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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- g$ S' l( Y( X- u
netlogo自带的social science--traffic grid这一例子当中,
: I) L8 z8 c6 Dglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction
1 X+ U9 C$ h4 I5 [1 h, n0 F grid-y-inc ;; the amount of patches in between two roads in the y direction
: r% n( r2 c; `8 Z: Q acceleration ;; the constant that controls how much a car speeds up or slows down by if% H; ?# A; e# x3 I" a2 j# r( Z% _
;; it is to accelerate or decelerate
* t5 d4 M$ `- q- ~ phase ;; keeps track of the phase
" L3 ]% T- i! u/ p0 ]; j- z2 Z num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
2 S4 g9 [% b; F+ G) j current-light ;; the currently selected light7 N; N0 U/ ^0 c( i
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;; patch agentsets
: z3 Z8 K, B9 f intersections ;; agentset containing the patches that are intersections
; Y9 k! z& T" t2 r! g* N/ c* k roads ;; agentset containing the patches that are roads. Z6 W& ~* C: b" Y" z) O8 y
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9 M! _. x9 A8 t1 V) d' w6 g. lturtles-own
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speed ;; the speed of the turtle- l e" [# f6 B8 ]% s; @
up-car? ;; true if the turtle moves downwards and false if it moves to the right! Q& H2 T/ T9 `# Z* H
wait-time ;; the amount of time since the last time a turtle has moved' W+ `8 r/ E/ x, h
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patches-own; l5 r- R4 H, R, P* d+ i
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. a3 c2 d1 H) L2 _& C+ X# C intersection? ;; true if the patch is at the intersection of two roads
( y* y6 \- V8 Y* P; b green-light-up? ;; true if the green light is above the intersection. otherwise, false.
2 T* i1 N5 K" ] P ;; false for a non-intersection patches.6 U6 j$ O* |. d6 n# q
my-row ;; the row of the intersection counting from the upper left corner of the4 A4 `, g; d* U
;; world. -1 for non-intersection patches.2 k; E' [8 G# ?! S. W1 P
my-column ;; the column of the intersection counting from the upper left corner of the1 ]" r3 P- f: _3 `! |% i
;; world. -1 for non-intersection patches.8 T2 e, F- I; O: X* |
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
+ }& Z# }2 I% k+ T) z auto? ;; whether or not this intersection will switch automatically.
: t# Y4 v! g0 C+ W ;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;
5 m( |5 l6 ~$ `5 T: J;; Setup Procedures ;;
5 N* j- Z8 x0 M j6 a- c7 |3 I$ T;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.
' a$ C" `: t! S* z* V0 d) X3 F;; Create num-cars of turtles if there are enough road patches for one turtle to
2 q( \ E- f! |- G- B/ [+ z;; be created per road patch. Set up the plots.3 V3 f2 K7 n% e1 A
to setup
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; h A! U& A R5 V9 Z$ X setup-globals! n& J; C# j+ q
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;; First we ask the patches to draw themselves and set up a few variables
$ M4 t* Y+ r( r# s% h) q+ y setup-patches, g( {3 }+ f+ p! D6 k$ }7 b
make-current one-of intersections
- d1 G+ _* @" g label-current7 |4 w( l" a+ r9 r3 Y/ ]- Y* s0 ^0 C7 a
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set-default-shape turtles "car"! S( u) v3 R: S/ m0 N
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if (num-cars > count roads)0 e6 } D% V; E. { H* I
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user-message (word "There are too many cars for the amount of "
% V6 z: h) l: } "road. Either increase the amount of roads "2 K: L2 X5 Y F8 f7 ^' s
"by increasing the GRID-SIZE-X or "! K' i2 X9 b. A6 b9 _- b% `5 ]
"GRID-SIZE-Y sliders, or decrease the "
! u$ @: H7 b" D "number of cars by lowering the NUMBER slider.\n"
" \/ b% O2 `& j2 I- R3 Z# y "The setup has stopped.")
