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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。4 k! A7 _+ z5 \
netlogo自带的social science--traffic grid这一例子当中,) ]" e+ M( m) w- x
globals7 N7 T- E% n$ U9 |
[& {9 N3 K3 O& E3 n" p' |5 Q) K
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
+ d  z& j5 K. a  }* s. G  grid-y-inc               ;; the amount of patches in between two roads in the y direction
( s9 r/ l. h; `4 z6 \3 \& y, X+ Y  acceleration             ;; the constant that controls how much a car speeds up or slows down by if! @- `$ u( L0 O% p! v1 |! L. x/ m
                           ;; it is to accelerate or decelerate
/ ]7 [' \% _2 I" k0 Z  phase                    ;; keeps track of the phase
  O# {. }# w; X. F  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
$ y; ~1 ?2 j/ }" m  current-light            ;; the currently selected light' q/ ]' Z  v0 l3 Y  W

2 E( P& s1 Y4 m# S, N& k! L7 L  ;; patch agentsets0 d9 h$ E; M9 q& I5 ^6 X$ @+ f
  intersections ;; agentset containing the patches that are intersections7 R" S' N( X% ?- `% A* T/ e
  roads         ;; agentset containing the patches that are roads- m9 s. @+ `, H, f
]
/ x% _$ e8 z8 I* D& A
2 U6 \4 Q3 X# n/ T1 Q9 w) u7 T* yturtles-own
4 `6 P: _) E5 W( v& e$ a; _6 S[! e. F& x& }* Z1 M% _( q
  speed     ;; the speed of the turtle
( }+ D' \; {; U  up-car?   ;; true if the turtle moves downwards and false if it moves to the right/ E/ j! r1 I& B2 t( C4 l) N
  wait-time ;; the amount of time since the last time a turtle has moved7 W& t' x( r9 o" f9 ^0 B
]* L! D" X& a7 x" ^! t% l7 }
1 k- V, e, [, a# K% r
patches-own
0 ~/ W! L. r, G! k[
6 S1 G. ]5 ^9 K9 G; Y) q  intersection?   ;; true if the patch is at the intersection of two roads0 l6 l6 ~( s) M
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.( r% r5 u4 E9 ]& `% r" ^
                  ;; false for a non-intersection patches.3 u1 n* P  }- ?5 S/ t/ N
  my-row          ;; the row of the intersection counting from the upper left corner of the) d+ J! n+ b0 `+ H
                  ;; world.  -1 for non-intersection patches.
0 _2 Q9 x5 c& B: ~, W  p/ P  my-column       ;; the column of the intersection counting from the upper left corner of the
& ?  j* ]. G+ U% V5 O" b) H9 f6 T7 S                  ;; world.  -1 for non-intersection patches., U  _% r% R9 Y2 |. w( `
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
: U0 s6 r! D& @" s+ m+ [; h  auto?           ;; whether or not this intersection will switch automatically.
/ d5 E; ]) z3 ^                  ;; false for non-intersection patches.
+ @4 `/ U* r6 I, H5 {5 `) A  []" \& g; F: P( t0 U0 b* g

. \% l" W4 G7 s  K. o; R
) n* x0 M0 V# a/ J8 A;;;;;;;;;;;;;;;;;;;;;;$ F( ^' P8 c# q8 `1 K% T$ a0 q
;; Setup Procedures ;;* |& j  l2 A$ t
;;;;;;;;;;;;;;;;;;;;;;' q  B- }- K' g& t: m* V0 f

; D( F4 D! \/ X& i;; Initialize the display by giving the global and patch variables initial values.; a/ D; p1 |' A( u5 N" r! J- y& T, }
;; Create num-cars of turtles if there are enough road patches for one turtle to
" v' [1 D! h, I- P! a3 S$ A+ m6 A- g  G;; be created per road patch. Set up the plots.) ~  g+ s" `8 v# ^' i/ j* H% S, S
to setup
+ U% G9 G/ b; o% e4 J$ L' A  ca0 L2 P. W- q. i
  setup-globals4 r# U8 m# L( @* B3 g( e

& n% ~8 M9 w- U$ B: u) {3 j5 k  ;; First we ask the patches to draw themselves and set up a few variables+ i2 _7 z2 {- m% k" E8 N
  setup-patches8 \" R6 ?; p+ l0 ]
  make-current one-of intersections
8 W" h+ @8 a/ x; T$ P. v* ?. H  label-current
. ^( f  G& X& g. G3 e
% K* p! C; `0 A6 ?& t, l/ g  set-default-shape turtles "car"
3 h2 e  c9 t7 C4 j/ c$ v6 i0 ?2 N# h( M4 Y2 h2 Q
  if (num-cars > count roads): d# p& h, ^5 g; h% H8 r
  [5 E; I9 V1 p/ w9 X* B
    user-message (word "There are too many cars for the amount of "
2 h+ x$ v: @* ?( I  j7 [                       "road.  Either increase the amount of roads "5 e3 I% R+ F5 K$ a8 T8 W
                       "by increasing the GRID-SIZE-X or "* b" O; t3 O- @! g$ x
                       "GRID-SIZE-Y sliders, or decrease the "1 r0 j! [7 y( ~
                       "number of cars by lowering the NUMBER slider.\n"3 G8 Q1 A1 T! K2 Y' `& U* a8 _
                       "The setup has stopped.")
: S  p1 r% H2 T3 _    stop
; e- ?: x; z. k4 ~  ]/ I4 O( G0 K1 q; o+ s% s/ A& ~6 ~; A

