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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。+ D0 |. ~: \. I \7 m
netlogo自带的social science--traffic grid这一例子当中,
; |% i0 ]# F9 \globals
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# @5 {! U" f. t/ ?% N# P grid-x-inc ;; the amount of patches in between two roads in the x direction
7 f/ y5 i8 a& z4 D7 C grid-y-inc ;; the amount of patches in between two roads in the y direction
' W# V" U9 Q$ K acceleration ;; the constant that controls how much a car speeds up or slows down by if) s/ D* h3 W c: g
;; it is to accelerate or decelerate
/ j: z' c3 ]- i x! X! n) o) L phase ;; keeps track of the phase
5 A7 R- v4 e- Y# u num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure8 l# H' M$ q. N/ u# z
current-light ;; the currently selected light& a) ^7 t2 Y# ~. _2 P
# ]; S0 M9 N, o1 U, @: B$ k# G ;; patch agentsets
( [- v, t+ c1 a% n( s# } intersections ;; agentset containing the patches that are intersections) i' L7 p! h: u3 t
roads ;; agentset containing the patches that are roads6 Z* Q2 c9 q: n v
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turtles-own) x# H0 M* f2 [' @
[
5 l6 Z+ Y) Y- {- | speed ;; the speed of the turtle
- W$ R) H9 r( M z up-car? ;; true if the turtle moves downwards and false if it moves to the right
& y7 B3 U3 O: N1 D1 R& k5 z wait-time ;; the amount of time since the last time a turtle has moved$ k/ c7 J4 @- E( a4 P+ e! Z
]
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+ @4 w3 T$ e9 J1 i3 D; Npatches-own
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intersection? ;; true if the patch is at the intersection of two roads
6 C/ S4 t2 D, w0 s green-light-up? ;; true if the green light is above the intersection. otherwise, false.
8 S5 J, p# X% ^% t ;; false for a non-intersection patches.; K$ Y/ V0 D( q' m' ^
my-row ;; the row of the intersection counting from the upper left corner of the) k2 o! B- U: H/ ^& ^1 ?& v
;; world. -1 for non-intersection patches.
5 P" A4 m: ]; Z4 E8 V7 } my-column ;; the column of the intersection counting from the upper left corner of the7 w" e+ R2 r5 e k" Z$ ~
;; world. -1 for non-intersection patches./ i e# y. B( W: ]: {
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
1 \: x1 w. H3 }. c# D% I8 C( @ auto? ;; whether or not this intersection will switch automatically.$ A4 L }: S% }7 N
;; false for non-intersection patches.
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: \- p# Y3 R, k; m;;;;;;;;;;;;;;;;;;;;;;
. a7 k% u& ^: w" a;; Setup Procedures ;;! e5 _1 O9 G w; t3 D
;;;;;;;;;;;;;;;;;;;;;;4 C; }! s4 ]# W+ A! L
+ {/ Z& E9 o/ Y/ N) Y;; Initialize the display by giving the global and patch variables initial values.
7 e5 x( ]& q+ r& N% y+ _& x;; Create num-cars of turtles if there are enough road patches for one turtle to; o) F+ S( |# |$ a' }
;; be created per road patch. Set up the plots.
