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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。
/ k9 `  l- Y8 F9 R$ C1 Gnetlogo自带的social science--traffic grid这一例子当中,
4 `8 v% D. V! @3 {" p; d# g: z0 Tglobals7 m/ _7 H) L( t$ K7 M0 N
[
, e4 V6 ^4 Y$ Q, w  grid-x-inc               ;; the amount of patches in between two roads in the x direction
4 r5 F# ~+ Q7 Q1 Q2 O7 q1 u* t+ T! O. J  grid-y-inc               ;; the amount of patches in between two roads in the y direction8 p) y) ?$ K  M3 r: V
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if8 {5 m0 ~. [/ F( Y( X
                           ;; it is to accelerate or decelerate# u$ U. k! A3 p. z9 U- M
  phase                    ;; keeps track of the phase5 j. l3 t& ]$ K2 [5 d$ B
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
6 s' a" [7 I7 n; ~. S1 Z' o  current-light            ;; the currently selected light  s& k& X% J7 R7 r
9 y1 p& \4 \+ g! G
  ;; patch agentsets
; V% j% N: v0 f7 w2 ~1 f3 G( n6 x# ?  intersections ;; agentset containing the patches that are intersections
& ?" [2 a' ?5 S6 h% \8 d( f2 \  h' J  roads         ;; agentset containing the patches that are roads5 T  y; z9 L7 L) g& ~/ j3 P
]9 ]: Z' ?; e- O+ ~2 q3 q; D
& _' b2 d( H) M9 ~( P
turtles-own1 u  B$ M8 L4 N9 v8 X* \0 o
[& Y  V% Q1 m; `
  speed     ;; the speed of the turtle
0 `) D  K- Q3 [: g7 p  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
- n0 S' O( w1 g  P7 s& B  wait-time ;; the amount of time since the last time a turtle has moved& @! b# {- z$ f
]
! W2 D  Y* M. A. ]1 u/ |$ ]* j% f0 ~* P5 {% `" k
patches-own3 [5 i) E+ z* ^; `) ]6 t7 m3 L7 G
[
% K1 _  b& T" X  intersection?   ;; true if the patch is at the intersection of two roads
$ _5 r6 s* q: x  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.6 p& ^3 N# R. Q* i0 `( E8 ^0 H
                  ;; false for a non-intersection patches./ j+ m" Y; B- B
  my-row          ;; the row of the intersection counting from the upper left corner of the# d% Y" T' n$ H1 T0 a
                  ;; world.  -1 for non-intersection patches.
4 n( N* o: E( w- `; b  my-column       ;; the column of the intersection counting from the upper left corner of the
3 v6 q/ G) f' m1 `4 `# S                  ;; world.  -1 for non-intersection patches." ?& M+ H$ z. Q3 J2 b
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
$ K- _( b6 [4 v# N- F, S: x" m  auto?           ;; whether or not this intersection will switch automatically.
3 l+ {7 V) b9 P                  ;; false for non-intersection patches.# r4 e$ B9 N6 g7 i
]1 [9 j4 g9 J2 i4 Z

0 U$ ^" s1 P4 m& F, d4 R& J9 J0 g8 W5 |( T; |/ F
;;;;;;;;;;;;;;;;;;;;;;0 ?2 f9 q/ D: n! @. G/ R3 r
;; Setup Procedures ;;( H" h: f' |' h" b
;;;;;;;;;;;;;;;;;;;;;;2 @4 q) n/ }3 |. d4 t# q( a

9 J. [, W/ q# m' x* z;; Initialize the display by giving the global and patch variables initial values.
- q' O" @3 ~! Z;; Create num-cars of turtles if there are enough road patches for one turtle to; W* L! v" F1 F3 u, \* j
;; be created per road patch. Set up the plots.2 K; ^$ b0 C1 c6 A. N
to setup7 m# U' e0 \( B3 V6 O
  ca* U4 @. t/ ]" c
  setup-globals4 s% C9 C6 S8 d
7 `3 l. \, x9 {) m( _
  ;; First we ask the patches to draw themselves and set up a few variables
9 Y8 O" v, q) m& V  setup-patches) H; ^6 y) b! i0 ]* o# @( {
  make-current one-of intersections
# L9 N  i4 K1 r  label-current& B- r8 ?  F  D3 Y
9 Q0 V5 ^# e4 M. ?1 W' e  t* W" @, B
  set-default-shape turtles "car", z, q) h) T- x# E( `
0 P; B+ C& e; _. n
  if (num-cars > count roads)
: I& e3 O- {$ |8 q- P  [
* S! w* k9 Z! s, ~8 q4 C    user-message (word "There are too many cars for the amount of "4 a0 C( L! F  s/ a# L8 U4 y3 m
                       "road.  Either increase the amount of roads "
& Q, C+ O( K8 l3 i3 q7 O* E                       "by increasing the GRID-SIZE-X or "
2 c8 {6 ~( @8 ?" k                       "GRID-SIZE-Y sliders, or decrease the "
! F  D6 ?3 L2 B                       "number of cars by lowering the NUMBER slider.\n"% Z6 J! ]0 X( l2 v  W6 L5 E
                       "The setup has stopped.")' ]6 ?/ _8 E7 t  p6 I$ t" V6 f8 i: f
    stop; H! K) ~: K/ ]( E$ p' h& R4 m# W
  ]+ j5 r5 Q3 P+ A: H# d

