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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。9 H6 A! ~* t6 D( O4 b7 Z
netlogo自带的social science--traffic grid这一例子当中,& q: T- K. k+ Y9 {7 F2 F* f# @ b: k
globals' v: U0 h: ^* F8 }
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grid-x-inc ;; the amount of patches in between two roads in the x direction2 i. W1 Z( p: M/ A4 X2 Q' ^! g
grid-y-inc ;; the amount of patches in between two roads in the y direction
( [) M& b* C; | acceleration ;; the constant that controls how much a car speeds up or slows down by if
# }7 i- |/ a B7 M% } ;; it is to accelerate or decelerate
+ f; }9 P6 i6 W7 L phase ;; keeps track of the phase
* O8 Q, ~+ R. s: t num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
& b" q4 ^- N3 [( P) | current-light ;; the currently selected light5 O' N3 P$ a, \! a4 y
2 \! ]0 P8 U9 M2 w& B9 _7 K9 B- v ;; patch agentsets
) ^- \; x( i s4 E* y7 j intersections ;; agentset containing the patches that are intersections
8 v" D6 Y) g7 `6 A: i3 v. o roads ;; agentset containing the patches that are roads1 j, t6 H/ o2 K, H" t. i8 P- @' ]+ A
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. k1 ~! q* l* H1 E6 {/ B2 n' rturtles-own3 |3 e% X+ `) w
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speed ;; the speed of the turtle# ^& y+ V( R/ }* R) H2 J. b
up-car? ;; true if the turtle moves downwards and false if it moves to the right
1 V# |+ a, }" e# D7 I wait-time ;; the amount of time since the last time a turtle has moved' i" f+ N/ c2 |" L, v4 H r# M
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads3 B5 L' F5 H& b w4 D1 u4 B$ r7 ~$ k8 l
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
/ A1 g7 j$ w, @9 p" \; b |$ U) R ;; false for a non-intersection patches. u2 ]5 s; z2 `% w; I
my-row ;; the row of the intersection counting from the upper left corner of the- }& e2 h6 e/ L4 E
;; world. -1 for non-intersection patches.0 S- A+ w8 X+ p1 l# Q
my-column ;; the column of the intersection counting from the upper left corner of the
! u3 C4 c4 x5 _5 ^ ;; world. -1 for non-intersection patches.
3 z, l' c; h0 T+ ^4 @# M- s' B( Q my-phase ;; the phase for the intersection. -1 for non-intersection patches.
7 i$ I) {. e1 G" P5 c5 _ auto? ;; whether or not this intersection will switch automatically., S, ?6 r# P- l( L% |7 p
;; false for non-intersection patches.
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, _8 }0 }: L6 `0 y;;;;;;;;;;;;;;;;;;;;;;2 Z' ^, [/ R* q4 e$ \3 V' y1 t
;; Setup Procedures ;;
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' z$ W" ^+ T! T5 P/ R! l;; Initialize the display by giving the global and patch variables initial values.
- Y0 ]: C4 W6 b" d4 [2 g;; Create num-cars of turtles if there are enough road patches for one turtle to3 c3 D' }) k* D p' G. u
;; be created per road patch. Set up the plots.
