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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。
E5 D" n+ X9 h; _netlogo自带的social science--traffic grid这一例子当中," e% C; I) Q3 ?2 V+ P" T- S
globals
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! p; o/ j2 {+ }9 \) Y1 x+ y @ grid-x-inc ;; the amount of patches in between two roads in the x direction; {' J" b. ^. k
grid-y-inc ;; the amount of patches in between two roads in the y direction
) }1 b# k: g0 h! p: I5 [) y4 q acceleration ;; the constant that controls how much a car speeds up or slows down by if; H; C. o1 f* u- V
;; it is to accelerate or decelerate
1 m" i7 I) G1 u. h phase ;; keeps track of the phase
: o: C/ t; j( W" A num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
/ o8 B; } G0 y$ P current-light ;; the currently selected light9 V/ Q: F; h; {1 D k ?
* `; e0 w- [3 _ ;; patch agentsets
6 o" ^+ O |5 y" W- `; O intersections ;; agentset containing the patches that are intersections# H9 D1 X$ X3 S/ f5 t. H1 o
roads ;; agentset containing the patches that are roads
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turtles-own* Q% I, @- Q" X2 m; c+ n/ g$ {
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speed ;; the speed of the turtle
# d5 r6 g# v+ |2 H% ]! N up-car? ;; true if the turtle moves downwards and false if it moves to the right( O) w0 c$ T0 ?/ \3 |" ~! b
wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads" v @$ f+ a! H4 T* k
green-light-up? ;; true if the green light is above the intersection. otherwise, false.2 @3 X& @% B, P- d, W c: E
;; false for a non-intersection patches.
E# B& w4 e+ K2 Y, ?+ ` my-row ;; the row of the intersection counting from the upper left corner of the# e$ O. H' i7 w# b
;; world. -1 for non-intersection patches.
/ W1 E. s9 q8 ~; `/ W, J my-column ;; the column of the intersection counting from the upper left corner of the( W8 K4 o5 r3 ~+ z1 Z: O
;; world. -1 for non-intersection patches.+ z _2 Q9 Y3 u- m1 k5 L+ J ~- b
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
- q1 D/ ?$ @0 Y5 {9 M# l8 r1 U4 Y auto? ;; whether or not this intersection will switch automatically.
# B+ F Y% S0 B, L. f5 \" t( I ;; false for non-intersection patches.+ _% n) S* _, a( K
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;;;;;;;;;;;;;;;;;;;;;;4 `, a0 [" B" ]: Q3 u; ^
;; Setup Procedures ;;9 F: U( T6 C/ ?
;;;;;;;;;;;;;;;;;;;;;;
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; n9 \: }; T9 q" X2 D& N( N;; Initialize the display by giving the global and patch variables initial values./ n0 _- d8 C% {2 d' s
;; Create num-cars of turtles if there are enough road patches for one turtle to
( W E$ K x, m9 L3 \; m;; be created per road patch. Set up the plots.( V3 x7 a2 r H1 ~( @
to setup C+ c- l" L( W1 O3 j4 A8 @( p8 {; B
ca
[, I6 p5 h7 P( D8 [ setup-globals
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7 \) p9 j; b, M# K3 X ;; First we ask the patches to draw themselves and set up a few variables; [: `* c5 u. J2 f T0 d1 v8 p
setup-patches$ }) ]! [/ A$ N/ s; b) X. \2 U
make-current one-of intersections$ x/ d; E& p$ ?/ A# X3 L
label-current. ^& u, o. O6 f# c. k3 h3 N
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set-default-shape turtles "car"8 ]9 L. @! v, U) ~8 L7 \
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if (num-cars > count roads)& F$ [& R/ g4 |1 E+ u
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user-message (word "There are too many cars for the amount of "
' X7 a# I& ^' e "road. Either increase the amount of roads "
9 @0 B% r9 q, M6 M7 o "by increasing the GRID-SIZE-X or "
' ?" D# n/ s! N: k. s+ Q2 {1 ] "GRID-SIZE-Y sliders, or decrease the "0 ?* o6 H/ R# H
"number of cars by lowering the NUMBER slider.\n"
1 p# H2 ^" a5 C9 w: p "The setup has stopped.")& f( c! P; e, Y; N
stop
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" h% G' L0 u) y: Z4 ^+ D ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
& t6 w4 d: \6 u. ^( H% | crt num-cars
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setup-cars
/ Y1 M" j5 N, T; f& ^6 l# w" \& l* _; u set-car-color4 A1 `! x( P4 N
record-data: h$ @0 O7 w. E. r4 T9 e) q; w
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1 O* |/ F, l" _% \- F ;; give the turtles an initial speed
# F. B/ [2 z$ m9 i* x ask turtles [ set-car-speed ]
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& R* l8 K$ U; v W/ h reset-ticks
4 D% G( u- L% A* }end
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;; Initialize the global variables to appropriate values; t' Q$ h- U1 p# ~7 d4 G
to setup-globals
; l! ]6 E6 E) R: n set current-light nobody ;; just for now, since there are no lights yet
% f% [* T$ e4 Y( n& P4 W set phase 0: B" ?% }+ u/ p+ D
set num-cars-stopped 0
# c7 b4 J2 v- R8 E' G set grid-x-inc world-width / grid-size-x
' j9 Y9 ?* W7 I! _8 x; R* [* W: q set grid-y-inc world-height / grid-size-y* I2 t* _! K y7 b4 V8 b( L
, L( L4 ^6 h, Q/ Q' Y ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary; K- ^/ H7 k* |) j, B" w
set acceleration 0.099
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6 n% |# U- M9 e2 F ]# J$ I;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
" D" ^3 H7 e2 B, @- P. C8 X;; and initialize the traffic lights to one setting9 K- X" D& T* u4 ~: C
to setup-patches0 A- f+ W1 c0 ^5 [7 M' V
;; initialize the patch-owned variables and color the patches to a base-color
) i7 o. d2 F. ]/ Q+ ?( W1 f ask patches
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set intersection? false
4 C( d2 r; g" \6 _ set auto? false
8 A, L! q1 }& H; R4 e set green-light-up? true( K0 t7 U; o) Q" l/ z" Z
set my-row -1
2 q- W8 i. f5 d- H set my-column -1
8 n1 x8 o: [' d5 d; w$ c set my-phase -1- \( e j& {) H* c% P2 p6 ] S+ T7 o
set pcolor brown + 3
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1 ]% S5 V" } w( l4 ?; _ ;; initialize the global variables that hold patch agentsets" O0 j6 I; B3 x9 c4 G
set roads patches with
' o% E! B9 o6 G [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
1 J% N* C" T1 }* ?- @ (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
' R5 K% Z+ \8 t% F( \) Y5 t set intersections roads with
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(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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& o# d5 Q4 x* L ask roads [ set pcolor white ]2 n1 `4 w# C2 R P2 d) 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?
) Q% e: C8 i( I8 [0 b( u; d set roads patches with
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(floor((pycor + max-pycor) mod grid-y-inc) = 0)]7 Q* `) G: o' d" G' Q
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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