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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。
/ e9 g& U; ]8 C! B) ]' @netlogo自带的social science--traffic grid这一例子当中,
  y3 ^" F& k9 g+ s* {# qglobals" l+ o$ N' `- x
[$ @  T$ E  |; N0 M6 B9 f2 C
  grid-x-inc               ;; the amount of patches in between two roads in the x direction" D1 H; E/ f' l0 H6 f
  grid-y-inc               ;; the amount of patches in between two roads in the y direction$ ~5 c* M: I. ?7 X. h1 t
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
8 _! V/ I- }) F3 |4 L- |- H. _8 b0 D                           ;; it is to accelerate or decelerate
( |# R( h/ Q* l0 d' N: M  phase                    ;; keeps track of the phase
$ F! k9 P  Y' e/ x3 [, B  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure$ T. l. c# M! R& f/ M6 E  G: Q
  current-light            ;; the currently selected light
( c2 Q! g! [. a0 j
8 Y+ K& o; P2 r  ;; patch agentsets4 n4 J! _$ q; w" p+ Z3 @
  intersections ;; agentset containing the patches that are intersections
) a$ `$ @: @# S- w; F# ?& H7 N  roads         ;; agentset containing the patches that are roads# o6 @; {& ]( z% c& w0 a; ?
]) o- D/ }- p1 `+ L
& S9 ?4 e( f% k; S$ `1 n& s
turtles-own# |$ ?- T3 x6 B, W% @4 U
[
- V% e$ D8 [5 I6 I  [% L/ f  speed     ;; the speed of the turtle& X: h% n, L( Z/ ~/ p5 ^
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
$ G$ p  V, r3 h+ @1 Q  wait-time ;; the amount of time since the last time a turtle has moved
+ E9 ^/ O0 l# t]
! Y3 Q7 R! q6 e( C/ l2 L4 Q( x3 q* T) r+ D, a4 c0 X/ Z& t
patches-own' A' c& b' {( u7 J$ d
[
, }/ f' G& ^3 a! e4 c! `7 Q4 b  intersection?   ;; true if the patch is at the intersection of two roads
; L% a& L) o. m& M- u  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
3 `1 W# @0 G. A* \                  ;; false for a non-intersection patches./ u1 C# [6 u; U( \: b2 X! O
  my-row          ;; the row of the intersection counting from the upper left corner of the
, b6 x/ {( _; r! J                  ;; world.  -1 for non-intersection patches.6 [9 Q  Q7 ?9 ]/ P
  my-column       ;; the column of the intersection counting from the upper left corner of the" U- M1 g2 S' k
                  ;; world.  -1 for non-intersection patches.
  A9 Q( m' `4 j9 G9 M1 B  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.: j8 `1 A, l  k: @% c
  auto?           ;; whether or not this intersection will switch automatically.
! M. b( b$ ^! i+ R                  ;; false for non-intersection patches.
0 h4 `( m5 z4 |7 {$ X! ~]1 G8 `- t, `. p3 h

, [; R- p1 v+ v7 w+ H# z1 e1 s: c; C. x. D$ L! T6 H6 j. V0 ?
;;;;;;;;;;;;;;;;;;;;;;
8 g( L/ X7 s/ s4 X( G3 J;; Setup Procedures ;;. X5 x$ U9 o7 c  a, R1 _" I; V, v
;;;;;;;;;;;;;;;;;;;;;;( ~5 W; q8 |# _, z, u7 C

7 `1 Y4 v4 [' F- n# I;; Initialize the display by giving the global and patch variables initial values.
; ]  i7 ^& z* ]8 j; D, U;; Create num-cars of turtles if there are enough road patches for one turtle to
- m# J( w% O. g% s" _;; be created per road patch. Set up the plots.& b! A$ o" B# i9 C
to setup9 k7 \7 I; A' m# S9 e% x8 v) N* h
  ca. N& ~) w7 x5 X0 X5 K9 h4 R6 h
  setup-globals3 L% |7 l( z6 X' T: h+ }9 ]& y

