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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。
7 N- ]' a' g5 X) t: Ynetlogo自带的social science--traffic grid这一例子当中,
% l( E+ ~# O/ k$ q' L# Aglobals
6 h/ q9 i, d1 k" n6 G[
7 \- }! e( }( X( Q5 p  grid-x-inc               ;; the amount of patches in between two roads in the x direction
; g5 N' p5 S7 [. x5 h* c) b  grid-y-inc               ;; the amount of patches in between two roads in the y direction
3 U0 x! [  J. C" Q+ W. J6 x4 Q  acceleration             ;; the constant that controls how much a car speeds up or slows down by if4 C3 y# X1 |  w. q6 G
                           ;; it is to accelerate or decelerate3 q; Y2 @8 b+ V, y6 ^( {4 o
  phase                    ;; keeps track of the phase
/ B# I8 @2 m" \3 l5 Q  N$ \  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
5 f$ k: d( `. `/ W  current-light            ;; the currently selected light
$ U+ v8 r( _; t' O: u8 r
8 Z' Y# N- F  l, V2 j) \4 G2 n4 m  ;; patch agentsets
3 P, M' [$ L4 N6 Y6 |3 t0 Q  intersections ;; agentset containing the patches that are intersections' K3 N8 B1 Q! p# h% s6 a1 d
  roads         ;; agentset containing the patches that are roads* {1 O& p" T2 W  _8 u
]
+ r6 g0 ?2 {0 a9 }
" |, m$ @, B! K6 T1 F& Q( c/ sturtles-own
4 N. z3 [# D- ^9 b, h: z[, Y$ R/ y9 I$ @6 D
  speed     ;; the speed of the turtle; {! u' }" B, k+ ]! a
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right  v+ F! Q  Y! m: J0 d
  wait-time ;; the amount of time since the last time a turtle has moved
7 I; B( F' W0 w' ~]
6 x+ \/ ?% l) W. T
0 E: Z! |1 w0 m1 r* Y3 gpatches-own
# I' W' D( x, p3 ~8 G: d$ s5 ~[' E  W$ ~) c! @. Z9 U) e! Q# ^
  intersection?   ;; true if the patch is at the intersection of two roads
9 w2 y% B/ F. z1 c9 V  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.* I. S! L9 ?% l+ j  d4 f8 ?
                  ;; false for a non-intersection patches.
" v' K  M' a2 h5 I& g  my-row          ;; the row of the intersection counting from the upper left corner of the
* t1 e* S# d3 Q0 V% ^                  ;; world.  -1 for non-intersection patches.
! `& \. ?; v2 i% Q; h' M$ R  my-column       ;; the column of the intersection counting from the upper left corner of the; O0 h9 O) _! ~- }8 S& G& D
                  ;; world.  -1 for non-intersection patches.) P0 `6 V/ ?1 F
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.2 }: H6 q: F, D5 H5 n# J' E' Q
  auto?           ;; whether or not this intersection will switch automatically.( H" D" A/ i) o" P/ [1 P4 k
                  ;; false for non-intersection patches.# o' |" {( A6 r- Z
], K' I1 j0 X- S% J# ?
# [3 e. R- Z) j* j1 l* D; `& c

+ D: _5 ?0 o! v2 ]" F;;;;;;;;;;;;;;;;;;;;;;* Z6 t9 A1 i, f* K2 P$ A: q
;; Setup Procedures ;;; L5 ]" ~1 ]( _2 P. k
;;;;;;;;;;;;;;;;;;;;;;/ A" q# y  `. x: B

1 L% ^9 b9 x9 s( c" k;; Initialize the display by giving the global and patch variables initial values.# w8 w4 \, T4 E" K! ]4 q/ \7 v
;; Create num-cars of turtles if there are enough road patches for one turtle to
! Q/ S* O4 Q% c. f;; be created per road patch. Set up the plots.
# s6 J( M8 A! q2 Vto setup2 ~+ z- ~/ X( x5 E: ?' l4 I
  ca
" l" f2 ~8 z3 ^" e  setup-globals
& L: I; t9 R  x
4 a0 l; K, m; }% N6 }. d$ b9 \  ;; First we ask the patches to draw themselves and set up a few variables
# F" f- h9 a. ~/ h# A9 w7 l  setup-patches; q( O4 g" N( z+ Y% [  K  J$ H
  make-current one-of intersections9 w* ?8 q  V# e0 l* Y; q
  label-current
% q) ~' C. o: {( t7 r8 c- I8 z0 Q, V$ J
  set-default-shape turtles "car"- ?) s& x$ T, p3 U

