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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。
7 E) K% n' O( V ^' y; hnetlogo自带的social science--traffic grid这一例子当中,
~, M2 N- U3 a; u4 nglobals; x- ^6 S; M6 T* r
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grid-x-inc ;; the amount of patches in between two roads in the x direction
" A1 ~/ H! I0 H# B- p/ X# J grid-y-inc ;; the amount of patches in between two roads in the y direction& F: I7 {" y1 }6 a: W: X9 Q
acceleration ;; the constant that controls how much a car speeds up or slows down by if: _( m7 n. |8 q% K: ^5 h
;; it is to accelerate or decelerate
/ K* h1 }$ V5 B phase ;; keeps track of the phase" l B4 f! Y6 r/ g' v: r6 L
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
5 q& T3 r M" E( [: {: d q; Z current-light ;; the currently selected light# Y6 X, }$ L8 ^$ W) }
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;; patch agentsets' ?) ~9 ]$ J) @
intersections ;; agentset containing the patches that are intersections
. } M- i0 E7 Q roads ;; agentset containing the patches that are roads
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turtles-own# k+ f- v3 z& X, i% x; \
[
' B |5 a: a' `" q' h, ^9 ^ speed ;; the speed of the turtle R0 ?& Z& Z4 J0 n# A
up-car? ;; true if the turtle moves downwards and false if it moves to the right
, _: x9 D2 t8 V, h# h8 w- p 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
$ M' y& ~6 I3 | \ green-light-up? ;; true if the green light is above the intersection. otherwise, false.) v: a) t- U0 C+ U2 C6 \
;; false for a non-intersection patches.
" F+ |- u, j; I( X+ i my-row ;; the row of the intersection counting from the upper left corner of the" g3 ^& Y5 A1 |' Q; f* T
;; world. -1 for non-intersection patches.8 }* ^7 Z5 I4 u0 {. l1 w
my-column ;; the column of the intersection counting from the upper left corner of the7 g, S- { b) `+ K
;; world. -1 for non-intersection patches.3 C- z+ c9 ?6 t8 m* A b4 K
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
0 e/ a3 X) V. w8 Q( t# z auto? ;; whether or not this intersection will switch automatically.
. d, m4 O& w; \7 _3 p2 |1 G ;; false for non-intersection patches.) Y% ^- n/ U' |" ~# U3 {! a. t
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;;;;;;;;;;;;;;;;;;;;;;! _7 V) K! D( G' F$ ?
;; Setup Procedures ;;+ D% s; [/ T4 c, k+ h, H2 x0 P# R2 C
;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.2 E' ~7 f+ U$ G5 X# y" u% |: E
;; Create num-cars of turtles if there are enough road patches for one turtle to
4 g8 F/ @0 e1 z$ h# W;; be created per road patch. Set up the plots.
2 j7 u V9 i" C# wto setup* f; p5 ]; u& M. D% [7 W. K) D5 x5 q
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setup-globals, `# F1 I) N& n3 D4 }$ ]% S) n
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;; First we ask the patches to draw themselves and set up a few variables1 a. S4 }9 X; S3 T9 X' R
setup-patches
4 W3 n; z z4 u make-current one-of intersections
+ C0 t7 }. A/ C# ~7 G label-current5 a- S: L/ t( ?; h1 A1 g1 x
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set-default-shape turtles "car"4 a, x) X& r! t' S( a h* X
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if (num-cars > count roads)
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4 Y' J# \& W6 W4 V, G0 q- N( H user-message (word "There are too many cars for the amount of "
; Z8 a, A! p( J# ^ t "road. Either increase the amount of roads "
/ T# G& v( o6 {( l "by increasing the GRID-SIZE-X or "" o' G% {) v* Q. n
"GRID-SIZE-Y sliders, or decrease the "
7 G! p( ]9 i2 N' k "number of cars by lowering the NUMBER slider.\n"5 T9 H# B0 {9 Q8 ]* w$ |
"The setup has stopped.")
- e6 n8 i+ Y4 w. Q3 B( N- j9 R7 Q stop: c! U8 e4 T3 b B
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color6 m3 B4 s! ` w" W S
crt num-cars
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1 z9 X. p* x T. G4 O/ Q1 l% f setup-cars/ S3 R* t6 v6 \! j! f
set-car-color- o9 W- S% f: D& Q7 G, t
record-data
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9 ^2 s; v, J( q1 O0 k x1 T ;; give the turtles an initial speed6 n U: e! j8 Y' q# i
ask turtles [ set-car-speed ]
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* z$ l7 t# E. s! L" P( p6 b" j7 P reset-ticks/ K. y& l; X. U- K t
end7 F, q' C; c5 p7 W3 q. g! G3 k# R
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;; Initialize the global variables to appropriate values6 G' m' H- V" u
to setup-globals* a9 M) `: a7 d* T
set current-light nobody ;; just for now, since there are no lights yet# e' u; a* S" T
set phase 07 d0 {* [* p9 n
set num-cars-stopped 04 N; q( W. n3 K7 I# w1 x8 ?
set grid-x-inc world-width / grid-size-x5 s: X4 o" k5 O7 F+ H$ q0 Q: H
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
- m6 k, U# t6 k9 a set acceleration 0.0998 i' a0 u1 i) P% O& ]
end0 ^1 n$ K2 r$ e7 p6 l9 L
7 y# h) Q+ ]8 u K* T;; Make the patches have appropriate colors, set up the roads and intersections agentsets,- e3 ?8 V9 W, Z; a: l
;; and initialize the traffic lights to one setting6 H+ m9 ]0 A$ k* `
to setup-patches' n8 q0 W3 d# O% m
;; initialize the patch-owned variables and color the patches to a base-color
! C$ P, [# N4 A K ask patches. f/ d; Y9 ]7 Y x/ D
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set intersection? false, I$ `, M5 I a. u8 w
set auto? false* `* y3 d! w. s8 I, Y" |% S$ N& L
set green-light-up? true
$ `! r; p3 h" T& K* I set my-row -1* h& ]7 e5 x8 A! Q8 m
set my-column -1
$ Z" H. D7 t3 T- v8 P% i- ] set my-phase -1
! q0 e3 w8 Y' U. W2 N$ ~& |1 u& [ set pcolor brown + 3! o! q3 v& U5 ?. G
]
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2 u3 |8 W9 x4 C( y" @$ ? ;; initialize the global variables that hold patch agentsets
: H+ K6 u7 L. | set roads patches with" z4 l& e, a- h
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
: u2 ^ ~' H* N. y" F7 u (floor((pycor + max-pycor) mod grid-y-inc) = 0)]5 `% x$ a b8 v$ {* W" q
set intersections roads with4 L& _) N5 K/ ?% I7 J# k% ^
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and* F7 `% I; S' o* `
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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. }$ F% u O1 C2 Q ask roads [ set pcolor white ]( x# {9 L" U; h9 W4 O; `
setup-intersections+ ^. Z7 w; H3 Z
end
: ~) ]0 S% X/ i- E2 }) I% u3 C其中定义道路的句子,如下所示,是什么意思啊?' O2 d+ s% w% v2 d# ~2 R
set roads patches with
1 U8 g; v/ \4 O2 V) u* V. b9 p) T [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or, k* [! ^+ H9 o( Q0 p Q# ~" X
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]' I5 k/ o \1 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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