: @8 @: M8 d% }( \/ I1 S% S% _ stop
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4 t# O+ d, w0 k) ~5 ?0 r ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
4 a8 e. a# G- m. r: W crt num-cars
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- @" z6 a+ y, S5 F$ [) R setup-cars! n1 P2 S5 S# n! q: n/ @) T
set-car-color, f8 R4 u% o. v$ c: C* w
record-data, a3 x: g7 w! q1 F; j
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; f' O O5 Q, M' \5 W# P; b! G ;; give the turtles an initial speed
+ Z+ f( k! N5 H% m s9 b! I& |4 ~ ask turtles [ set-car-speed ]# X1 r u& h8 F
8 Z7 a, @7 ?4 p$ c- u% X. j; o! v% h6 [7 | reset-ticks& v- Q& m/ q& p# ?1 ^' i4 B
end3 N& t5 S9 S% g$ G# F- u
# _" L# j R) {3 F4 t1 Y; w6 K;; Initialize the global variables to appropriate values
; `9 G) @' a- m# mto setup-globals
1 r" K& u; o) {: I" _. z2 O0 S. X set current-light nobody ;; just for now, since there are no lights yet
8 S5 q- f/ N. A I* h/ ~ set phase 0
5 a, Z+ B+ G" P! \7 n set num-cars-stopped 0% x/ ~$ g2 J4 H0 l @, G7 K( Y$ v
set grid-x-inc world-width / grid-size-x
F4 w3 A9 V8 o/ p set grid-y-inc world-height / grid-size-y- |$ H, z5 }4 d' |% u
k, ]- X" F* U2 ]) D. I) ?% a4 m; u ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary! T2 o% F! P! v4 X6 m
set acceleration 0.099; s! A L4 g6 o
end
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7 C: @0 u1 o+ G7 I;; Make the patches have appropriate colors, set up the roads and intersections agentsets,# d1 U/ H! R4 @( B! a
;; and initialize the traffic lights to one setting
/ ^- `) C. M4 D5 Z2 M ?2 Fto setup-patches
5 ^1 O+ t2 N1 ?1 B: w ;; initialize the patch-owned variables and color the patches to a base-color s" s6 l0 a2 _
ask patches" b5 |% g. x& n# f+ l, x1 b) E0 `
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/ n4 z: _" u6 s# ?- Y- d set intersection? false2 t/ [9 u# Z! f/ T/ b
set auto? false
# O! _+ ~2 }, a$ v+ S$ R set green-light-up? true9 m z( z7 N$ d: {, p$ H( N* g
set my-row -19 m/ g7 I' D, Z/ F! D& t
set my-column -1; D: U5 I6 @8 ~ @# c5 F7 g
set my-phase -1" O! V) L: b. Y4 {3 q9 h8 e
set pcolor brown + 3, t3 h" }/ s) l2 X
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% g1 Q0 s' r# t: T$ }' R ;; initialize the global variables that hold patch agentsets5 H$ f1 n; s* p
set roads patches with! I! |) g$ u( v, Z! b# q% C
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
, y: W' Q) b: y (floor((pycor + max-pycor) mod grid-y-inc) = 0)]. g% }2 T/ M- A+ C' C# h) V
set intersections roads with* F4 q; S. {- U7 I
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and+ ?% l; ^* |) q3 l. D
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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: k, X. ^/ ~2 y ask roads [ set pcolor white ]# u4 P) C! E2 l3 w4 z9 [
setup-intersections+ J0 t3 ]( l0 d* O. I9 I
end' _9 { u9 O2 _! s4 F
其中定义道路的句子,如下所示,是什么意思啊?
) @1 V9 J5 w( @; m) V set roads patches with
7 F1 m5 e9 c" q! d' l B5 J [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or1 S$ I+ H: o; P) a
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
5 q! e; p5 g$ E( F# ~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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