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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。 U, j) B o7 m6 o, w: [
netlogo自带的social science--traffic grid这一例子当中, ~8 D$ V+ k% ?: N* s
globals+ C- p9 [: S8 F0 o1 J
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grid-x-inc ;; the amount of patches in between two roads in the x direction2 Z7 @; w: f( |- x" H: E6 R3 B2 w
grid-y-inc ;; the amount of patches in between two roads in the y direction
! W" _% J% K) V, v% G acceleration ;; the constant that controls how much a car speeds up or slows down by if: g. X1 v' f6 p p: c3 Z
;; it is to accelerate or decelerate
) B/ a0 j. J" M* S. f phase ;; keeps track of the phase4 o% N! F( a* @0 W# T
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure0 j% _0 n6 a H1 ~; N: q" ^
current-light ;; the currently selected light3 O* Q$ e" a/ E+ A
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;; patch agentsets
% k7 C: K7 s& v# k1 e intersections ;; agentset containing the patches that are intersections1 m+ _/ i' A( f5 P
roads ;; agentset containing the patches that are roads
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+ m) L3 Y( N& e) X m3 dturtles-own% U: _" Y/ \# z
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speed ;; the speed of the turtle
$ \" D8 q8 y, Z. @5 E+ E* e8 ^ up-car? ;; true if the turtle moves downwards and false if it moves to the right7 c2 }3 }) `0 V
wait-time ;; the amount of time since the last time a turtle has moved4 {/ j/ b. o' k1 g
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patches-own; H& w7 n. z m8 K& Z% U
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intersection? ;; true if the patch is at the intersection of two roads
1 p5 g( a0 h/ o, {& B" I green-light-up? ;; true if the green light is above the intersection. otherwise, false.
. H! C8 c! q+ W5 S# i$ o: r4 h ;; false for a non-intersection patches.( W/ [7 v) R5 j0 t4 h3 `( S
my-row ;; the row of the intersection counting from the upper left corner of the v8 c- v; Z" W' ?. k
;; world. -1 for non-intersection patches.
- q( L0 K$ `' W: `# T% v( {, L- L& D my-column ;; the column of the intersection counting from the upper left corner of the& O+ p! A$ C! O" Z) x* J
;; world. -1 for non-intersection patches.
- F$ K6 A: D, y' E6 ^( ? my-phase ;; the phase for the intersection. -1 for non-intersection patches.+ c: H% e8 K, q) A& h+ V
auto? ;; whether or not this intersection will switch automatically.
; f3 k# W- J9 w9 _( b9 u" X+ f( m1 N: l ;; false for non-intersection patches.
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$ Z& m7 T( T8 H4 C. C8 h7 ~' L;;;;;;;;;;;;;;;;;;;;;;. H, x" }5 a% X- }4 q
;; Setup Procedures ;;7 H |( B- S3 [0 C
;;;;;;;;;;;;;;;;;;;;;;
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4 Y% ?( d) r9 p' ]1 \, {* T I;; Initialize the display by giving the global and patch variables initial values.
( J4 J; V) }* {& \;; Create num-cars of turtles if there are enough road patches for one turtle to
, y3 y; Q2 Q) x, {! S;; be created per road patch. Set up the plots.! h8 \% D5 f3 M3 v3 \
to setup8 a5 g! n% ]' {$ F" z4 Z
ca
2 x5 ]3 _6 h$ C T setup-globals0 p& N- l0 P. X! K$ l
& R: W6 ?/ n; L- v: I( ` ;; First we ask the patches to draw themselves and set up a few variables# x$ [3 C4 D' M8 r ^$ T8 T0 Y
setup-patches
! v/ b- d$ @+ e' N0 _5 U& x4 w make-current one-of intersections. R5 z$ C- H# H. {; S
label-current
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- n! m. c) k" d. [4 K& f- x5 y set-default-shape turtles "car"" u2 I: o1 E; ?2 d9 T
& d4 o) c3 ?+ @5 O0 q* u if (num-cars > count roads)# Z9 J% f ?- p8 K
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user-message (word "There are too many cars for the amount of "
; q! D2 U2 y# V+ B "road. Either increase the amount of roads "
1 @# Z( |. H* ~4 b% j' V K "by increasing the GRID-SIZE-X or "$ ^' G9 [# C) O4 n
"GRID-SIZE-Y sliders, or decrease the "
/ n" E# b, i% |1 V "number of cars by lowering the NUMBER slider.\n"0 h. h9 h3 Y+ K9 s
"The setup has stopped.")
& V, g: f) V4 ]1 r' n- @$ { stop
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0 F( Y. y! |7 i% i ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color. t7 h# u }9 z) h2 I
crt num-cars; j6 G! P/ E! e
[
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set-car-color
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;; give the turtles an initial speed
' M' s, H9 a2 a0 o ask turtles [ set-car-speed ]* F) x7 Y4 O$ v& G& m' u7 q
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reset-ticks
2 y3 f4 v9 C( p7 M* D7 B' Nend
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;; Initialize the global variables to appropriate values! Q+ ?, i( u. ^) _* i- \ M, e
to setup-globals
3 r$ D0 o# X7 S k+ y set current-light nobody ;; just for now, since there are no lights yet
/ j3 p6 L, X2 i7 X set phase 0& j: u. t% W7 c' ^
set num-cars-stopped 0
# X* F; `$ r& d" P& ] set grid-x-inc world-width / grid-size-x2 n9 V' f4 Q- l
set grid-y-inc world-height / grid-size-y# | }9 h+ `2 }4 V: {: k% j
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
; A% s Z( }: L( `! A set acceleration 0.099
" E+ S Y& r {0 T! e0 oend
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" E& E u: S& A3 M;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
, @% p5 _1 {4 Q0 K7 T$ I/ u" U;; and initialize the traffic lights to one setting
1 R Q% z+ ~/ e& n1 m c8 ?to setup-patches
: q" i6 A! }% ?9 e5 X1 _5 G" ` ;; initialize the patch-owned variables and color the patches to a base-color
6 c! u/ s/ r, B+ x7 K$ s; N ask patches
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% e. j& W% l3 {0 `4 i5 J set intersection? false# u( s+ Y Y3 F
set auto? false/ D) k/ J3 F( s& T( j2 k
set green-light-up? true _- i# C4 J Q& |# \! ]+ W
set my-row -1" j6 G" _* [, I& |0 Q
set my-column -1
5 L% |6 n- f- `8 g1 D4 K set my-phase -1
9 u6 q, }* P1 V: o: [" R set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets3 @, ?" j% q; R& e
set roads patches with
1 h5 F; o: r! f/ E% p [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or. ^( k$ s( M, _5 l$ A' N
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]4 z" { Z4 P8 \. y% \" T
set intersections roads with" O, x( W! N+ X6 h6 p
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and6 \* w2 ]: z( K9 Y
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]2 g# V9 q9 s7 p) B: S4 X
setup-intersections7 p+ Z1 w0 i# v3 l2 w
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其中定义道路的句子,如下所示,是什么意思啊?
: W6 S. w" f- o. q! V set roads patches with
- p$ }0 P; \ U1 G; K( A( W [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or$ ?' ~2 l, V, C1 Z; ^
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
# U! M5 ]1 r2 @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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