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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& E) n9 R$ [" znetlogo自带的social science--traffic grid这一例子当中," Z3 A  t% g" Q8 h3 `8 B2 H
globals
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  grid-x-inc               ;; the amount of patches in between two roads in the x direction9 h! K) O9 _* a* E
  grid-y-inc               ;; the amount of patches in between two roads in the y direction2 P' G. u0 M( X3 T- F
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
* z$ j& l1 |8 R( b! a# J1 ~! ~1 A                           ;; it is to accelerate or decelerate, ]7 h% r0 x; W9 ^# g) |
  phase                    ;; keeps track of the phase$ Z2 r( A( e! c+ @$ h7 A+ L# Y
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure! H: {! G6 H- S# M+ u
  current-light            ;; the currently selected light
' f8 d3 C3 o: A3 c7 Y+ ?/ P& t8 h$ h- _9 c) B! X) G7 t& O. U
  ;; patch agentsets
2 J! U: Y: ]* W( ?5 ^  intersections ;; agentset containing the patches that are intersections$ K7 {8 ^" f/ @
  roads         ;; agentset containing the patches that are roads
* c: |2 ~7 A, v  ?8 []7 t  l* z8 S5 s9 j0 N3 P' M. d
2 X8 \% b3 y8 c* g- m8 J
turtles-own
+ X$ p" t1 @; ]0 E[
. z" z+ B/ k) \  speed     ;; the speed of the turtle3 O# ]: ~7 _0 c8 U  `
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
4 u/ p$ k$ X, t  wait-time ;; the amount of time since the last time a turtle has moved
' i1 Y) ^# J! f$ m9 a  t]
3 y: E) o8 c% n; u& I3 d" L
3 Y, X; I7 x, l; \; c& Q& upatches-own
# \9 q; m2 `' {+ C  u1 D! S[
( E. Z% _% ~! R* ~  g! j  intersection?   ;; true if the patch is at the intersection of two roads
9 a- s3 I# \7 I# }* `+ a6 c& C  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
. Q3 ^' L0 ]8 V( F/ I9 q3 m                  ;; false for a non-intersection patches.7 _) S9 `2 C' E
  my-row          ;; the row of the intersection counting from the upper left corner of the
7 c8 r1 P+ }; |- \* T5 Y                  ;; world.  -1 for non-intersection patches.* u$ c1 T" n: E; V- P- C1 o
  my-column       ;; the column of the intersection counting from the upper left corner of the$ f) j5 o' M5 H; s3 `9 T7 j
                  ;; world.  -1 for non-intersection patches.
# {5 X, E$ E+ D: Y/ A  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
5 W9 ?% c" d0 ?& R& U: s& B& K; d  auto?           ;; whether or not this intersection will switch automatically." b7 i* y2 [& `( B) |; m; }5 ~
                  ;; false for non-intersection patches.% |3 m6 E$ e! f- r% Q
]
/ v3 h5 z' A3 b
9 Y6 {8 {' U, U. K3 j$ o1 o  E  Z, f1 q6 W( z; g
;;;;;;;;;;;;;;;;;;;;;;
, B6 {, C: h1 {* ]: Q+ M. y;; Setup Procedures ;;
3 m' r+ g) [9 \;;;;;;;;;;;;;;;;;;;;;;
  r2 o% F4 Y' Z* v! n  T1 E7 D( \
6 }3 g  }8 h6 @# G! x( K;; Initialize the display by giving the global and patch variables initial values.9 C6 I/ V  t$ e
;; Create num-cars of turtles if there are enough road patches for one turtle to
; S2 U( e# {# o4 A. |! f;; be created per road patch. Set up the plots.
# F! `! S7 V9 E( E8 `1 Vto setup# R+ _$ v+ u* S: l. @( K$ `
  ca
: a: s* J( Y! V1 }9 K  setup-globals2 i& Q0 V* w) }3 b" a* o2 o0 m2 s

* @5 G( u1 g$ p! O8 N# p9 ^3 \1 F8 \1 D  ;; First we ask the patches to draw themselves and set up a few variables" J7 F3 D8 L) D/ k) h, V
  setup-patches6 \9 @5 f8 }/ }3 L$ \# X5 s
  make-current one-of intersections
' G1 u9 V$ e+ L% P* i# M) R  label-current, q" d' `) q$ l. |( H! j

