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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。+ d% u1 T, H8 c  H' l5 S  K5 w
netlogo自带的social science--traffic grid这一例子当中,* J9 l) e7 m& B- g9 _  [" T
globals
# ^& b9 O* P% l! I9 s[
7 F5 K( ^" f' O* F* l1 X9 g  grid-x-inc               ;; the amount of patches in between two roads in the x direction! _6 N: X$ F6 q
  grid-y-inc               ;; the amount of patches in between two roads in the y direction
1 A0 Q5 D! h; U& b) z  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
  V) z+ X" [" S                           ;; it is to accelerate or decelerate
% ~$ T5 V2 [5 m  phase                    ;; keeps track of the phase4 L* p0 B/ w. k) C- i
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
5 S8 N) h5 b1 u  current-light            ;; the currently selected light
; s* C9 A3 ^: A& Q
5 j/ Q- f2 u0 ]# f& Z( v  ;; patch agentsets
) k8 K4 o9 R9 z) {: \3 P" k6 C  intersections ;; agentset containing the patches that are intersections
4 W5 u+ s7 w/ s- G! s  roads         ;; agentset containing the patches that are roads5 ?: J, _6 q2 b% a& k, A: ?
]
3 e- R9 y% I. |, Z: s+ i% V5 t" z1 ?4 n9 j9 R7 C
turtles-own' |9 {$ I: _4 I; T
[
- b3 J/ z  D' T+ f4 _0 o2 ?- d  speed     ;; the speed of the turtle3 I6 k, q) ~9 B+ F1 O/ J: J
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
8 D) P* v  ^; o  y  q  wait-time ;; the amount of time since the last time a turtle has moved
% V9 X2 X1 `* F) @  q1 E9 ?5 Z]
$ c/ {! l9 Z2 n. j' K+ C1 |2 L
6 N! R- f6 f) w% I' v- }0 _patches-own) j$ j( {0 Z7 h
[) o' J) I7 x/ b
  intersection?   ;; true if the patch is at the intersection of two roads; N4 V  z/ J! ?
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
. i) z. V8 k! p3 D, x9 d" ], D                  ;; false for a non-intersection patches.
3 W) d1 ]! d- M) s& M  my-row          ;; the row of the intersection counting from the upper left corner of the: M" N) g) M3 p6 }  E  w
                  ;; world.  -1 for non-intersection patches.
- A9 N& J2 D- Y( F7 D0 f  my-column       ;; the column of the intersection counting from the upper left corner of the, U  {2 M. N5 I9 @# n
                  ;; world.  -1 for non-intersection patches.
: x1 W( F2 S" F! p' I# u* i5 j2 a  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.2 X; w# p7 _' S9 c$ g' f. o; g4 Q; X5 b
  auto?           ;; whether or not this intersection will switch automatically.. z3 \- }, F$ F7 r0 d3 m& L
                  ;; false for non-intersection patches.# ]; _5 n3 d' ~/ q
]9 R8 @; H- j5 y6 A' w: [7 X+ D8 [

4 q/ E& _6 ~9 I: o* ?7 q" X  m2 }. R( P) q! P. l3 ]/ |% q9 a1 ^( k
;;;;;;;;;;;;;;;;;;;;;;; n* u4 K  s: L2 P/ Z# X
;; Setup Procedures ;;, f. U- Z: [- y) T; L7 V
;;;;;;;;;;;;;;;;;;;;;;" w$ H. G& i) E  b* l# P
# c' d5 V8 g1 h) m6 N4 V7 E& A
;; Initialize the display by giving the global and patch variables initial values.
& E* V6 A' a# Y: p5 z; J, F;; Create num-cars of turtles if there are enough road patches for one turtle to( b0 _8 a! X/ {4 A3 ]5 A1 Q3 g
;; be created per road patch. Set up the plots.9 q. @8 }' E0 C8 d  `6 |' V+ G+ w
to setup6 v, t# p4 h/ ^8 b6 B! Y& _
  ca7 h; q% t  J/ N- o/ w3 k; v# B
  setup-globals2 u8 B  }4 \& t0 i
5 t9 i7 A4 {. d1 V% N3 W
  ;; First we ask the patches to draw themselves and set up a few variables" K$ f/ {, f0 k9 C7 f7 w5 [! X
  setup-patches+ l7 W" |# r3 ~7 V+ c
  make-current one-of intersections
! p( |' c; h/ ]' z" w8 S) `  label-current
* h* Z( `/ g, A# {% V: b( M
( i  \$ v* e, o: J0 x* r  set-default-shape turtles "car"( R' W& e( u8 e: O' _
0 k! H8 U# F3 G3 [) [% ]) u
  if (num-cars > count roads)! t* F6 q; K/ ?) D( Z
  [* @7 k+ ^+ u' m0 v5 n
    user-message (word "There are too many cars for the amount of "& ]1 c/ R: _, R, T9 _( N* d! M; @
                       "road.  Either increase the amount of roads "
& Y! {- P8 a4 p+ v                       "by increasing the GRID-SIZE-X or "
1 ]! f7 g# ^6 \6 C% i$ S: L! D. O                       "GRID-SIZE-Y sliders, or decrease the "9 F9 W9 H9 O& ?3 b5 K" ]5 j$ T
                       "number of cars by lowering the NUMBER slider.\n"1 @$ D$ `: q' w5 B5 R: l
                       "The setup has stopped.")