( O  j2 ~: V* ~. [0 b% a% H( }. \; p  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color6 G1 ^) _5 S1 ]; P+ Z5 m( u( Q
  crt num-cars9 E. k7 z4 I# G- |8 @9 J' V
  [5 p) a5 _3 s, l- U$ b& @7 ]0 L0 e
    setup-cars
4 Q4 n$ _& w7 p; L( Z: D, s0 l9 A    set-car-color. ?/ e2 |4 o# i1 C8 n' u) d
    record-data
# c$ o; Y! J0 ?+ A6 K' V6 C  ]
: {6 X! U) @: x* N) p0 T# g! ~6 C
$ h. b- m/ \% y' e  ;; give the turtles an initial speed
: I% {% J; N* U/ E, w0 w: K. m) ?  ask turtles [ set-car-speed ]+ h9 Q# Z: N( Z9 w
- W2 ?; O. F6 J9 K* T9 \5 Z3 l6 L0 u: I
  reset-ticks
; [, o" Y; _# F' V" |# D+ U: Yend- `# k2 n+ O( \# N+ o2 E8 P
7 S" h4 V2 P" C
;; Initialize the global variables to appropriate values
% F9 n2 d" M9 M6 z7 W/ _! fto setup-globals
4 D/ D9 r: d. J2 M+ p8 p9 l0 h1 _1 ~$ a  set current-light nobody ;; just for now, since there are no lights yet7 @6 K1 h! w( K+ L& b8 A0 @7 ?, j
  set phase 09 M! o) ~8 {8 e8 u: U* @7 L
  set num-cars-stopped 0
9 H6 p$ v( a5 `$ ?6 I" O, Y  set grid-x-inc world-width / grid-size-x3 ^$ H6 h. d! u3 a0 p+ z0 _- I8 @
  set grid-y-inc world-height / grid-size-y: D! j( s. ^9 p- c- @8 l+ ?
* r4 L. r' g6 s, a2 x
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
9 s  _+ u+ d( s! x$ }  set acceleration 0.099
5 b5 O* d3 V- Vend# q- }$ T$ n: Z* }7 {' Z  G

% E7 P, B. f. I* z# d+ [; G;; Make the patches have appropriate colors, set up the roads and intersections agentsets,' F/ B6 J0 }# l  E! W
;; and initialize the traffic lights to one setting) Q- D$ r8 S( q
to setup-patches
; W2 a. ^- H% v0 f5 A# p1 L  ;; initialize the patch-owned variables and color the patches to a base-color+ M* d# W* n* I. F
  ask patches
6 A, H; l! x* h8 `! m- `: e  [
7 a( ?! W: X0 [! G8 Y2 l    set intersection? false+ \& K5 p/ |& w& j/ _# `
    set auto? false
8 G. U, {9 O5 \* \" M7 @$ q    set green-light-up? true
& P& |3 `6 ~# ~    set my-row -1/ H* d7 b6 [( s2 F; E' G
    set my-column -15 [8 n% c/ p3 Y8 b4 A9 m* p4 B
    set my-phase -1
4 m' w' f) g& x+ S% ^+ V6 \. f    set pcolor brown + 39 b* k# z: Q9 I6 s  N% E: b
  ]
7 j6 S* h* c9 u1 H2 d6 q/ W  I9 i0 t/ @
  ;; initialize the global variables that hold patch agentsets8 W: x' [) I2 I! q' t% q* n0 Z
  set roads patches with5 B+ F. f) O6 w+ G& x, {
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or* G. d9 k) M# K) d. v
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]9 p) r( }& g: |: f, N" f
  set intersections roads with, {& O$ {2 [/ r' J: C
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
; f7 }2 A. I, p& b    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]: Q% z* h& v" ^
7 W/ B, h0 _" y  s& m+ E
  ask roads [ set pcolor white ]
. b, P7 \/ a7 w- f' w% @    setup-intersections- `) A$ E; L  P- ~$ t! f
end3 v/ g! `$ m7 K
其中定义道路的句子,如下所示,是什么意思啊?
  E. k' D. L* j9 O5 p' T set roads patches with- u0 g& X0 ]! S" R6 @2 [
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
* l7 V; S$ Q) K- I4 E+ a6 H  r    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]/ H% {8 A6 @' s0 z; G
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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