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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。& _# U2 M0 @9 |. g+ U8 z9 m8 T
netlogo自带的social science--traffic grid这一例子当中,
; }$ N. Z- N' u$ _% G7 ^6 @$ d$ ?globals& t* n/ s6 l4 Y3 d
[6 a" }% K* Y. `& n( K- ]' @) a. Q
  grid-x-inc               ;; the amount of patches in between two roads in the x direction* K2 V6 y' _) U% l8 N
  grid-y-inc               ;; the amount of patches in between two roads in the y direction
% R; Z& p7 o$ c% |6 p0 A" C; v  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
) C; Q: I, x8 ^2 o                           ;; it is to accelerate or decelerate
* v- {0 Q7 p+ p7 c) a  phase                    ;; keeps track of the phase; n# f- T" F8 W. W/ p
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure; E% v0 e3 v8 J
  current-light            ;; the currently selected light0 S! n, w+ H& x$ p  q
  `  i8 h% }0 t- @. f
  ;; patch agentsets
9 A& {; _5 f5 G$ d  intersections ;; agentset containing the patches that are intersections: A+ `& q/ o: i/ C# U& O  H
  roads         ;; agentset containing the patches that are roads$ U4 Q0 W: q2 Z/ G5 h
]
/ ^9 g; q  v8 o  i
: k+ X, o* a* ^- Oturtles-own' A0 {# N" J  u# `  y# I4 O
[: d8 W" m& h1 x& l; d2 d9 a
  speed     ;; the speed of the turtle8 l9 Q( [! s  f
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right1 H- b9 P7 Z9 e+ y# a
  wait-time ;; the amount of time since the last time a turtle has moved# s, [- u/ k- u; C
]
+ K. a+ X+ n0 r; E" R  _+ k9 n6 H5 I; m5 d1 q: T% D  e7 a5 d
patches-own% M: c( W) F6 P0 @. V
[
! j3 ]; P" S2 r, I8 Y  intersection?   ;; true if the patch is at the intersection of two roads
2 e5 t, ^# |1 l' E) e  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.8 @5 y" u/ H5 t6 Z8 [5 z
                  ;; false for a non-intersection patches." {3 B5 I+ b  @1 y3 Y) K
  my-row          ;; the row of the intersection counting from the upper left corner of the
5 C. Z! V3 o* w0 l; I                  ;; world.  -1 for non-intersection patches.- y. K: n. G3 i) l
  my-column       ;; the column of the intersection counting from the upper left corner of the' T- {5 J3 A/ r0 G" C
                  ;; world.  -1 for non-intersection patches.
, u  `5 a' P- U) t  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
+ h; Z1 i: r3 [  auto?           ;; whether or not this intersection will switch automatically.5 H: q- I9 h! n  ]( _) k
                  ;; false for non-intersection patches.
5 ]# |; O& E+ b# E7 D9 J& K]
# K+ z; x( i- X' N( }! q: k& Q$ C" |+ o" `+ p1 F7 r
! B% E0 M/ i2 U* Y% [" X8 A* i: N9 r
;;;;;;;;;;;;;;;;;;;;;;, }! F6 x( G. ]+ _# U
;; Setup Procedures ;;
7 G" u1 k9 {. b- u& C: {;;;;;;;;;;;;;;;;;;;;;;' ?8 [/ f6 \& U  k' k( J

/ ~5 W, `' C8 P  T2 A;; Initialize the display by giving the global and patch variables initial values.
- t) v# U2 g, L;; Create num-cars of turtles if there are enough road patches for one turtle to" |* F3 [. p. y( l7 t
;; be created per road patch. Set up the plots.
) e& M! L& y" v1 V# Y: o& Tto setup8 ?0 ?3 O2 T( I$ P% e4 P
  ca
9 p& \# ~8 Q4 d$ B' I& L  ^  setup-globals3 E6 H+ Y: [6 I' e. @8 d

+ ?6 L3 V: M& ]3 I- Q  ;; First we ask the patches to draw themselves and set up a few variables
" n0 S4 P/ l% p3 ^6 j( G  setup-patches
* n: W4 I( {+ G- K# r  make-current one-of intersections
1 t* j3 p# v  `3 C, G# H; Z  label-current8 q! H" `% N8 g) u2 y
4 n8 u* T7 u4 u1 f
  set-default-shape turtles "car"
% V3 q  D* g: @, n( c
1 ?5 K  Q6 c- S4 M3 T1 g  if (num-cars > count roads)7 }0 u* W; \, \7 {: @7 }5 t" c
  [+ K& r9 r1 i# U9 Y7 H
    user-message (word "There are too many cars for the amount of "- r- z- ]& n" J, z# }6 g0 [" H
                       "road.  Either increase the amount of roads "! E/ n; J8 l" ^. D4 V7 Z, b
                       "by increasing the GRID-SIZE-X or "
" z) p$ [) e, P$ n# k                       "GRID-SIZE-Y sliders, or decrease the ") k, Z8 r& N/ L0 G; f2 A
                       "number of cars by lowering the NUMBER slider.\n"% T. W6 T; S' s3 K$ L; }5 n1 K  H
                       "The setup has stopped.")
+ ]3 s, Y0 ^1 j    stop9 s* g7 W2 {% c# Y; l
  ]7 Q# i  |' ]4 |5 V8 N

