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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。
( S, |0 s; k8 s4 D$ r4 e  Y; s( |$ a* snetlogo自带的social science--traffic grid这一例子当中,) O% S$ ^2 K6 r# l4 N. O/ C2 D
globals' n( k" W0 h  A* ~
[- p- V, |' f3 `$ K! W
  grid-x-inc               ;; the amount of patches in between two roads in the x direction" D2 F. O; s% I# L$ s5 j9 w7 l% |3 B
  grid-y-inc               ;; the amount of patches in between two roads in the y direction
$ z: ?  R  F* A2 E0 m+ [4 X; U: @  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
- x2 t+ ]' i: O! t, H* Y) ~                           ;; it is to accelerate or decelerate. a  ^+ j/ `+ @! l
  phase                    ;; keeps track of the phase0 ]0 }0 B. G. _5 [
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
- m2 R% g. L  }( s% {# x  current-light            ;; the currently selected light
# V! d, O7 L+ U; |1 u5 a! H) a  C5 Y/ k) v; V( v! R5 |( l3 X% C& k
  ;; patch agentsets
" c' G  L$ J, K! R  intersections ;; agentset containing the patches that are intersections& ?- M6 z! U, T" i
  roads         ;; agentset containing the patches that are roads
9 Z; e' m) y5 `6 p; q( W]* p2 B% z4 y5 g- C6 t( N" G7 g# [

1 ~. Q8 O7 L6 t# p) xturtles-own* W3 U7 e0 x/ ]
[2 O  _/ [7 B2 o; K- p* l. t
  speed     ;; the speed of the turtle
9 J) Q! r6 A& r1 `3 B1 ~  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
0 t8 B4 a$ S% F' a/ }9 E  wait-time ;; the amount of time since the last time a turtle has moved
. C# s! P+ h  K, [( C]
, e. m  ^; c+ W% a: K; N, Y
9 N  d2 i9 G3 ^  ]2 opatches-own. O, D$ x4 ~  N. D: K. r& P
[9 X+ L2 b" m# O- b$ w$ j
  intersection?   ;; true if the patch is at the intersection of two roads! ~3 U2 e' x" x. q0 k& p
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
" z0 ]+ E$ N5 D( Y  P                  ;; false for a non-intersection patches.! a' N  l! {) N4 z+ f/ q( Y2 }
  my-row          ;; the row of the intersection counting from the upper left corner of the
& Z; a& U$ y1 F3 Q* Y. f8 E+ T                  ;; world.  -1 for non-intersection patches.) Q( Q' `  \- \% }8 z5 P
  my-column       ;; the column of the intersection counting from the upper left corner of the
. T/ u$ w5 x7 N6 z                  ;; world.  -1 for non-intersection patches.8 N+ v; \8 v1 ?- u
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
5 f9 I( ^2 q% o  auto?           ;; whether or not this intersection will switch automatically.
5 g4 R7 v0 A9 I; P$ e- j  u                  ;; false for non-intersection patches.. v! _& |# m) t1 P
], E  g$ f# F( S/ @6 ^$ I- \1 V
* b/ i8 x3 v0 B5 J0 M

: ?) k9 g: B5 ~# j;;;;;;;;;;;;;;;;;;;;;;; p% g( S/ f& B
;; Setup Procedures ;;5 U* K) a% J  p, S  K9 T
;;;;;;;;;;;;;;;;;;;;;;# [4 Z2 U: r2 U, h6 O7 C/ n

