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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。
% C: X0 n, c- S9 wnetlogo自带的social science--traffic grid这一例子当中,
& u" ]% I5 X: F* Y; F9 Kglobals
' }3 L2 c/ v( R[
% \8 I. v' l6 H: k, O, D# P  grid-x-inc               ;; the amount of patches in between two roads in the x direction- e9 j" G# Z  P
  grid-y-inc               ;; the amount of patches in between two roads in the y direction
( V) f! Y5 Z6 G: @; R* d6 T& O, c  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
& |. K4 v+ F+ X5 N% x                           ;; it is to accelerate or decelerate
* H5 q9 O0 O5 z/ l  phase                    ;; keeps track of the phase
! f# E5 C8 Y5 ]  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure- T& j. \3 N  W) l  f
  current-light            ;; the currently selected light
9 ~1 k9 U/ Y( i1 T
; j% m# e% g) h8 k( U2 b  ;; patch agentsets
! p* ]9 ^8 \! i9 e* W! y$ A  intersections ;; agentset containing the patches that are intersections( E. ]1 l" R  o1 @4 x6 @$ E
  roads         ;; agentset containing the patches that are roads7 H2 B; H. O/ H; B0 w
]
# n9 y& H& @2 f: [( P: B3 {! r  |# Z( A6 D3 i& n0 u/ M" e2 B
turtles-own
/ C4 W3 e5 C. p1 v: ?, T[! P  l4 q) H# |' K: o5 x5 y
  speed     ;; the speed of the turtle
9 x( a9 K# H- y1 H- U  up-car?   ;; true if the turtle moves downwards and false if it moves to the right3 X) z# @- A. j5 r6 J! Q
  wait-time ;; the amount of time since the last time a turtle has moved
# ]7 z( x6 z9 _* []; W8 Q! r2 v2 A% x% g

1 T) _4 p" u# T! s6 W! ]- t- |5 t# rpatches-own: @' Q3 k0 P) e- [1 C
[
0 W2 M1 @- i/ o2 |, W, [" x5 D  intersection?   ;; true if the patch is at the intersection of two roads7 y5 {/ m5 v2 D
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
8 E; K1 `. w( x/ h$ e; k! u  ]  o                  ;; false for a non-intersection patches.
5 O5 _+ e2 A: u0 _8 v3 ^7 O% o  my-row          ;; the row of the intersection counting from the upper left corner of the
  a. `) h1 I; q7 ]% A                  ;; world.  -1 for non-intersection patches.' p& H. N/ x' j  s# j0 f
  my-column       ;; the column of the intersection counting from the upper left corner of the
0 V* O2 h  N4 ~7 J' S                  ;; world.  -1 for non-intersection patches.- u; i' N' H: H( @4 T0 \0 L6 M
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
' c5 e7 J% K* C, v) B4 Z" F  auto?           ;; whether or not this intersection will switch automatically.; s/ ^% a& h' L8 B
                  ;; false for non-intersection patches.% P& ^, [: Y1 R+ D; W
]9 _  T8 G2 t( ?8 m0 l% i3 p0 n
2 s* C8 l, C, x; \7 z2 m( H
! D3 j5 o1 H; p9 j0 C! V1 K
;;;;;;;;;;;;;;;;;;;;;;
) f0 m$ m# m# C;; Setup Procedures ;;
3 k  m( L2 a- \) a;;;;;;;;;;;;;;;;;;;;;;4 y2 ~! l) Q! D! |* O
" ]6 K- [1 X$ B  g1 M  D- Z
;; Initialize the display by giving the global and patch variables initial values.6 I8 x1 N- F$ E% r/ X
;; Create num-cars of turtles if there are enough road patches for one turtle to
! W) F9 T" p2 Q4 p' o2 @;; be created per road patch. Set up the plots.9 K( i! c( d* v) w% i% a/ z
to setup
, a1 ]0 z7 n% s+ q8 {$ P1 A8 ~  ca
3 l5 {- I" G0 T) z, N2 T" e  setup-globals6 i% _& ~5 ^, o0 m
: g7 y8 k: g2 p! e- V7 Q& ?
  ;; First we ask the patches to draw themselves and set up a few variables: x- m/ ~0 v1 H5 f0 y8 O
  setup-patches
! f) v. h- h6 n' f. _  make-current one-of intersections5 i6 l% ^: e# O: P) D, c2 X* @
  label-current8 {! @0 h+ ]. K+ h
- T9 G: Q: e8 b9 m, z( |+ D
  set-default-shape turtles "car"
2 K1 h4 J! P3 ^6 `" Z( A6 R( G# E# D0 x6 F+ H+ O; c
  if (num-cars > count roads)
/ g+ h. f1 H" }0 Q# P  [, L% v. i6 }$ O' r2 I6 J& ]
    user-message (word "There are too many cars for the amount of "0 F* W# P; e3 J' r+ P, o2 g
                       "road.  Either increase the amount of roads "
: K; W" ^4 x8 A5 q; W+ J) q                       "by increasing the GRID-SIZE-X or "
/ g) Y, v5 n  R& _! f5 V+ z                       "GRID-SIZE-Y sliders, or decrease the "
% j8 |( z% p* u; D' u' X                       "number of cars by lowering the NUMBER slider.\n"3 ]1 [, \% G, c+ `0 a5 n
                       "The setup has stopped.")
