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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。
5 w( |6 t; G! J8 V3 mnetlogo自带的social science--traffic grid这一例子当中,
! _9 W6 w( k' ]' P" s& ]1 _2 h/ c) Uglobals
6 z5 m! T3 z- Z$ Z& y3 }& b- m[
; S$ T6 V- W! ]2 o* c$ B' j  grid-x-inc               ;; the amount of patches in between two roads in the x direction
' j& `" y" `" w: u  grid-y-inc               ;; the amount of patches in between two roads in the y direction  S+ Q0 o  I6 ~9 F9 ?0 \) [
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
; l6 l: P7 _) d: L, u* _8 e" P                           ;; it is to accelerate or decelerate9 U7 \, `: A7 o
  phase                    ;; keeps track of the phase
1 t$ ?( j0 `& d( o  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
4 @: m& g+ L3 O% t* ^  current-light            ;; the currently selected light
; m9 l$ D9 {6 B+ g1 j) D7 u$ ?5 y( Z, n% l! g2 x. e9 a8 w
  ;; patch agentsets
" o/ S9 x  y& T& p/ T" ^. K8 ^7 ?  intersections ;; agentset containing the patches that are intersections
6 N4 \2 }$ Y- n9 |  roads         ;; agentset containing the patches that are roads
& P- l! m9 \3 ^* Q3 R4 W]& w! ~' T3 w2 g

3 F9 a  X/ C/ ^8 @# r" A8 Cturtles-own' B& Y- t+ N. x1 Z7 m
[
( V$ N1 o- y7 T! z5 |: w& e7 _  speed     ;; the speed of the turtle$ ~+ ~7 E4 X8 t- i2 j+ Z6 n
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
9 {$ ~# c! B9 r! |  wait-time ;; the amount of time since the last time a turtle has moved3 i+ e' r$ e2 N9 R
]
! p" D0 t+ p1 z6 k- L* m( U, U8 o  G) q! F, y& X( a
patches-own" w! ?9 Y9 Q3 S% h5 c
[
# P6 I3 Q) |% B$ E  h& n) A  intersection?   ;; true if the patch is at the intersection of two roads
  {! _  {5 X5 |# x8 c0 o* v  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
8 }0 \( G# t( t# c1 y                  ;; false for a non-intersection patches.& m5 U! k' _3 W# F# V3 F1 U3 B
  my-row          ;; the row of the intersection counting from the upper left corner of the
; c3 w/ t6 H' T$ |. ]' i7 r                  ;; world.  -1 for non-intersection patches.
3 m: F+ o$ r# D4 o2 E: n2 c  my-column       ;; the column of the intersection counting from the upper left corner of the
; l. J: d, d2 N                  ;; world.  -1 for non-intersection patches.* M3 o: ^: m1 `4 z: ~' s
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.6 W' p. h0 y8 R' G5 U
  auto?           ;; whether or not this intersection will switch automatically.
; B  O0 B* O' i+ B                  ;; false for non-intersection patches./ s7 l* ~: A0 G( B! L
]' O8 |% ]( }1 V9 k- M+ U( `9 t
8 m# p2 P; m/ C8 U

, o6 `1 D0 V) @;;;;;;;;;;;;;;;;;;;;;;
, D8 e7 t, @( t;; Setup Procedures ;;
0 A- B1 ~5 i9 S3 M6 e;;;;;;;;;;;;;;;;;;;;;;
6 L7 O% e7 P! Z- E" r: C5 x, m( L! p0 U) Y7 h
;; Initialize the display by giving the global and patch variables initial values.
# ?8 P- z2 R5 R) {/ N8 Q1 a9 b;; Create num-cars of turtles if there are enough road patches for one turtle to
: Q; w) A; {9 m3 A; ];; be created per road patch. Set up the plots.
8 ]: S! h0 J6 Z% Fto setup
% t1 v. B. T5 C  ca
. L' F$ u% z$ k4 N  setup-globals
4 M" o- r' ^- m' d: e5 c$ `; `. b! D; i, U
  ;; First we ask the patches to draw themselves and set up a few variables
, o9 V$ F4 Y8 \* z; k  setup-patches
5 Y9 n8 }5 m4 P) `  make-current one-of intersections
- a" N; E. v8 k0 \  label-current; i, b+ G8 ]% s& j4 |