6 s. M! s+ r/ u$ v  c/ d;; Initialize the display by giving the global and patch variables initial values.1 Q) s7 G3 K6 C9 W
;; Create num-cars of turtles if there are enough road patches for one turtle to
( |' e6 {9 R! t4 K;; be created per road patch. Set up the plots.; Z+ x$ q) C6 _
to setup, i/ v! O. N& Y) ~3 M
  ca
9 ~% p$ p5 k: P# o0 g5 N8 ~6 }: M  setup-globals
2 b% m5 b% s% C# t0 p" a+ P
& O' g, X! \; g8 \4 ?  H+ q  ;; First we ask the patches to draw themselves and set up a few variables* w& N# ?  `; B# Y, M
  setup-patches
% m2 u2 L" |1 b: L* G* S  make-current one-of intersections
4 T+ b  }4 d& ]; v/ h  label-current
/ l; Y2 z+ J$ N& K0 g9 k* ~' J% k$ n4 R
  set-default-shape turtles "car"
: x" c% [& a  h5 H3 S! t; C% P! M* C; T
  if (num-cars > count roads)# y# b! u  T. W# l# O8 Z% E
  [1 X4 @6 F. T$ f' l  ~
    user-message (word "There are too many cars for the amount of "
" x2 m' h# }0 `& f1 \% R                       "road.  Either increase the amount of roads ". n! t3 z; i! N+ o0 o6 k$ i
                       "by increasing the GRID-SIZE-X or "# T9 q% d6 V# l
                       "GRID-SIZE-Y sliders, or decrease the "; @9 |1 x" O6 L4 N* m! T
                       "number of cars by lowering the NUMBER slider.\n"
% T& X( b( R1 s0 M1 t7 T8 q                       "The setup has stopped.")2 U* U! U1 c  M5 B7 R- U
    stop" ~3 U+ x7 a1 j7 H
  ]4 |) z# c; _' i5 d
& \. U4 f6 Q( U
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
* d7 v5 f$ a' R8 v  Y% r, @  crt num-cars
5 I, J+ y: X8 s7 ]  [( ~% w, F" Z7 x4 z% w( o
    setup-cars
* C$ s- Z8 Q* ~+ Z. r3 x) y3 K    set-car-color( X$ U$ [# j! u4 F* J# X6 z
    record-data6 k* f  O7 A- a9 t1 o9 {* U
  ]
" L1 i2 h% C/ \2 ^3 o. P! s& f+ j% G: A4 Y
  ;; give the turtles an initial speed( b* \! q. f. s( U. Z# ?/ l
  ask turtles [ set-car-speed ]8 y2 U8 R5 \  p* T. \6 F* O

* g* F5 g! o$ [5 l  reset-ticks
- _5 D  ]- `$ z! t! h: N5 yend  l" {# ^0 ?* W' {; i
" X  s5 R  J+ ]4 H
;; Initialize the global variables to appropriate values
$ R) A  B. ?0 j  b2 nto setup-globals* j! G* @1 k8 J' O# ^5 l
  set current-light nobody ;; just for now, since there are no lights yet  A, d& X& r4 i1 u
  set phase 00 G. U& e" y  {8 ?
  set num-cars-stopped 0. Z* L( @. W/ ]: r/ \
  set grid-x-inc world-width / grid-size-x
* q! g  v: G7 r$ h# a* y  set grid-y-inc world-height / grid-size-y  p1 r7 p. r: S; A
2 I+ Q* x$ b8 ?" w2 j( Z8 k
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary2 w  X( y( v' T" Z. a) W1 s1 e6 J
  set acceleration 0.099
+ ]. F6 i. F8 k% P2 ^; zend
) p! C( c- g5 Y" a! l3 [3 b% d4 ^3 x. S8 n
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
' [3 v# J& h+ }$ b" b;; and initialize the traffic lights to one setting
3 ]# |9 F1 R  {, M3 O% @to setup-patches
+ V# S& [8 Y: ]0 H! i. d  ;; initialize the patch-owned variables and color the patches to a base-color
, i3 C: s- Y  R! @3 Y1 p" w  ask patches3 a, j3 B  [5 q# H5 N  N& @  s
  [" Y+ W/ W& \/ h+ e; n) Y6 ]
    set intersection? false
9 Z- A: B" J( @    set auto? false
5 A1 o7 f/ @, N% [# `/ W* b) N    set green-light-up? true
/ |2 m" ~( c1 _/ @, P    set my-row -1
" t& ~/ _+ l3 f- G( P" g  _    set my-column -1; _; ^# l. V, q
    set my-phase -1
  [  |/ j' p* J    set pcolor brown + 3
  L$ C0 h. W, m# Y* |0 r0 T9 r  ]
& U$ k3 A3 Q' X2 E& [
/ n9 T* g: T' C  ;; initialize the global variables that hold patch agentsets
2 \) ~  @! F& M2 ^, q; G  set roads patches with' s" M# r1 T* v! B" s6 x: Y
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or4 ]+ ~+ j  z; c* d& N
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 w+ G8 Y4 f3 T% `/ l& [/ K; p% e1 ?  set intersections roads with* _- q! l) O) B, \# L( Z2 P
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and! Q6 v' D& e0 g  B4 ^  I( R! i9 L! X
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
; b, {$ M4 V# t8 a. \9 t. \; d- C5 _# D# E+ a0 ]( R8 Z& Z5 `
  ask roads [ set pcolor white ]: n$ [" [# L& S( l( t. n
    setup-intersections
' C3 o$ M* ]' o" B& m1 E4 bend
' h- S5 n5 d* \其中定义道路的句子,如下所示,是什么意思啊?* k4 U9 Z5 `% P0 Y
set roads patches with2 O. ~' z; S9 t/ ^
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
2 G7 q2 v+ k/ @, {    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
; `  }+ Z- c# k; \. Q1 h: C3 \% 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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