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[求助] 在看例子时有几个问题看不懂

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发表于 2012-6-20 08:59:43 | 显示全部楼层 |阅读模式
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。  ?% V( @4 e8 g8 g& z! {5 k5 `
netlogo自带的social science--traffic grid这一例子当中,0 g& P6 t5 p9 N/ m0 O
globals
$ z5 f4 ~) s6 z$ g0 f3 [* a7 T8 O[8 Y; r0 l, E$ I  s0 w- U. s3 r
  grid-x-inc               ;; the amount of patches in between two roads in the x direction. z+ ~# ?" R7 J
  grid-y-inc               ;; the amount of patches in between two roads in the y direction" F4 I: o; U9 E& P  g4 {7 x
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
1 k) l8 E2 }0 U. R! N& g$ A                           ;; it is to accelerate or decelerate' a- I' f: K! m+ R2 Q, J; g
  phase                    ;; keeps track of the phase
% j) a/ }+ U$ t1 D* H  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
8 I) l: q& p- n' C) a  current-light            ;; the currently selected light. L. f9 y2 C7 T9 g) _! E+ p

0 Q# z4 h1 F' _7 g& _+ m, ?  ;; patch agentsets3 U; \0 E# u2 {/ i/ Z
  intersections ;; agentset containing the patches that are intersections
4 h) N& r9 B) S7 w; w! q, m  roads         ;; agentset containing the patches that are roads
# B0 s7 a3 K. P. W9 ~$ K]2 X# B/ k  L/ ]3 d8 e- y

1 u3 E& p8 `$ t" n" qturtles-own
. C2 W2 r7 {- }! g" L+ E[
5 d$ Z  J3 U% ]8 ^; F! f  speed     ;; the speed of the turtle6 P! {5 Q- I1 C, u5 w! n
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right& h7 w4 R: ]* _; Y
  wait-time ;; the amount of time since the last time a turtle has moved. s1 @7 s$ i' r, c
]
& F( a* {$ i; \' g) L- G$ `: e! y) T( q7 y5 W! F
patches-own8 G1 Q! x6 ~$ }, r( u6 i' G
[" Y8 w9 X+ K- O& q
  intersection?   ;; true if the patch is at the intersection of two roads) f8 o) v8 F3 K* }, `3 j
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
/ h; x6 ^/ K' P7 n+ W; _                  ;; false for a non-intersection patches.5 W) c2 [- v( l5 u2 a( \
  my-row          ;; the row of the intersection counting from the upper left corner of the
& f% G3 s9 N8 @9 W                  ;; world.  -1 for non-intersection patches.8 M' ]: Y8 g0 E' f0 C% _( z
  my-column       ;; the column of the intersection counting from the upper left corner of the- |( T' y- A' ~( }% K
                  ;; world.  -1 for non-intersection patches.6 E8 n$ c6 U7 b' P' ?- p' l0 w
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
2 _) h& ?# @$ C  T- A. ^  auto?           ;; whether or not this intersection will switch automatically.
2 ~3 F9 I* ]0 x- C6 O) d                  ;; false for non-intersection patches.
% H: W7 C# ?- ]8 U! b$ S]; @6 _; l9 ~, D5 L/ m8 D( {5 [! X

; e$ P* x6 W( E8 h, b" K7 O, K7 T. P( f- I7 ~$ v$ A
;;;;;;;;;;;;;;;;;;;;;;( O4 Q6 N4 P$ t3 D7 M$ v
;; Setup Procedures ;;1 [" |  k' n/ L; F9 f: V+ w
;;;;;;;;;;;;;;;;;;;;;;
" A# w" C) o5 k3 A. y( [  K9 l! [2 j7 Z
;; Initialize the display by giving the global and patch variables initial values./ @9 o; K2 b  b; {
;; Create num-cars of turtles if there are enough road patches for one turtle to, f/ f9 ^" W+ L2 g6 t" i+ j$ I( R
;; be created per road patch. Set up the plots.
1 X2 u& l" T3 _% m) s/ ~to setup) k4 S+ q. s$ x5 B  z
  ca
7 C' L- s5 C$ Z: a% u$ u2 D  setup-globals
( ?/ h3 l0 J; e% y1 S9 [  c( N  ^! c; |  Z
  ;; First we ask the patches to draw themselves and set up a few variables
, @# \2 K  `' ^. n  setup-patches- j" \2 I8 _* o; |: K
  make-current one-of intersections
1 I* t( C0 y; i' F' Y  label-current" G. w# M3 c( K2 I/ `$ U: r$ n
; \& v( \2 @  ]( i: H8 D/ W, n" \
  set-default-shape turtles "car"( G. a7 g) K; d& ]/ F& |3 X, m5 L