7 \3 [# w) v; D: L* ^! g. A  set-default-shape turtles "car"
- k" E# K# }) O7 i  R. u% |: N, |! I
  if (num-cars > count roads)
$ J( ^! p/ q7 f% m  [
$ {6 }9 t. W9 ^0 F  w& L    user-message (word "There are too many cars for the amount of "6 e' q+ i. o5 w/ Z/ j" H
                       "road.  Either increase the amount of roads "
- v5 m1 ^2 k3 ?! T                       "by increasing the GRID-SIZE-X or "
4 y- X8 }: y2 n2 d. i, R* C, _                       "GRID-SIZE-Y sliders, or decrease the "
7 A5 s* H' T. Q( T# B6 t                       "number of cars by lowering the NUMBER slider.\n"
, X' m1 e! B( T                       "The setup has stopped.")9 @7 e4 g8 n( }: r) Y( M
    stop
" M, |- w7 S" Y1 u- o! t4 j  ]
$ X: _- L& \$ |2 }5 x! ^2 q) j, P  P) W& N3 @
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color  v/ o; c7 H3 H
  crt num-cars. A3 P% k* R* M1 q
  [5 r' b+ }; K1 a+ F: j+ Y
    setup-cars
) t  J/ x2 h1 n    set-car-color# h1 x# S( w  d9 y& K2 D6 o, z/ W
    record-data& j8 S2 e% s- U6 s2 w# R
  ]% p( v, p& Q5 _- J; P! F4 E
0 R7 _& p1 \% b2 Y2 \* l3 y4 q$ ^
  ;; give the turtles an initial speed4 C! ~7 H: V7 b0 q) y+ y* y
  ask turtles [ set-car-speed ]6 I9 ?/ J/ |- K" h/ ~  L7 G* V

5 T- |! q5 u5 w$ H& B  {" \* G3 i; C  reset-ticks8 A* e, C/ _2 d- \/ i
end
: ]/ _0 b, P0 P) t& R
* s0 D) X% ~/ ?9 Y* K$ a;; Initialize the global variables to appropriate values; b5 Z! l) G  z& j0 l
to setup-globals! S* k8 v  L6 ^! E
  set current-light nobody ;; just for now, since there are no lights yet
/ Q, |* V! J3 f4 e0 i  set phase 07 ~# q; r7 p( p4 u' V, Y7 n7 s; }4 g; R
  set num-cars-stopped 0$ N5 V& r% p* ~+ |
  set grid-x-inc world-width / grid-size-x- p0 B% A, u- n) p: I3 ~* F0 r
  set grid-y-inc world-height / grid-size-y
  D- g9 o% [3 {8 r1 X/ e' q7 R. ?$ [, L* A. P" i
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
2 h. E6 J( ^4 R  O+ i  set acceleration 0.099
" L* L3 H* h. L( ?" k# ]end7 J4 a, B# O6 L% `  b

. M! x  B6 [- r1 V;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
5 m# O1 E$ I4 \* z, j$ H;; and initialize the traffic lights to one setting) Q; `. v4 E7 D+ R8 F
to setup-patches7 q0 P% y! x7 k$ {
  ;; initialize the patch-owned variables and color the patches to a base-color) c, O7 t( g. f) `5 V
  ask patches8 Z/ h: y! A! T& k+ [& L- z
  [4 k+ Z9 Q0 e+ X/ j1 ~
    set intersection? false
' l" ?. O& R, H1 S& Y    set auto? false. W$ o! B0 E7 }) w5 z
    set green-light-up? true* o1 p3 n( q/ x3 u
    set my-row -1" y! A* @- C" W9 f
    set my-column -1
0 n3 g3 l0 \9 t  Z0 U3 {% f    set my-phase -1
3 K3 e: O' t$ j/ N8 o. ?. @4 W    set pcolor brown + 3* ~6 H3 o" M# T
  ]8 o. a/ Z, j2 j. E6 u" \
- I2 S5 a" k' y" H! Z( X1 r
  ;; initialize the global variables that hold patch agentsets
# K$ Y6 X* a& b  set roads patches with. J% ^, g9 y- ]5 q
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or1 S1 x' G" z( P0 R! r5 J+ l
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
- s$ d. I4 r0 ?; M/ w  set intersections roads with/ k6 a; f( N: L' j0 M
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and" n* j! |9 c% A: [0 P
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]$ n0 P+ i' Y$ q7 c4 ?

4 O2 E* ^# s- ?, p: @  v  ask roads [ set pcolor white ], ]8 U% s+ X1 [8 p7 O
    setup-intersections& f5 M: G7 c) ~+ e8 E; a7 M& h
end
% o- S4 ~' u* J4 o  E, [0 K! W其中定义道路的句子,如下所示,是什么意思啊?
( i0 q& L, V5 H$ D set roads patches with
9 t# T% D. A% o2 W& h    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or5 s: }. P' C; q! {- H* @0 Y& F
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]4 i" w2 W% j+ h( l5 s5 a- g1 C# t
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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