ W, ~" `3 Z' z setup-cars
; X& F" g& U* [! M set-car-color
6 R( k) Q0 @/ M7 a7 Z record-data% O3 m7 E% Y( ~# M
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5 x2 b1 N6 S% s1 Z ;; give the turtles an initial speed
- Q( R( P8 X/ e1 \ ask turtles [ set-car-speed ]
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0 ^9 A1 d0 J! @ y* ` reset-ticks6 L# c) [4 e( V; Y [1 m( `6 Q
end
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;; Initialize the global variables to appropriate values
: w! F+ y4 T4 F, Xto setup-globals
) d, u% y* l, ~. }. t set current-light nobody ;; just for now, since there are no lights yet
& d1 z7 N1 X" l6 ` set phase 0) ]& ~0 b0 r r, K3 z( k8 V3 D
set num-cars-stopped 0: t. b. l- G2 l
set grid-x-inc world-width / grid-size-x$ j! x/ [& [1 I8 O9 y
set grid-y-inc world-height / grid-size-y6 i6 L$ t: j% W6 `
+ p0 a) Y& ~. y& T6 D& X+ ]
;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary0 c& f+ O8 m1 k( i
set acceleration 0.099, K! L5 [9 l, I L
end
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2 g5 v/ y5 l/ \9 `5 q6 r" [;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
1 \( t4 T1 m6 B% e;; and initialize the traffic lights to one setting
; G$ e$ c2 @) Z" I4 a& P" @to setup-patches
/ u& D+ f7 k) F" M ;; initialize the patch-owned variables and color the patches to a base-color
/ [' X& a7 f3 E+ Z; G( } ask patches
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. K' R- Q- T" P7 U set intersection? false
$ X8 Y' N# [& e' `3 m set auto? false) C2 `! t! o: o7 g, t
set green-light-up? true6 P4 D2 w( F# N; M3 j
set my-row -1
0 X- k: N) W' ^ set my-column -10 w- t& l! j! Z8 p
set my-phase -1
. J( t* y& O( {, f! g8 D- z set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets6 C4 N! H) `1 l
set roads patches with
Y' v4 ]9 ]$ v; \ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
6 E z+ y/ q. b3 _ (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
6 L& A q" x) w: ]6 L( f, a set intersections roads with* e- g; \4 F) r% E. Q8 ~/ S5 A* r
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
7 c6 v9 {7 d/ t! `% m (floor((pycor + max-pycor) mod grid-y-inc) = 0)]& K$ L* G' o- I
1 ]0 c* c" L+ H8 I7 c$ z- E7 s ask roads [ set pcolor white ]& K& a2 o8 B, a* @" @" 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?
; o5 k- S' ~& Y2 F( q5 p set roads patches with3 K8 a/ i9 U) e$ E
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or1 u$ i- m* \0 y% V, X. D
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
2 B4 z' S( M1 A9 h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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