7 {& `9 S; X+ V% o  if (num-cars > count roads)8 N0 g$ g: E* Y$ a* S! f" v
  [
- E4 v0 Z0 t9 D" H* p$ T3 T    user-message (word "There are too many cars for the amount of "
+ j* @$ m1 k8 h  O+ }* k( M                       "road.  Either increase the amount of roads "
# O! w; r- y8 |7 |) y. k+ V                       "by increasing the GRID-SIZE-X or "
! ]2 V0 N, n/ f5 r' F6 }9 ^                       "GRID-SIZE-Y sliders, or decrease the "
4 Y& @) o0 q/ R7 ?1 _! B- V  V                       "number of cars by lowering the NUMBER slider.\n"
! D  U" c) y' q6 ~. Y, P1 R                       "The setup has stopped.")' e, h' Q2 `# R
    stop
0 T# j3 }: J4 L) V  ]
/ H5 X5 v4 u0 O: u& x1 w. ^3 c1 p6 W% T& ^* l2 r4 B  g, w
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
0 o3 S3 M2 i, o+ U% E  crt num-cars5 A; s) ]9 S/ T' K
  [
6 w+ g, c6 \7 i    setup-cars
2 i7 L& u4 b: c( f" g    set-car-color0 ^! b, ~' y2 E% s3 D
    record-data
9 A8 V1 J/ L# Z1 `" L% z/ j+ W6 r  ]
# i" q( R% q0 i+ t$ M  G% r# g2 F, }
  ;; give the turtles an initial speed' N2 i, T4 @6 X
  ask turtles [ set-car-speed ]! Y' G* O% B$ N7 b

0 Y4 _% E" p1 [! p7 {- U  K  reset-ticks7 e! {, r+ O- h1 [0 C$ a+ m) ]
end- w) @2 E/ J) T+ v) p+ R! K
2 I; h! i& u, W1 o" _+ }
;; Initialize the global variables to appropriate values
+ B% W4 N& N+ s) [* u/ R" O5 Ito setup-globals$ n' \- p, U3 K$ R) }
  set current-light nobody ;; just for now, since there are no lights yet
0 q4 C" X7 S, ~  ]! c( n* G/ }  set phase 0: ]" H2 X2 Z) `4 ]0 M) `, a
  set num-cars-stopped 0
7 m; d+ V/ ?+ @5 @! D5 m  set grid-x-inc world-width / grid-size-x
+ V8 ~+ M# s* w! B  set grid-y-inc world-height / grid-size-y' f& d* R5 L* Q! r3 I) [% L! J
% Y8 v* D$ d9 ^
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
- v! p- l# [& [% J# ~1 c  set acceleration 0.099
" J6 ~! i8 @& t7 i$ v! Uend
/ c8 N: j* r3 w* `. d+ ~8 h% K5 A& ?( _# s% o% h1 a# B
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
7 B  X/ S& Y5 f;; and initialize the traffic lights to one setting/ K7 B9 v1 q8 M+ @$ ^( I
to setup-patches3 Q2 y/ X3 M" ^6 k
  ;; initialize the patch-owned variables and color the patches to a base-color% @7 }" o  [9 w8 Q5 z6 H# _
  ask patches% Q2 C0 c9 L6 G9 ~( {" L6 o( M
  [) N# q0 @* o3 \( l% `4 K5 q1 E
    set intersection? false
$ o4 a- }% c% R    set auto? false
' Z; \: j; v! Y0 A9 ]    set green-light-up? true
3 E# V% r( t' m% ^    set my-row -1
# o& B9 q# N& [$ K2 l    set my-column -13 W+ j& \; V  V
    set my-phase -1* m1 ]5 T* d0 Z% \( E! W# J1 O
    set pcolor brown + 3
1 u: f, A6 t; O  ]
) t, I& z1 R4 c. q
5 s* [, p2 l: e9 W  O  ;; initialize the global variables that hold patch agentsets
; p' B6 \* ?# |. b9 Q  set roads patches with
/ O0 Q. g4 D8 K4 C! y7 p1 o( u    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
$ d: O$ ], m$ Y$ C    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
" I; Z0 _- c! d' g1 Z) @  set intersections roads with4 r. e- [0 G+ e3 a7 V1 E9 c
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and  D! O: @0 ]# p+ k% v
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]( ^& V# ?$ C/ ]# I2 }- j  U
6 L/ N$ b& A! k6 w* ?3 O, G5 S9 p6 I8 G
  ask roads [ set pcolor white ]1 e! ]4 B/ c  M* ^/ O
    setup-intersections9 [$ @9 A% D9 j3 c' I/ p6 r
end  A% P+ P( T7 i1 j
其中定义道路的句子,如下所示,是什么意思啊?. A- L4 D' p4 W9 s0 |6 {% G
set roads patches with7 V4 O- a* S9 a' b2 A8 ~7 M5 w
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or# f) e! U7 ], P% L( D
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
* l, n5 F: w' z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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