% O* n0 R* j1 q0 J2 ?' r* rto setup4 X8 H0 p8 ~- x/ [
ca# F- O$ p/ @0 n+ I& S0 x
setup-globals: Y# B; \; v* k5 r" l2 D6 f! J. J
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;; First we ask the patches to draw themselves and set up a few variables
( n3 `( d6 v" l8 V) D2 X setup-patches
/ v3 g5 U% o" z1 o1 J7 c7 C make-current one-of intersections
4 T8 ^* b. p, w label-current
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) N5 |) Z& k! q6 j4 |. j0 ^# \ set-default-shape turtles "car"
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if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "2 F' f. V. q& j h7 Z6 {4 ^- K
"road. Either increase the amount of roads "
, `$ D0 ]- \) @6 c6 m1 i& E "by increasing the GRID-SIZE-X or "3 e. S" g" j% Y* `) y/ w7 m
"GRID-SIZE-Y sliders, or decrease the ": p5 \" f' ^8 f; V. M
"number of cars by lowering the NUMBER slider.\n"
9 }2 l% b9 L% r+ \ "The setup has stopped."): j: t* a$ c( {2 U6 G7 H& {
stop" l6 ]& W: ?) G6 S: u
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' e2 U2 A- O; X3 d1 X- |! V6 P R ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color) Z v& K) C$ e' |7 v
crt num-cars4 J) ?/ E# P i) {* s5 T
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setup-cars. e0 f1 q5 x8 G! d+ \) c
set-car-color
& H8 y7 S/ E) t) y N* E) [ record-data R/ w8 L1 E$ X; N+ M
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- Q2 n( e6 e4 s K& Q( v ;; give the turtles an initial speed- g% F. x8 n) S4 ~" {- P3 p
ask turtles [ set-car-speed ]5 w: a, }* V; V' N- j( Y
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reset-ticks, [# a3 q, d( s! A
end
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* R6 Z) d( }1 M0 F+ F" O0 j4 d;; Initialize the global variables to appropriate values
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set current-light nobody ;; just for now, since there are no lights yet
" V$ A8 S' K" j1 ~- \, ? set phase 0
) o$ q v" h b, D set num-cars-stopped 05 {. ?5 }3 P3 L! S8 Z9 D$ Q( X
set grid-x-inc world-width / grid-size-x
6 E1 Q; l+ T0 u c+ K7 ~ set grid-y-inc world-height / grid-size-y
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0 x i& J/ ^# v3 d8 s' ? ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
, {& g# m; \& X! a: _, N) k' w9 e set acceleration 0.0993 l" h* q4 S7 A1 `9 _$ S
end; {% V; l$ W3 c) j
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
; ?; i/ b* z" ^7 n! c;; and initialize the traffic lights to one setting# {) {1 X; Z$ `
to setup-patches I/ B3 X, ~# |
;; initialize the patch-owned variables and color the patches to a base-color* p% ?: Q$ h' _# W' A, h
ask patches5 H: T* _* Q& J+ P( d
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set intersection? false
: Z" m. ?* `/ z set auto? false; y- C$ E% X; K9 Z: Y3 k% B2 ^
set green-light-up? true: p4 w, D/ C/ Q; [6 e( N
set my-row -1
e2 @* g1 G# D5 r3 l7 \" I/ v set my-column -1) \# K* }& [4 q
set my-phase -1
4 H* \" U- c: ?3 A set pcolor brown + 3$ J& i6 z* f9 W$ X' l
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: [3 ?* V$ n; R ;; initialize the global variables that hold patch agentsets
4 P( |' }5 ]1 D& f, ] set roads patches with
; e) F0 C/ L# ]; T" W/ |7 m [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
2 e/ @8 g# C- n& I (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
4 I9 q4 s9 B) G, \" y% ~% L8 ~ set intersections roads with7 }4 o; L0 y+ r* D! a7 {. [
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
# z6 Q4 t3 x2 o; ^: r% @ (floor((pycor + max-pycor) mod grid-y-inc) = 0)]2 Z e% [2 \- D
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ask roads [ set pcolor white ]0 k9 Q5 e3 O6 \' A6 j m4 k; |
setup-intersections) @) I# T& J2 A L
end. L$ f( b) @2 |" N
其中定义道路的句子,如下所示,是什么意思啊?
& r5 C' s, [) |3 X) b( x: S! } set roads patches with; A& I N; X) D/ a7 ~$ q9 M3 c
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or' x0 S, F5 i6 \7 w# q- d4 v
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
2 S" |' g0 e- ^6 F* j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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