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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。! W# M4 M( e% u
netlogo自带的social science--traffic grid这一例子当中,, `$ R! o( e0 ^5 Z
globals6 s: R/ x) a b; _% O
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grid-x-inc ;; the amount of patches in between two roads in the x direction( u& Z& N- c) Y' G+ B" V. S0 i
grid-y-inc ;; the amount of patches in between two roads in the y direction
, h" [9 H2 _9 \5 E! y' E acceleration ;; the constant that controls how much a car speeds up or slows down by if
4 s, C. v! @6 L% P" n7 ] ;; it is to accelerate or decelerate0 D8 j/ O' H& c6 v; \, a
phase ;; keeps track of the phase
1 B" R, X8 k, @4 o* @ num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
. y5 d. @) s0 W1 { current-light ;; the currently selected light
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;; patch agentsets
, m, w& E. M4 k6 V' S, \ intersections ;; agentset containing the patches that are intersections
/ k3 S3 ^3 x. u, S' q roads ;; agentset containing the patches that are roads4 R; T3 s7 g/ k4 R- e$ ?5 D
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3 N4 N+ ?; c" W+ jturtles-own
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- I3 P$ h* W _. ^" ]# L; F speed ;; the speed of the turtle
' K* R0 n6 c9 M6 [" e up-car? ;; true if the turtle moves downwards and false if it moves to the right
! j, I, T6 r) U/ X wait-time ;; the amount of time since the last time a turtle has moved# G0 e& @# u! q( a h$ X+ E
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads) a Y9 y; X3 Y8 k% ?( D/ C5 {
green-light-up? ;; true if the green light is above the intersection. otherwise, false.0 _% C7 {: c5 F2 j
;; false for a non-intersection patches.
) {1 V3 R/ p$ l9 Y2 @6 R my-row ;; the row of the intersection counting from the upper left corner of the
B4 t) H- u! d( X* w, ^* K7 d7 ~2 s ;; world. -1 for non-intersection patches.
/ {4 G! i6 `. V) ?3 D4 d5 @7 G my-column ;; the column of the intersection counting from the upper left corner of the) e/ w1 P# L: b0 c, t1 I: c
;; world. -1 for non-intersection patches.
* G9 T1 l. y) w( r2 }7 @% d4 _ my-phase ;; the phase for the intersection. -1 for non-intersection patches.& Q$ E( y1 Y' B
auto? ;; whether or not this intersection will switch automatically." Z" k4 B! e/ Q: Q0 W/ `
;; false for non-intersection patches.4 n" E6 c! y5 h( z' Y0 y6 G
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;;;;;;;;;;;;;;;;;;;;;;0 z! j% H9 ]+ L! [7 U4 c
;; Setup Procedures ;;
B: \5 {" k n! R( };;;;;;;;;;;;;;;;;;;;;;
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& H( I' G1 t( \3 L8 v;; Initialize the display by giving the global and patch variables initial values.) I8 b t/ T- [6 Y3 H: t
;; Create num-cars of turtles if there are enough road patches for one turtle to
& Z8 t! n7 M5 Q) N* r, G8 };; be created per road patch. Set up the plots.
- y, P; K4 ]. ]9 ?to setup
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setup-globals0 W- ~ J. x* l2 |5 P1 C
; q1 F: D( K0 ? ;; First we ask the patches to draw themselves and set up a few variables% J) {! j; V: v" A
setup-patches
/ R! s9 g9 M8 a, J# X make-current one-of intersections
/ l& }. D' Q8 ?% `' @ label-current
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) K* Z$ O+ f" O' v4 m3 _6 [9 Z set-default-shape turtles "car"
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if (num-cars > count roads)
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( O4 h+ ~% m, s0 V3 c- b, _0 C user-message (word "There are too many cars for the amount of "9 `& ?' o# w' ^( T2 N& K6 T7 F
"road. Either increase the amount of roads "
/ r( F/ a- o5 g7 X5 X" a# t7 s6 B "by increasing the GRID-SIZE-X or "9 M, S/ h2 ` j$ x6 o3 I9 T
"GRID-SIZE-Y sliders, or decrease the "2 ?9 b/ n: @ T' N& q. R
"number of cars by lowering the NUMBER slider.\n"
8 y' ~& z: A' v$ y, f, D "The setup has stopped.")+ O; J" k1 t6 Z
stop6 X: w- G) d4 d+ z! Z/ \+ _
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) A% U4 T% v& s {& ? ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
1 T8 a1 D5 v$ j/ d2 a crt num-cars U7 T5 _8 W. ^( _) `
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setup-cars: }5 `! `0 j/ G3 T
set-car-color
6 z. b; _' U, U& _# ^- n record-data
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. H/ u$ v5 I2 Y! I6 K# ^" i ;; give the turtles an initial speed* H% e" m6 H! a
ask turtles [ set-car-speed ]% j/ ]7 J$ \0 X
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reset-ticks1 [. P5 w; A6 ]+ K# E; x/ g, i; _
end- r( M/ m5 v% A$ i0 Y7 `0 \2 Y
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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 yet9 ^% R' ?8 z, ` c( N" g# z
set phase 09 q2 }% G4 E1 F* S- q& e) U3 e
set num-cars-stopped 02 {$ h, K( A" E5 c9 M
set grid-x-inc world-width / grid-size-x, J: T' I( V& h1 Q z( h3 q
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( c+ L/ n8 D; P( g% ]2 \& }; R7 S
set acceleration 0.099) o: G! g9 M* k
end
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4 o& P V' v5 t6 K r9 _' `# };; Make the patches have appropriate colors, set up the roads and intersections agentsets,/ [9 ~- Y+ b1 B i% j
;; and initialize the traffic lights to one setting, \( S% Z! f, T. v4 c
to setup-patches N! {' M& ^: {' \
;; initialize the patch-owned variables and color the patches to a base-color5 u& f" k S% I1 m" N0 s
ask patches
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! B4 o( ]7 d# _# a set intersection? false5 u z* \9 q' D+ B5 T
set auto? false2 O8 H, N# }3 K7 Q( ]0 |
set green-light-up? true& j% ?( w5 x0 o- s
set my-row -1
' N6 I& \% F! f. v2 _ _6 T6 R set my-column -1# G$ y# p$ v8 Z: ^ F1 J" B
set my-phase -1
8 ~3 ?* y p! x: d2 b: {/ }- o+ L) N! w set pcolor brown + 32 ^0 j) |4 X' J
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;; initialize the global variables that hold patch agentsets2 h9 n; c7 e$ x( k
set roads patches with
2 V" @: y6 z7 E9 p) @0 ^" S [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or+ e$ Y& g# o2 K" t0 w
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
) q$ a5 m6 f S- @( D6 } set intersections roads with
5 Y& E1 T" T" ^6 q% D6 `. q [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
5 Q) L( E( S! c3 U. w# y (floor((pycor + max-pycor) mod grid-y-inc) = 0)]7 N6 }5 w( a# P4 u/ s! W
" i" n8 O6 ?, a% j8 Z2 f ask roads [ set pcolor white ]
) |. b1 r; A0 m2 V+ [. K" i 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?# O ^. {- d5 n$ u7 W# l+ I" [ ^
set roads patches with( W* n2 e4 {1 Y3 ~6 V" o
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
9 [" \2 Z" v8 P+ z, H (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
/ l8 _$ f* t" `$ u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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