$ l0 p4 A2 K0 q  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
$ R; x+ S5 \/ O) u4 b) j7 G  r  crt num-cars
. n% M7 {0 P, b  [
- k" ?, n. r$ x3 u0 b    setup-cars
! ]: F2 |( f. m- m    set-car-color4 u& h" l3 j# {6 o8 E
    record-data
, h' D, ]' @7 O+ r( f  ]
: a( ^( _9 o& F" A; A9 {  R! L- C1 T" {8 b8 G
  ;; give the turtles an initial speed0 f9 B$ m! A: h/ A
  ask turtles [ set-car-speed ]
  y+ W2 Z8 ~; O% S9 y1 r) k3 i/ i; F
  reset-ticks
7 {" O/ e2 f! z, aend1 X! b- |7 B2 C" j" w: e

8 H- J/ k' E) ^  A;; Initialize the global variables to appropriate values
7 t9 S& H* W* M* Ito setup-globals9 w! Y1 `4 A& e$ f2 M
  set current-light nobody ;; just for now, since there are no lights yet
; _: E+ J$ P, E, M" t% z1 t  set phase 0
# W* Q+ Z7 C7 [' m) ~9 F$ _# |  set num-cars-stopped 09 o' }" R) ~' @7 j# O& C
  set grid-x-inc world-width / grid-size-x" I. y5 H0 T- ]" o7 t* F* h1 K# M
  set grid-y-inc world-height / grid-size-y% _; Q8 ^( F+ c2 j# @- b/ ?5 B% k
; c& ]: Q! A# d; u. }) W$ W
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary1 L% \& B8 i1 @' @
  set acceleration 0.0994 M! U# G7 p8 F* S1 b, m6 ?
end
7 E0 V6 S. z1 n& y
7 a4 b7 u& Q0 r5 @! Y& i1 x;; Make the patches have appropriate colors, set up the roads and intersections agentsets,; e  }+ Z; A2 B/ O* p+ e
;; and initialize the traffic lights to one setting
* n3 |4 [# F$ a0 v# K# Ato setup-patches3 o( t8 y8 n6 h$ G; h
  ;; initialize the patch-owned variables and color the patches to a base-color
" a' z1 E! z) B3 B5 P: d. h  ask patches8 `. Q$ W8 v% M- }; F
  [
! H1 b5 N* g& P4 }! k* ^    set intersection? false  z6 t4 R: {$ x( o
    set auto? false! ]2 P0 v7 ?$ S5 x% l
    set green-light-up? true, l4 n2 `! m( a8 Y& a5 C
    set my-row -1: \4 N2 C7 [& \3 o( i/ R; a) n: E* y
    set my-column -1
# k1 |; l1 t" a    set my-phase -1
" m4 o; c1 r2 d0 |$ d    set pcolor brown + 3
( X8 ]. l. v# S" g  ]  J& r9 w! q7 @: F. X. p

& c9 M0 L$ J% _+ J, k  ;; initialize the global variables that hold patch agentsets
% {. f( o7 B  [) r: u# D5 @" U  set roads patches with( R4 g& h+ f2 |; }, s
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
' _( T3 Z+ I& Q' q8 r    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
, b/ n' K% y; b! X  set intersections roads with6 O, K# ~% `6 w+ \6 U
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and' L/ {. M1 p3 e
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
/ c4 _& Q5 e( ]9 r1 x
8 r7 r% j* i& r3 ~) Y" _  ask roads [ set pcolor white ]8 Z0 _0 O2 V9 J
    setup-intersections- `- F# A& O! K3 l- i: h
end
) z9 L5 g% _6 g' f% c; N/ C其中定义道路的句子,如下所示,是什么意思啊?
- t/ I" w8 C# k: Y& i* v, G: I set roads patches with% b! e5 B9 w0 y
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
$ ?2 T0 O# m8 p2 L* ]    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
* d! e7 y+ C9 @4 _7 @% k9 Y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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