+ [5 U9 b  }6 X. ^+ w# z* o  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color7 j: o2 [3 O6 ^
  crt num-cars: C: j) `7 b: X3 D' v, E
  [# c( u" p# ]$ V2 [
    setup-cars
6 @/ F. {& Z1 F+ ^8 f: ~    set-car-color
" x' i3 I' o- `. Y    record-data
' t3 f1 Y5 i* c5 x% [; Z4 Y' T; I  ]1 S% X) e8 l; a0 C* e1 I; p
. J: K) n: p1 U  l: b* P% `
  ;; give the turtles an initial speed4 u* k( z9 ^% {  z/ @3 f
  ask turtles [ set-car-speed ]& c5 M9 z$ O% H% p

, |* e1 V+ L% t$ Q9 Q; T  reset-ticks
4 ^3 m& J7 D- y+ pend
9 \9 |4 Y( `  `' V& ?" n' Z
! w0 A) J/ G5 W! k: o- n5 h3 \;; Initialize the global variables to appropriate values# n; I8 I  m6 u9 ~) `7 e/ ~
to setup-globals
  i5 R* u: y% Q: a0 \4 R  set current-light nobody ;; just for now, since there are no lights yet' q5 f8 G# q9 |7 G
  set phase 0
5 @5 g9 f1 `# }9 L  set num-cars-stopped 04 w7 x# U) ?8 s7 u2 s
  set grid-x-inc world-width / grid-size-x
% y; `7 |7 I3 u2 ^9 |  set grid-y-inc world-height / grid-size-y
' n5 p. x9 g! \
& M5 c3 D2 l& ]# P  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
9 _, h8 X$ t; k  a  D$ H1 P6 R) c  set acceleration 0.099
1 }4 L4 {4 B0 c, O$ B9 g1 Iend
& k( b3 h4 X9 D$ t8 Z; X. O& M' a5 ~) h
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,. G! ?/ u- G) [2 m3 {
;; and initialize the traffic lights to one setting
" p& W9 T! Q: J- vto setup-patches3 m/ U& f) U6 `1 I0 j# _
  ;; initialize the patch-owned variables and color the patches to a base-color' E6 U9 h, A( \
  ask patches
0 S2 v- Y+ S# h, c% e  [: t) L# z5 b- }3 a9 Q
    set intersection? false5 N; I- F& U7 u7 u7 x3 I
    set auto? false
% ^0 i+ [: `0 k: p; w( Y    set green-light-up? true
* Y& a3 K1 Y0 F, N    set my-row -1: g5 Z8 D! H# I. i/ W
    set my-column -1
/ G, K, m6 c4 c( \& I5 a; m2 m    set my-phase -1
  A) n3 t/ [* Z- ]    set pcolor brown + 3
  s4 b( x6 N% Q5 X/ s7 R  ]
# B: I; U0 `- R& o* R& }# Y3 ?% b( Z4 ?
  ;; initialize the global variables that hold patch agentsets
3 k/ b0 R1 N8 V  set roads patches with) J. ]: n2 `7 P# w
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or) L. V& f1 A# Q! I
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)], j2 A' ]0 A, U1 Y4 r; I
  set intersections roads with
. ^2 p! N( X2 L1 {2 h; C% p    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and9 }- o1 g; r% ~
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
; J0 }) V+ `. g% R+ t4 k; q. P0 Z% X  P/ S4 I- A9 H6 \6 g$ D: r
  ask roads [ set pcolor white ]
3 A* M# |$ Z+ \6 x  A7 Q  S1 u( b    setup-intersections
1 v# R: ^3 Y, |8 T& Oend
: L7 X! t6 A1 U+ [- ?% b其中定义道路的句子,如下所示,是什么意思啊?0 [( D: Q* p/ V% \! Y3 w8 L
set roads patches with
2 E* g7 x; L/ _, h) f( s( M    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
+ _2 M8 E& E' z    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]7 I5 c) ^: Y+ H" 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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