- a, e- T' ?' P+ ?6 H3 H8 m7 ?    stop$ c- [: J2 s2 h* m% [4 [4 `
  ]1 f2 @1 h7 T+ E3 S! @
4 f& a. Z- i0 U( x7 y. S7 e3 v
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color# G! T6 Q$ x0 A& q
  crt num-cars/ B  p) h8 a! P$ Y% H( a; R
  [6 j4 z. V+ f8 D4 U) B
    setup-cars3 b6 M& f% A, d3 L' ~4 `$ ?
    set-car-color2 m  f% P2 E8 m3 c& K1 b
    record-data
5 f! U7 d2 B" `! {  ]5 Z1 U7 w# \4 q9 A
) x2 h; _- j$ e! I0 {5 O4 a
  ;; give the turtles an initial speed1 [+ @. M6 q( S3 X* N- h* U* p
  ask turtles [ set-car-speed ]
: N5 N+ z) S7 s$ N
- O9 F2 z& D, R1 Z  reset-ticks- A3 q0 I2 \* Z/ u
end3 d  r9 e, ?1 T; w3 l6 M7 F
) `  G9 Q; P8 H9 |( q( P( l$ @6 p
;; Initialize the global variables to appropriate values% ^- i  [% ~6 j
to setup-globals
; M0 J6 Y( [% }/ L8 w! O" M  set current-light nobody ;; just for now, since there are no lights yet
% x3 g5 c; P+ D8 g. D  F  set phase 0: X6 \$ l$ ?+ s: D2 t% s
  set num-cars-stopped 0' g) k6 ~* p2 d# V5 c9 U; H2 Z
  set grid-x-inc world-width / grid-size-x
& @) |/ K9 |4 g' T7 s8 v0 C8 v3 ~5 r% \* }  set grid-y-inc world-height / grid-size-y
/ u# ]1 Z7 ~% l0 o3 q3 a( K
4 L% J" @- h- \  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary& l3 O, a( X) K) M$ y& r
  set acceleration 0.0993 W7 q0 `" q. |! e5 p4 w" I- m
end: Z5 ]/ x: s; H; x

6 H, m6 _0 `+ T( r;; Make the patches have appropriate colors, set up the roads and intersections agentsets,' Z- {% g0 `- r! I
;; and initialize the traffic lights to one setting
' S5 T( Q6 R- T! f) Kto setup-patches
$ \' \5 A& P/ x- T5 F  ;; initialize the patch-owned variables and color the patches to a base-color
5 ~; n/ X  X. Y. G  ask patches
3 }# @+ K9 K. ~3 W6 g7 R# y: b  [) I0 k! {) `9 `2 n, p) z( B
    set intersection? false; e; T9 q9 a; @# b: Y; Q
    set auto? false1 j! a! x4 f' e/ u7 N
    set green-light-up? true
, |# b) Z5 k9 z- t* W2 E    set my-row -14 F) a- a0 \! D7 b: `0 G/ v& }
    set my-column -1
( G; ?+ J& I4 j( [1 p    set my-phase -1
7 F) o+ A( x5 ^    set pcolor brown + 3
$ N5 n* {5 Q9 B+ o* a' Q; M: `5 l. Q  ]
2 a6 {+ h! B+ z1 P' i  v. ?( S8 N8 a  e, _
0 u; F0 ?& N, B' ]$ |  P  ;; initialize the global variables that hold patch agentsets! T# G. ]' M! k
  set roads patches with
& o- E/ k' o3 \5 a    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or- i2 h6 Y( }2 t+ d7 O! O' ]) o% s
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
( i4 Q3 X2 `( D& F- _2 u3 H  set intersections roads with
! \) N/ x6 c; j! X    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
; Z) ^/ T( q2 \5 C    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 Q+ y6 w' _1 A# k
; k7 w$ ~3 U0 r% a& F+ r* G  ask roads [ set pcolor white ]# @) m% Q% ?; D; Y% y
    setup-intersections( i8 R0 q. V: A! ~# |8 A
end
+ \' U3 j  V; _* g+ K7 t其中定义道路的句子,如下所示,是什么意思啊?% ~: U& y9 A* {, {; @2 x+ b  m
set roads patches with
; a& Q3 a/ F2 l4 P    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
- y7 ~* T/ ~4 c+ W/ S+ _5 G    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
8 P$ ~: D( m( 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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