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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。
( y; q: u. G% ~7 S( \; @0 O7 l  enetlogo自带的social science--traffic grid这一例子当中,$ @: r9 U% e9 c5 g- e* d. X: F
globals
6 n# [3 K2 u/ {' g5 n3 a2 B[- P& R/ t2 E# e2 o
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
7 q% S: y1 W/ l3 h7 o2 i" d  grid-y-inc               ;; the amount of patches in between two roads in the y direction1 Q# K- S+ w# {6 r! k
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if; T( M! D2 l: A2 ~6 k7 B2 @: d( s0 }/ J
                           ;; it is to accelerate or decelerate1 |' Q! b% o) d2 J. l
  phase                    ;; keeps track of the phase) W, I) M$ B# c( V: q
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure2 L' t6 Q& `5 f& R) `
  current-light            ;; the currently selected light' B; b5 W* g9 h& c

: s0 e5 b, e6 f3 g  ;; patch agentsets( X; ~# K/ t* @
  intersections ;; agentset containing the patches that are intersections- k: V5 b- c: _$ t
  roads         ;; agentset containing the patches that are roads( w1 I6 R9 d  f
]4 k) ^) J7 j+ K7 H+ l* b

1 ^% E; A9 l, S2 [  s1 l1 t. M7 bturtles-own* G8 }4 z  ?- e4 o$ \
[
' p& g4 q& H2 m$ X+ R' N4 g  speed     ;; the speed of the turtle
" Q! e1 K& `$ ?! R/ c+ l' U  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
1 _2 c, M- |- Y4 I" F  wait-time ;; the amount of time since the last time a turtle has moved
) m1 W1 O: X7 Z* ^2 c7 P]3 E8 L/ v% u( C$ {  Z
/ C5 U* e5 ], d/ p
patches-own
7 i* c  L$ L" e) ~[
! @: `: N; V3 e% W: e  intersection?   ;; true if the patch is at the intersection of two roads
3 C/ }- ~" p% I, ?5 X% l  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.3 l) i5 P" \4 t3 E' Y/ @1 ^
                  ;; false for a non-intersection patches.
0 G! z5 q0 H. l$ p5 Z3 P  my-row          ;; the row of the intersection counting from the upper left corner of the
1 g- T* H6 j: b0 L& Z) B                  ;; world.  -1 for non-intersection patches." }  h9 L5 ~3 [3 [  p3 l! F
  my-column       ;; the column of the intersection counting from the upper left corner of the
7 Z- U; H( S7 v8 I) ^                  ;; world.  -1 for non-intersection patches.* ~) K2 z2 l3 @
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
; }# d0 a3 G$ |4 o9 Q  auto?           ;; whether or not this intersection will switch automatically.
. _) M5 {8 J" s0 o                  ;; false for non-intersection patches.
, R6 ]( A+ m: e$ Q) b]' q0 D! V7 x  c
) h+ [) P+ w8 {1 w. }0 ~, s! E! \
) ^: y! {7 `: Q" o: f
;;;;;;;;;;;;;;;;;;;;;;
# \# M) Z8 P% X7 x/ a& ]5 F;; Setup Procedures ;;
4 m# u7 M0 Y4 i;;;;;;;;;;;;;;;;;;;;;;: H% n3 J8 i2 g5 L9 o2 N% t
/ W2 c' C, y# _" p
;; Initialize the display by giving the global and patch variables initial values.1 U/ V( H  G: Q9 H7 W
;; Create num-cars of turtles if there are enough road patches for one turtle to
2 o3 v8 d& I& h' x# K; g0 k;; be created per road patch. Set up the plots.
# u8 g- J: z8 ]) g/ Rto setup
3 }/ {  _) j# k  ca7 ^  o/ F" A2 H+ M* d
  setup-globals: S. K8 X" |& V' D7 @