- x( V9 c5 V! S& M8 \3 r  ;; First we ask the patches to draw themselves and set up a few variables
0 O9 s; f# V. ^3 m8 ^! z1 |  setup-patches
( Y$ |5 i' m& n7 K  make-current one-of intersections. {1 v) T9 ^- D  o( w
  label-current
& X9 w* x5 n0 `( L  s& c2 c$ B
+ |9 c1 c9 D3 S! e) F8 D4 ^  set-default-shape turtles "car"
  D1 F; U# x9 O2 f% q6 b" y( x/ \: d$ y* X/ N2 x6 j
  if (num-cars > count roads)3 o; `6 R8 ]- a) x. ^: H& F2 ^
  [
: u# {" m) y; s, W5 E  D( [    user-message (word "There are too many cars for the amount of ", ~6 {' [  W* X1 K; J7 P( v# @* ]
                       "road.  Either increase the amount of roads "; Y' g" |5 M8 `/ w1 P$ S; Z2 s% O9 t
                       "by increasing the GRID-SIZE-X or "  e# E+ |& p* L! n5 ]
                       "GRID-SIZE-Y sliders, or decrease the "! {- g0 v2 K4 |+ B$ V# s' a
                       "number of cars by lowering the NUMBER slider.\n"
& h- @/ n0 `  r* B2 g/ i                       "The setup has stopped.")9 a2 I; _" a) U7 i( b' J
    stop
) e8 ?" ]4 ]& L  T9 x  ]
& g% `2 R7 Y% R. N! E7 r( u2 Y
; {9 T3 k. A# g. I  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
3 M5 }3 \, i6 G1 d- i4 y% \  crt num-cars6 T) o# I* V) d8 s
  [0 {4 m# B# p# v; L) Y- Z
    setup-cars
5 p& J; h$ B1 N! L* c    set-car-color" l4 U, n/ b( v1 j5 i
    record-data
) h% j/ m8 {  X' o  e. t# u  ]% b+ j% o" q3 |( [2 Y

" P2 d* m4 ^7 A8 {  ;; give the turtles an initial speed$ V; U- |  g6 O* }. A) T
  ask turtles [ set-car-speed ]
5 V3 Y  f- [. d8 e" o  N
- o6 `6 p. V7 F' ~8 g3 v( |  reset-ticks( X( L, }  c* ?3 l' Y& E
end
" A; C! u0 ~) X" g# c' ?! x; w
, Q* P$ Q3 _0 };; Initialize the global variables to appropriate values
" v3 J8 [$ h6 Yto setup-globals
7 {5 y$ ], j; z1 ~  set current-light nobody ;; just for now, since there are no lights yet' q# n$ r3 q1 m* I. B
  set phase 0
  c, v3 A, L4 w4 M5 D7 t7 E  set num-cars-stopped 0
1 |$ o9 o8 \( e. m3 h  set grid-x-inc world-width / grid-size-x8 n# g0 @' I# ]3 Y8 k
  set grid-y-inc world-height / grid-size-y0 v- I, b4 w& N5 l6 }9 P
( k8 E0 D2 T8 }7 j+ f; `
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary# V0 j* u: b+ {. F) J5 ?8 B! p3 X5 I
  set acceleration 0.099& P+ [5 b/ ]9 L& S
end
+ ]3 J2 F8 }2 q9 Q" p% h) ^
/ D. p" u9 ]$ k# U' L;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
! H) E8 r8 e0 p0 G$ c;; and initialize the traffic lights to one setting
  B1 i  r$ I) h9 K0 D) l5 Tto setup-patches+ `# X% K3 F5 b" Q( h# \4 `
  ;; initialize the patch-owned variables and color the patches to a base-color9 H4 @9 d9 I5 v; R" [. g  ?
  ask patches# w% }3 I1 W. y) W! G4 b9 B
  [
8 H) g. [5 s3 c5 Y% z' j    set intersection? false" D. j+ e  c# B. p
    set auto? false! w# Q5 f' A( Y5 p/ b5 l4 r
    set green-light-up? true* W6 V( B) W& a& a  L" s
    set my-row -15 R5 F7 d- G6 y. b! @8 h/ j
    set my-column -1
& y  H& W! c5 h( `) o$ I* V3 z( u3 }    set my-phase -10 [3 N& I5 m* a+ y' U
    set pcolor brown + 3$ D8 |( t* Q$ i& |
  ]$ f2 i  L  W8 C
% _* i7 s+ T# ^- d' b
  ;; initialize the global variables that hold patch agentsets
" }. N" M- e3 M$ `, s' f8 F  set roads patches with. J: u- [! l. X' @
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or( u0 R: ~: o- a5 ~, D$ _) Y# p
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]9 H9 q7 |+ ~  T1 ]
  set intersections roads with( X3 m( G" i% G8 j4 J- q
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
) p7 y; K/ M, @$ m6 W( K9 D( K, h    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]$ ^. M: s. s% y+ `) A
+ c* T# n( Y% y" C" Y) U% b0 F
  ask roads [ set pcolor white ]
5 o$ ~5 g4 J$ j: T! W    setup-intersections
. T/ P! t/ v# d, N. P- cend
' x5 m) S3 k: @* M' ^1 ?4 f其中定义道路的句子,如下所示,是什么意思啊?
% U8 ^* Q* s( i$ H$ A3 Q+ f set roads patches with1 W) q! d0 a# [' X2 O6 Z# `
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or$ ^- c7 S$ V3 X: r6 L* F7 t% t9 s
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
  s) K' q) U2 ?  u% s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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