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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。$ Q# x" B/ M0 D* G- V
netlogo自带的social science--traffic grid这一例子当中,
6 U6 |3 V% o& p; Kglobals5 t( r, T( ?* n& Y' ^
[
! r$ b6 }0 n* ` grid-x-inc ;; the amount of patches in between two roads in the x direction
' y. v9 O' T) ^+ K: `$ ] grid-y-inc ;; the amount of patches in between two roads in the y direction: X2 N/ ?+ p" L0 T q& k
acceleration ;; the constant that controls how much a car speeds up or slows down by if- K4 M/ V" _( ~$ p$ s, B
;; it is to accelerate or decelerate# ~7 [ Q& _8 P
phase ;; keeps track of the phase8 W5 {4 h# ^' j: l% w X* E
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure H+ E) I& ]; c
current-light ;; the currently selected light4 d6 ]9 N( R& A0 G7 R
6 v) I3 E9 e- v+ c& `( N ;; patch agentsets
: y( d* X* r0 _7 ~ intersections ;; agentset containing the patches that are intersections
( n) _3 }4 z+ w! \% e" w roads ;; agentset containing the patches that are roads [1 ~+ B8 v* y! T
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turtles-own8 b8 o& I4 x0 C5 |) o/ z) c! S" X6 I
[
) B9 |# m c6 D$ B( r speed ;; the speed of the turtle- j) {, L' W5 G" W$ E
up-car? ;; true if the turtle moves downwards and false if it moves to the right* i U! I& Y. l' V$ B
wait-time ;; the amount of time since the last time a turtle has moved8 u6 S+ o" x% V) Z
]
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patches-own" N5 V& l0 b8 h$ Y3 |2 P1 Z b# ^, q- I6 X
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intersection? ;; true if the patch is at the intersection of two roads
% N+ u" p/ n1 \6 p- } green-light-up? ;; true if the green light is above the intersection. otherwise, false.
4 L9 `8 k6 M, y& m; o0 J! w ;; false for a non-intersection patches.
" [# N; S& W$ S7 d ?& v3 M* V5 G my-row ;; the row of the intersection counting from the upper left corner of the% U9 R/ p* }+ R; }+ o1 o
;; world. -1 for non-intersection patches. L! }4 G" y& [, a& z
my-column ;; the column of the intersection counting from the upper left corner of the
! l- ` n9 t i& [: U ;; world. -1 for non-intersection patches.
2 V5 q! ]) I3 P my-phase ;; the phase for the intersection. -1 for non-intersection patches.! F. O$ i( ], G6 O
auto? ;; whether or not this intersection will switch automatically.2 a/ t/ M+ R% ^! i
;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;6 u0 i. U# F D8 @2 }/ [
;; Setup Procedures ;;
( x+ @" b! _+ I" a! Z5 ^;;;;;;;;;;;;;;;;;;;;;;' `4 A; c1 m) y3 U8 h6 j* B
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;; Initialize the display by giving the global and patch variables initial values.1 A+ r6 k- }6 h: z* g% B8 J
;; Create num-cars of turtles if there are enough road patches for one turtle to5 g+ }0 ]0 a* b' l4 D" }6 a% i
;; be created per road patch. Set up the plots.2 {2 J5 k% _* D1 D7 `
to setup4 l( g+ b# g' V! p
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setup-globals! u* ~5 ]6 z( H5 `
8 k; X. }* [* R# q9 ~2 O+ {! a! Z ;; First we ask the patches to draw themselves and set up a few variables
1 J! |# U" A. N; M | setup-patches
: P( `/ y! @+ h8 c. X# J# p1 h' K% m make-current one-of intersections3 O$ m0 S+ V" P8 |, L) c: \, y, r- @
label-current/ v n9 Y: h$ Z: h
. e, q/ N a- W+ I6 L set-default-shape turtles "car"7 O ~/ o) b5 U' q. S! h! ^4 ^
4 X1 Y* H4 x: e if (num-cars > count roads)
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0 I2 V r/ @/ q; v, F+ s user-message (word "There are too many cars for the amount of " L, s ]: g* J6 `
"road. Either increase the amount of roads " f- E3 g& V, t1 w2 C1 h- b7 ~. p9 i
"by increasing the GRID-SIZE-X or ". y. {) K' i w" t% f
"GRID-SIZE-Y sliders, or decrease the "0 D2 M3 l! q) k3 ~3 ]2 Z5 |
"number of cars by lowering the NUMBER slider.\n". X4 `: u' ~$ j/ V* g6 k
"The setup has stopped.")
1 o* J0 N# i% t stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color2 p! L: a& C# Q3 Q( [" o. T) }* ^
crt num-cars
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( ^- H* y4 e- O5 X4 H6 \ setup-cars
8 O' y" T+ d i, w& n( j/ g9 ] set-car-color
. B* O" x, k8 ?4 k5 }8 R# } record-data
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8 r5 h/ h8 }/ E3 j1 w% T0 i ;; give the turtles an initial speed
1 K' l n. e% Q K/ c ask turtles [ set-car-speed ]# H6 s I# Q, Z( ]
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reset-ticks
, |0 `$ u3 h: X* _& N) g& `3 W* kend
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;; Initialize the global variables to appropriate values/ ~8 y8 X8 d$ Y. D0 a1 C& Q
to setup-globals
, I* I+ N$ d- z3 Y set current-light nobody ;; just for now, since there are no lights yet
' L0 h, ~) I0 J set phase 08 \ _8 A. R0 Z1 `
set num-cars-stopped 0# x, ?, P ~9 T1 h' O. r- {7 V
set grid-x-inc world-width / grid-size-x9 F/ C' K+ Q9 D$ ~4 F
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
6 i4 y9 `! S& |. s' n8 n0 y$ e set acceleration 0.099
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
5 G% n( I1 Q1 n& J3 a1 R;; and initialize the traffic lights to one setting' r" b) X. b0 K1 ? u+ |/ |
to setup-patches
4 _3 l, R1 G8 A7 J* G& C# ] ;; initialize the patch-owned variables and color the patches to a base-color
, w; h$ T% ]" h8 C {: U ask patches
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4 H: x" {0 R* z set intersection? false `8 `5 z" M) T
set auto? false2 f9 F. J" \5 R8 U, H9 y* Z" b% d
set green-light-up? true; u9 s R& f+ l8 }. o3 l
set my-row -1* F1 _- s; |) K0 y
set my-column -1. N% }) @. t" |2 T5 R
set my-phase -1. P0 o) F" O& U" i! D3 D
set pcolor brown + 3
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4 |! S* ~8 F; ]1 }8 Z; O ;; initialize the global variables that hold patch agentsets; ?2 [0 t, \- S. d
set roads patches with
% X" n' C0 T5 q! [; P$ C# f# B$ H [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
. `5 |0 G, ]& z& q* E9 |$ P2 W (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 ], h% W! @6 k8 [+ I1 O set intersections roads with
0 q- r& X2 J! Z* d7 B1 H [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
; O1 }; v5 o. N& I (floor((pycor + max-pycor) mod grid-y-inc) = 0)]- L" Y- z8 c6 C1 a0 w3 D
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ask roads [ set pcolor white ]
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其中定义道路的句子,如下所示,是什么意思啊?5 n5 b/ S9 d" O( @ ] W
set roads patches with5 g: b; ~+ A6 Z
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or/ @- ^1 f% i w1 W/ X. ^* q
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
' u1 A- A, O; }: f9 }* A% c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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