0 t  j9 v8 d; |  ;; First we ask the patches to draw themselves and set up a few variables
1 M* x8 W( g6 Q, C9 {  setup-patches+ s  d( ^6 c  I# h
  make-current one-of intersections
- E( d9 L9 w! r7 q  label-current
% X' \& G! J  s) S
1 B  N1 J; \3 K" E. y+ M4 B  set-default-shape turtles "car"
" @2 Q$ _6 b( J* A. O
1 a! d. W, L( J. \+ K  if (num-cars > count roads)
8 Q0 p. G+ ^( Q* n  [0 \# B  M6 N( X+ |/ u
    user-message (word "There are too many cars for the amount of "5 t- b8 |: q) i4 t3 |0 r
                       "road.  Either increase the amount of roads "
5 u2 g% I8 n8 S( ^( ]) E                       "by increasing the GRID-SIZE-X or "
  V: I2 A( d7 {0 ?/ {% e7 I' a                       "GRID-SIZE-Y sliders, or decrease the ") n- s: C! ]: ]: A6 l* }" x
                       "number of cars by lowering the NUMBER slider.\n"8 y4 ^$ y. T0 b/ |! r
                       "The setup has stopped.")
; Z% f& h7 Y& W  ]6 A0 D    stop
+ E1 C' p$ l) M  h) ^  ]: l" D4 M0 s7 X* B! L
1 S5 l- ~7 g$ m* \! X! [
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
" }" w; e0 |! f( W* u1 Z8 X; `  crt num-cars
( d0 Q& ?4 Y$ {* r" U0 r! P: `# d  [
9 R: U6 K' |9 v9 R    setup-cars
9 l6 q( V/ u) B# K" p9 t    set-car-color
& I) E( S: ^2 W( w1 T    record-data! ]/ u2 Q  Y4 s/ @7 D3 }3 ?1 U$ W
  ]* y+ _$ W( _2 L8 n: C+ I
" C" X1 b0 W) i2 g
  ;; give the turtles an initial speed
% t9 [9 W& o0 X0 H1 ?  ask turtles [ set-car-speed ]1 B3 a% I' m& l6 {$ V

4 ~% F$ I( s9 o# b5 r  reset-ticks
3 N' t1 ^5 m2 n6 t# H% J' R" v# fend
+ k: n! r8 H2 |- q3 s! Z$ P9 F% C8 \" k" b- H/ h0 C0 p: P" j
;; Initialize the global variables to appropriate values
2 Q& ]3 H+ `1 k& ito setup-globals
- R: b6 Z" E' t; h" d2 i5 ^# b  set current-light nobody ;; just for now, since there are no lights yet9 p5 {# P6 P! V8 ?1 d' k. t$ H
  set phase 0
; x+ d3 H# E3 t$ m; a; E  set num-cars-stopped 0
' m% x  n! O1 L  set grid-x-inc world-width / grid-size-x
  H$ t0 E3 D% _7 F# r0 i0 o4 W8 D  set grid-y-inc world-height / grid-size-y* q8 V- @; Q3 F: L6 C

* g0 X, H6 n! J% a# {4 V% K  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary+ @8 H) t  p1 T
  set acceleration 0.099. T: L4 H4 J+ E' H6 D# \& e
end
6 y: [. `1 u( i9 D
, B1 G* a9 ]  ~;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
8 n: Z7 v6 _. i6 @;; and initialize the traffic lights to one setting5 \0 C! @% K- I8 f
to setup-patches' r" _$ ]7 m9 ~5 `. `
  ;; initialize the patch-owned variables and color the patches to a base-color: Q& D( T7 |( H, \3 g
  ask patches6 g  _# t& J8 d# \/ j4 `
  [
9 B: U8 {3 b% Z# t  m7 q    set intersection? false
1 x2 k! U: S. O" L  q. I& o5 R1 p( Z    set auto? false/ R9 u) f* F) ?( c3 z; D* ]
    set green-light-up? true, x1 j+ i* [5 Y/ B+ b4 M2 i/ M5 P$ p
    set my-row -1+ X5 N% @# D$ Q9 t( u3 K( x
    set my-column -1
; v5 P; d- x& U1 H7 F3 u    set my-phase -1
1 d% h/ K: h7 J/ |* W$ Y    set pcolor brown + 3
# d) A( m) \* G" \$ J  ]
! o- y3 X* F6 _% _: x+ e0 |' m" z+ s' M7 X! @+ j$ D
  ;; initialize the global variables that hold patch agentsets
. X& c6 g0 u' I8 k" K3 L  set roads patches with
5 C' _, b( K& h! |+ u4 }$ y$ W    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
# J# x9 n* |4 Y7 \    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]6 m" W. |2 Q, _. v: D
  set intersections roads with( u+ h) J/ l8 {( o5 \
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and% D% C& }1 j% B4 S
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
/ |/ l! t, N# j4 j; z
' r2 g' f, K- p/ f0 e" m0 a  ask roads [ set pcolor white ]
0 r+ l, h% {0 f& I( W7 r    setup-intersections3 r+ Q9 Z1 h, {9 G
end
" ]+ U# t  ~& H! |其中定义道路的句子,如下所示,是什么意思啊?) I  g& }- Y2 [: b' z
set roads patches with
! }1 X  i: H! L% |    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or, }" A) i$ i- }, k0 [( f
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
  w$ [- k" v) i; b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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