1 X2 N* Z; `8 [" q  if (num-cars > count roads)
) u! N- W  L2 g  [% g% d" L/ I& s. @8 a- |
    user-message (word "There are too many cars for the amount of "
: Y2 \$ m6 R9 I                       "road.  Either increase the amount of roads "6 C4 G! C$ _$ y8 @! s
                       "by increasing the GRID-SIZE-X or "4 W# q9 Q0 c/ J
                       "GRID-SIZE-Y sliders, or decrease the "6 z3 e& D$ {4 ^8 G
                       "number of cars by lowering the NUMBER slider.\n"
: v* x4 n( B  y5 ?+ {; z                       "The setup has stopped.")
1 Z+ N7 n+ F% G+ I9 N6 ?    stop% C5 `1 i+ u# G5 e% ^9 ^' G# f5 o
  ]' K/ t; V% a0 {, x4 ?# f! m
% q8 p( \) r9 L
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color* E; p% w) [. {( L$ Q: ^7 ~9 T; s
  crt num-cars/ J7 h& v* K2 e8 B
  [# B- u6 R9 O/ g+ Q1 H9 h
    setup-cars. x6 T% @8 L- a% w  z4 u7 p
    set-car-color# y9 x5 W/ k$ B) u; }5 e8 b
    record-data
% ~6 H. L) w! S7 K8 w7 c' ]  ]6 _# a9 ~$ ^$ \( a) L: c
; A& Q# h! y% h9 k. `' d
  ;; give the turtles an initial speed# R% p! F" J+ |' [' ~
  ask turtles [ set-car-speed ]
; c6 p$ t+ ^  N4 M# O( U
/ M, O3 _3 f' N) g% @  reset-ticks
' g: P9 a+ ]4 g( S5 r7 Uend
' |( I9 a2 A$ s, U: j
/ k9 L) Q5 m3 I) \( y& ^;; Initialize the global variables to appropriate values- g( x$ c6 y( _; ^, U2 [4 M
to setup-globals
8 n# D6 ]% k4 Y  set current-light nobody ;; just for now, since there are no lights yet
3 [; W5 `# O# Y7 T8 J  set phase 0/ G! q$ K. m/ W, R8 X
  set num-cars-stopped 0( P5 ?3 @+ b+ B2 z1 Y$ v7 n- D# y( `8 \6 F
  set grid-x-inc world-width / grid-size-x& J. q1 u- G# N; b
  set grid-y-inc world-height / grid-size-y
) o5 j( F6 `: @. ?. R! s" }
7 J- D# V" o9 u$ ~, {5 s' B  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
. v0 {! ?: V) [: |& N/ |  n  set acceleration 0.099+ ?7 d- n9 H2 w0 N& L1 ^# X
end
6 D2 o9 i4 {, x2 i3 ?, s) A; @; Q( B
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,5 |/ C8 r( j" z  [
;; and initialize the traffic lights to one setting1 _0 X9 R) [, j+ G
to setup-patches
5 E7 \; f8 x7 J7 f  ;; initialize the patch-owned variables and color the patches to a base-color0 ]) {  J" o0 g( R" g4 C0 l3 U/ D
  ask patches5 o8 |2 e1 u% |  S% a
  [  G3 m1 a( ?/ J# F4 c! \' \
    set intersection? false, d$ m% H0 ^9 u- o
    set auto? false
4 Y" A* b: M( Y5 m    set green-light-up? true
1 m/ o- u- K! a    set my-row -1
# _. J' j6 p+ E8 J3 l    set my-column -1
1 n5 N4 ~  i' V  T3 d    set my-phase -15 o' m6 S4 O3 j/ J7 t% x4 z3 n9 w
    set pcolor brown + 3
) {; P. M7 i& q5 b  ]  d9 f5 X1 k% H" R' t. v3 f- U! V
" S/ x4 q: V* `) }6 `1 Z
  ;; initialize the global variables that hold patch agentsets5 e3 |; b7 R( p/ q& z! V
  set roads patches with7 d4 F% D6 ^/ V( N/ V
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
" f8 Z, {6 d4 g1 S    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]4 r, Y- W0 u& Y
  set intersections roads with5 t0 A0 [/ z" y, V0 k/ \; |1 U1 B$ D$ H
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and+ G% D  G6 g- n7 u: Z/ H& G" m
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]8 Z+ D- i1 P8 X6 z

0 E5 C' n: M+ M% _2 F+ Z* o3 r# c  ask roads [ set pcolor white ]
- D7 T; w4 m5 Y    setup-intersections- }# p. Y, |7 t% a% A5 {1 ~
end
1 p2 T% L6 J4 E1 f$ {其中定义道路的句子,如下所示,是什么意思啊?
+ N7 E, ]  X# J% \0 ? set roads patches with4 b8 H; D6 N, E6 S
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
3 ?- M% _0 H! E2 J: c( L2 q    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
& A" W5 k5 w& t, L8 a7 R# G+ ^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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