2 L0 g/ R$ a# S) I9 t    stop' K4 ]3 U& V; Q7 s
  ]
1 |$ c8 h" m0 J3 N5 w# P: S, A3 Q& D
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color- k% N7 k  N" r4 M7 U4 ]7 g$ q
  crt num-cars
8 f5 P: a* @# G; F3 ^1 j  [
! O4 a' ~0 F! Q0 t2 J$ D    setup-cars
/ `  I7 n& Q. {! X. j2 b( L    set-car-color  s0 u6 Q" R5 }. p  m( @; C
    record-data1 Y3 t  P& ~/ N$ E2 j% ?( x
  ]
9 f5 x* A, r; d2 E; F1 e$ W7 [! T' U1 s; e! G
  ;; give the turtles an initial speed* {) h  J+ N- s( D# r
  ask turtles [ set-car-speed ]1 v1 p1 Y# {/ T) H& B5 \
* R" h; t) H/ z; E' _' b4 V% S* o
  reset-ticks0 j% t- k7 M6 B/ ]
end
  B' Q+ }) S+ m. e8 K( ]8 U% {% q1 I& l" H  S' C( V
;; Initialize the global variables to appropriate values: ]0 G2 ?) H. l, ]6 p3 R! x
to setup-globals( C% _7 ?3 d5 k8 N" `9 ^
  set current-light nobody ;; just for now, since there are no lights yet
) f3 C% Y1 R: S( _% [: j0 o8 l$ |  set phase 0
. h% U! @1 `, ~% e1 |! W* n) l- l  set num-cars-stopped 05 N% M  n; V( n( e
  set grid-x-inc world-width / grid-size-x
1 `5 F* {! i0 d1 q& S( \  set grid-y-inc world-height / grid-size-y
9 T" {( X0 D9 \) U: N& V: P
2 n8 Z7 \/ k. G" N  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
9 F: s1 k; X5 r  set acceleration 0.099
' U1 \  f7 l# ^; S! d4 kend: q0 C* ?3 K9 P: N

" E9 x: n" s2 R( r; f;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
2 `" W& B, ]9 e% L;; and initialize the traffic lights to one setting" S& n0 @# S6 s5 m
to setup-patches
! u9 p* \- S6 i' a! }  ;; initialize the patch-owned variables and color the patches to a base-color, U# K! t3 l+ m7 Q2 g
  ask patches
# h3 Q, D4 v) `$ g  [" ]4 W5 F; K" H
    set intersection? false+ O6 N( C) B2 N6 z
    set auto? false
: W. j, M' }' c9 x; g2 y    set green-light-up? true6 E$ F  W2 Z5 `- u1 ~
    set my-row -1
0 p! o. f6 h0 o3 s    set my-column -1) R# t3 l- i/ @3 {
    set my-phase -1/ g; x0 ^" b7 e6 C- b- s
    set pcolor brown + 3. |$ L: V* o0 U0 _
  ]
% \# E9 y" A8 s9 G( @' S# i
9 a; v+ E/ t* K% m! {& I  ;; initialize the global variables that hold patch agentsets
9 H; A8 A# y( j! A- W& o( j; t  set roads patches with& K, n" O( N* ^, c6 U) i) }' c
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or: d! z9 T7 R5 ~! E! _% ?
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]! |5 @+ B% S, F
  set intersections roads with% n. Z, r& F8 |! a' }# _
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and+ ^/ p& N, Y; @
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]  _0 F; {7 R8 x" n* E
  f' q4 V2 @2 {! K
  ask roads [ set pcolor white ]/ X* O( ~# @% ?7 {
    setup-intersections# F& ~! o$ r* [# n# b
end
1 @* F0 _# d& m% t8 @其中定义道路的句子,如下所示,是什么意思啊?
+ {5 p# A3 r& r( T4 W set roads patches with
: |' V) ?% R! A    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
) f- e* t7 K) x9 e1 f    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
) s* i5 @$ U$ P6 ~7 p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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