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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。1 x, R @0 J- f8 i7 K3 s* N
netlogo自带的social science--traffic grid这一例子当中,
7 V" s1 G5 H6 P# Xglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction3 L0 m2 F5 h3 \/ H( |6 [. n
grid-y-inc ;; the amount of patches in between two roads in the y direction
% b. \2 p; c" y4 d$ o acceleration ;; the constant that controls how much a car speeds up or slows down by if
: b/ h3 m3 f' U6 X) V0 T+ B ;; it is to accelerate or decelerate" W8 v) A9 k1 b
phase ;; keeps track of the phase0 I7 S/ H2 F0 ^/ _ H
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
$ a1 ^7 A, p' w, _- [0 w8 ] current-light ;; the currently selected light: Z' T6 t2 z4 Y+ K' g. y
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;; patch agentsets
" R4 c x* a6 u; k* S- k intersections ;; agentset containing the patches that are intersections
1 u% a) _+ P6 L$ u& [& o roads ;; agentset containing the patches that are roads
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0 {$ @9 p5 G! L! R! eturtles-own
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speed ;; the speed of the turtle+ U6 g( D" i) _& u, a
up-car? ;; true if the turtle moves downwards and false if it moves to the right
. p0 l) C9 S( ~, R3 I& n wait-time ;; the amount of time since the last time a turtle has moved
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patches-own. I; d. ` _: ?4 M) [3 p
[
) ^: L G. _5 ~7 z1 n1 R intersection? ;; true if the patch is at the intersection of two roads8 K$ W1 [2 L% b6 v
green-light-up? ;; true if the green light is above the intersection. otherwise, false.2 }* z: H, S, M2 d0 n0 x, a
;; false for a non-intersection patches.
. m' r$ `0 V5 x% g! R0 i2 _ my-row ;; the row of the intersection counting from the upper left corner of the8 l( o5 Z; Q7 g9 u
;; world. -1 for non-intersection patches.* }, W& w% \( i
my-column ;; the column of the intersection counting from the upper left corner of the+ q7 i+ q* z7 }8 d& T
;; world. -1 for non-intersection patches.
$ V! _* g8 ~/ y# { my-phase ;; the phase for the intersection. -1 for non-intersection patches.
" B$ P0 L% d6 ?' j8 d* I auto? ;; whether or not this intersection will switch automatically.
7 E3 T. ]2 I$ B: t ;; false for non-intersection patches.
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6 P. N, d, u5 f3 n4 h: `( S;;;;;;;;;;;;;;;;;;;;;;
3 q! p; D) X* }$ {' ^;; Setup Procedures ;;
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9 s1 _, K# E' e( L& X! i3 j;; Initialize the display by giving the global and patch variables initial values.3 X, d& X) E( y' Q% J; z4 c
;; Create num-cars of turtles if there are enough road patches for one turtle to# i* v9 X0 e' r' ^. P6 b3 H
;; be created per road patch. Set up the plots.( ^3 V' G: e4 \
to setup
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setup-globals
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1 Y! @, F% I4 ~0 t) x/ h% C) ~4 I ;; First we ask the patches to draw themselves and set up a few variables
; l9 r0 J6 e5 P/ o setup-patches
7 ^: _3 O8 c8 F) D( K: Z# K make-current one-of intersections
, ~( I" Y6 y$ h4 {' u label-current
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6 D2 j. Y% U! |6 ^4 x, X8 _ set-default-shape turtles "car". U7 B# U6 y- m, K5 r: G' ~
8 x$ ]% S7 |8 x) _2 e" y+ f if (num-cars > count roads)2 o( G# ^) m' ]" E x) I
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user-message (word "There are too many cars for the amount of "
/ Z3 `, a; h3 l% ] "road. Either increase the amount of roads ") J+ U0 Q! s1 H' G( r, l4 t
"by increasing the GRID-SIZE-X or "
, v, @2 e4 T+ H: ^& A "GRID-SIZE-Y sliders, or decrease the "& d) e( X2 S2 u _" m& p. X
"number of cars by lowering the NUMBER slider.\n"
& X9 U5 p9 J: ?6 H7 y "The setup has stopped.")
0 o- b6 O* ^0 h) G stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color8 S7 ~+ [0 G n w% b1 R) v" k1 Q
crt num-cars
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1 G9 Y. e0 Z# w/ H3 \$ e6 J setup-cars" u* ^. O2 x! l f- M6 W: n! w
set-car-color
% H u% C; ^# O) W record-data" T7 }+ A) _5 o: x0 |3 y1 y' _
]
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;; give the turtles an initial speed
0 c; @" q6 k+ z( W/ g |7 \ ask turtles [ set-car-speed ]
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s$ _) d% \1 H reset-ticks7 X, e0 W. i7 r; ?7 w" Z) d/ r- K
end
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;; Initialize the global variables to appropriate values$ N" {! @) c! G$ j/ b4 N4 x: J
to setup-globals# L# n/ | G; d, ~# V/ x3 A
set current-light nobody ;; just for now, since there are no lights yet
b# H# A9 @$ W: m c- y. ?# M set phase 0, D* a: @9 Q7 N2 K3 z% o/ J1 H8 N: e
set num-cars-stopped 09 C" S& J6 L8 x' O
set grid-x-inc world-width / grid-size-x
% R8 @3 A8 i. o set grid-y-inc world-height / grid-size-y5 M/ U- X/ Q: ]7 `" M3 U( S: O% l0 i. [
2 k6 I( K, K& b" y8 Z6 ]6 s3 t# T ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary+ Q' Z8 n; V& R' J' `# y5 z4 m
set acceleration 0.099: g) h9 M9 U* f' I- y
end
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3 w; y4 n+ }" C;; Make the patches have appropriate colors, set up the roads and intersections agentsets,& i r! z. q& c) W9 }
;; and initialize the traffic lights to one setting+ k; [$ w R# W( y# d( ]
to setup-patches0 D1 e! \* o8 x9 l3 T! {7 T
;; initialize the patch-owned variables and color the patches to a base-color
% n+ i2 i4 y' X ask patches3 S$ D' y( J# S& c+ Z
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* q# L2 E, R! ^2 L, n0 [. J set intersection? false
`# B, ?4 ?* |9 d8 B* P9 \8 S set auto? false8 \% v9 g5 h$ A
set green-light-up? true1 n m+ `0 K: a1 E; T' X
set my-row -13 S9 I* e1 K* z1 Q* Y! c
set my-column -1
7 n7 }/ b# e$ N( R set my-phase -12 a( k# k' x5 ~
set pcolor brown + 3& g) K' B2 { _1 r) N) F
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: a7 u# L, R- V+ f: G ;; initialize the global variables that hold patch agentsets# d$ b; t$ j4 h5 k7 n. r
set roads patches with
: M. Z4 Z8 }6 K8 u& Z I [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or% I! w1 L3 M8 J4 q
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
! |0 B& h* k1 B' A4 K3 U set intersections roads with
6 U+ @4 T. h; B. z [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
q) L6 S- Z9 T0 W (floor((pycor + max-pycor) mod grid-y-inc) = 0)]7 Y1 k# U1 r4 k" G) R$ C# O
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ask roads [ set pcolor white ]
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其中定义道路的句子,如下所示,是什么意思啊?( o8 @1 m& {7 L* R9 Y
set roads patches with* a! X4 U8 Y4 @0 z1 p2 u
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or1 S( A; V5 m2 Y" W. w( T& S
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 V3 g( r0 h3 g. o' b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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