; Q& H, R* S; z! G$ `% N# Fto setup/ n" A; {+ j, p: g" O
ca
6 ~; ~" I. E: Z3 u ~6 | setup-globals7 g2 m% @ t6 a! l2 s/ {
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;; First we ask the patches to draw themselves and set up a few variables
) t9 y4 u _( a3 t5 y3 G$ w% z setup-patches
7 e. S% p7 i5 Y+ N6 V make-current one-of intersections
0 W/ u) D2 q. _ Y* G4 d label-current6 ]# `: @/ D$ J, x" O" x% B
5 d* l0 x! h; G7 _' _ set-default-shape turtles "car"
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5 U ~, `& j0 M- t& D if (num-cars > count roads)- J- ?6 H" |0 U, `8 _6 i$ I I
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user-message (word "There are too many cars for the amount of "
, h* \+ ?5 U6 V "road. Either increase the amount of roads "
?8 Z- `" `: ]4 A4 a' y "by increasing the GRID-SIZE-X or "% E: ]7 u1 A. `1 F1 o
"GRID-SIZE-Y sliders, or decrease the "
% t( ?$ m! o7 G: z "number of cars by lowering the NUMBER slider.\n"
8 U# m! m4 P! M0 Y/ U! N5 I' k "The setup has stopped."). F) ^2 z% y8 `/ |5 v$ R+ B; t; O( O
stop
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0 q3 Y8 n2 P$ q3 f5 M3 G$ I% N ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
( U' v) s/ H; }# Z: q9 ]8 v crt num-cars( O. U! c/ L5 h: p+ n l
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4 T4 `# U. `3 B8 k) a$ c setup-cars
/ ?9 t& ]6 }2 d set-car-color
* {; Z) P7 U/ v& X record-data6 r3 j1 y( w. q
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;; give the turtles an initial speed
7 w5 J* S: U4 S! i/ _# i ask turtles [ set-car-speed ]
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! O+ U+ Q2 t. i5 M3 L9 L reset-ticks
1 v: w( D# V0 T+ n% H$ oend
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;; Initialize the global variables to appropriate values
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set current-light nobody ;; just for now, since there are no lights yet
' u2 R" p) X0 }5 `) p/ B set phase 0
& L1 v7 z1 V7 E# T- g" l; {. D set num-cars-stopped 0' x# ] w' V/ V- b5 W- Y
set grid-x-inc world-width / grid-size-x0 O. z1 z* e$ x
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
& P% D1 e& g, Q' d* y9 x8 ? set acceleration 0.0994 y5 l8 H% [! E8 Q/ P
end7 t( }: R: u) n: T5 c1 X, t$ k5 }+ Z
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
2 D$ s6 ]9 E0 [. e8 i, Y1 D;; and initialize the traffic lights to one setting X2 ], S! d. K0 x% ~) M
to setup-patches& A$ ^8 w$ E+ V- {6 N3 [5 ]2 T! C* F
;; initialize the patch-owned variables and color the patches to a base-color5 t6 u) d4 D: C3 t9 I
ask patches
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7 h9 `; w! m0 z {6 o& k set intersection? false* j9 ^+ w' N# i2 B, ~* o. [9 _8 A
set auto? false5 E+ {7 }% E8 d7 r( }
set green-light-up? true7 p1 r2 |5 g" l) a( F& T* D3 j
set my-row -1
) F! {& q& Z" \, ^/ \ set my-column -1 m/ ?% Y) L% c. K* m, f( K* R; J
set my-phase -1
1 f# @# h+ p e& k3 ] set pcolor brown + 3) ^: A8 d/ J. ?5 ~
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;; initialize the global variables that hold patch agentsets
9 i# s/ H0 f7 | set roads patches with
' T: t# R! p# i3 ~; E$ G2 H. O [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or) ^2 K/ U* y. m! j
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
2 x, m, N0 v; I* |+ b0 A* T set intersections roads with0 `1 j5 m9 D7 p) _$ `: D
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
# X$ A3 k+ [. Y7 @. W% [ (floor((pycor + max-pycor) mod grid-y-inc) = 0)]* M, a* h- z5 @7 H1 d# @3 K
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ask roads [ set pcolor white ]1 d0 l+ X! O2 I1 j8 ^5 t# v+ s( `
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?
2 u% G0 ^6 L/ D( } set roads patches with ^+ c- [$ K( @2 i i" R5 T( Z
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
8 w5 O/ s8 @" _' \ (floor((pycor + max-pycor) mod grid-y-inc) = 0)] L+ T4 }% q7 O$ |/ h* t
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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