1 V9 H2 M6 e, t. d  set-default-shape turtles "car"
, K! z2 D; k8 l* e3 ~7 N0 [, p2 ^9 u4 d$ ^2 ?- w# \7 |
  if (num-cars > count roads)( ^" v4 n7 a* c, d
  [
( }+ H2 F9 c! Z0 X/ `    user-message (word "There are too many cars for the amount of "' W0 w4 H. F5 P, a+ T" B
                       "road.  Either increase the amount of roads "
% ?: x' p# e* e                       "by increasing the GRID-SIZE-X or ", f* d! F1 Q' y1 W2 M( h  t
                       "GRID-SIZE-Y sliders, or decrease the "! }6 z1 W' w6 E1 C/ ]
                       "number of cars by lowering the NUMBER slider.\n"+ r& w# b' y4 j; I) o  d( m
                       "The setup has stopped.")" T- V) k7 \  W8 R3 @+ Z
    stop! j" y0 o$ X4 T" P" Z- T, n. l3 H
  ]* e2 O/ P, k3 }) U# k# ]7 I7 g
( m: p; i. u1 n, {, Z! r# y
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
& f8 S' ~7 Z$ s# D; {4 n  crt num-cars
2 o  l1 D; V1 \2 }3 O. W0 }1 [. L  [9 J' c/ J5 j: b' s6 Y7 K
    setup-cars
$ i% V0 z2 K8 J' c  o    set-car-color# L$ ]9 H* N# L$ K
    record-data
, n+ H7 y) F2 O  ]
4 L; E" U5 C3 z( N2 a( k+ U
) a% i- }; j9 W% C8 f* \  ;; give the turtles an initial speed
& T8 z) n3 Q( p) j, t  ask turtles [ set-car-speed ]1 u' x- m- v) Y6 G

/ H$ O( J# r1 c- P( i! O  reset-ticks8 W" J4 O! h/ J$ l8 t+ Q5 b
end
4 C% T" G  R1 B9 t- B; `5 s( N
0 Z( i2 A7 F7 W  |. p6 T;; Initialize the global variables to appropriate values
2 y: ]9 q3 R/ k- {2 G8 Fto setup-globals8 r. F% A7 H% f  q9 v9 s
  set current-light nobody ;; just for now, since there are no lights yet& x3 h; C5 e9 p$ W
  set phase 01 c# Z0 d0 t0 [8 g
  set num-cars-stopped 0
! Z7 y: k/ b" C/ j% E  ?  set grid-x-inc world-width / grid-size-x
  K+ A% J8 \9 o/ @% `2 x/ Q3 W8 t% ]  set grid-y-inc world-height / grid-size-y
6 |$ \/ W6 P0 R; y5 h9 `5 G
9 b4 A" S) t) A: O% P8 Y8 s7 R  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
* o# A1 E5 D$ g  set acceleration 0.099
/ @+ I+ z0 H  M2 R/ `9 \end" x" j, N1 K+ e

9 e% i2 S7 Q: Y# P' ^  _7 @;; Make the patches have appropriate colors, set up the roads and intersections agentsets,1 \5 L! k7 O, s2 I
;; and initialize the traffic lights to one setting
4 o/ r( ]8 U' o$ ~3 }to setup-patches
: e  L8 A" V5 k; z, t& h  ;; initialize the patch-owned variables and color the patches to a base-color6 }! W. V; C9 O0 D* r. w
  ask patches7 X7 t% W' f( ~! _5 B+ O
  [: J, E. C+ F1 q( J1 o/ a7 Y9 `
    set intersection? false! }& z/ D6 n/ w1 g3 J7 F, S
    set auto? false% A, a0 `) e3 u3 x' @
    set green-light-up? true  Z/ A* |7 g" b2 z$ |+ h0 g: [! i
    set my-row -1  c' v: _& }! N
    set my-column -1- I( p: p7 a$ I  J4 R: P! i3 g* x
    set my-phase -1
( m7 d" {  Q- _/ d    set pcolor brown + 3
* }( K  }5 u% q% l+ w; P* E  ]
" q0 y$ Q: a6 m7 W6 ^6 a; d; n3 ?
+ u3 z- B$ r! M# s  ;; initialize the global variables that hold patch agentsets
# R/ B& T; u2 H5 ?  set roads patches with
" F% I! ?$ ^8 e! k    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
9 s, e6 k4 i# g) g    (floor((pycor + max-pycor) mod grid-y-inc) = 0)], K- W  z0 o4 z; Z. ?3 L
  set intersections roads with! p2 S/ r1 x9 R4 H  \6 m( i  K
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
1 z% j/ m! }" l  D$ z4 _. p" S' u    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]- H$ C0 j$ t, {

2 |5 c8 t; t5 d' D9 w) _4 Z% N  ask roads [ set pcolor white ]- W1 `3 G. ]7 s3 j% p) c9 l
    setup-intersections
- C6 j- V' c5 t" send
+ r/ D/ O) S) U  ?其中定义道路的句子,如下所示,是什么意思啊?
0 R9 s# M7 P$ n8 B" V6 o set roads patches with# G3 G8 M# r/ A2 u! O0 @; L. f
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
9 i* X+ \3 a2 n$ x/ @    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]: D$ R, Z! b4 U
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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