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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。3 k' ^8 d0 g9 K2 K
netlogo自带的social science--traffic grid这一例子当中,
; P+ f  o! h2 s7 j0 oglobals
0 e2 G) i4 d4 I) k0 F/ W0 a$ B[4 D" ^8 S( C7 E5 L5 t
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
* e: u* @" i$ x6 t2 J2 P( [  grid-y-inc               ;; the amount of patches in between two roads in the y direction
) g8 t, V) Y7 `1 c9 R  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
/ f! `5 l- ]$ F+ P8 ~, ~. z                           ;; it is to accelerate or decelerate" u5 j/ Y2 ~5 B- c' [
  phase                    ;; keeps track of the phase% S- m$ u. O* B/ o* G
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure6 o& h$ ~4 }3 s) c& G, r2 u
  current-light            ;; the currently selected light
  ?; ^! M2 C- G0 l) m' i
7 h4 A& C' C) d  ;; patch agentsets
( |7 h9 v0 S  [% h* r+ R  intersections ;; agentset containing the patches that are intersections
/ N; f' V, e# t; N' R- N: `6 Q  roads         ;; agentset containing the patches that are roads3 n; m' {  {" }$ Y
]
. o7 K9 e1 I! \* Y) k
/ g( g+ y* [; s8 Z1 a+ Dturtles-own8 L  w1 D$ S, y: J" U
[0 a. n* O' U# K/ q6 W9 t9 \* p
  speed     ;; the speed of the turtle; M. k$ M  B5 p
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right8 |6 P5 u0 r, x2 D& P0 p
  wait-time ;; the amount of time since the last time a turtle has moved
; p9 g0 P9 v3 h/ _" U% y]
: A  n  d9 D! _- E2 @5 X  O" {3 \8 p1 m: ?' I
patches-own
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$ L! p* `5 h' c. z' }" y# X, ~  intersection?   ;; true if the patch is at the intersection of two roads
. W9 H, B% m) X/ Q$ L  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.2 g5 d& X' J. x  U! X4 w& B
                  ;; false for a non-intersection patches.; g# n. g; N" D  N
  my-row          ;; the row of the intersection counting from the upper left corner of the+ n  _; y6 Q9 }" f# }
                  ;; world.  -1 for non-intersection patches.
. K9 x, z& i& k! d, y5 _  my-column       ;; the column of the intersection counting from the upper left corner of the
: A8 [4 i9 ^) Z- V+ F                  ;; world.  -1 for non-intersection patches.. i6 A/ Z) e5 S8 m
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.: S: e7 _! {( c/ H
  auto?           ;; whether or not this intersection will switch automatically.( P2 j. n. g9 u
                  ;; false for non-intersection patches.
1 p" L4 Z9 ~# s( a9 ^. M]5 `5 s/ N: A% ?8 H

- \* U; k# y. D0 V  g2 ~' W
4 k9 x; H" z8 Y1 r$ |; V+ G# e;;;;;;;;;;;;;;;;;;;;;;
9 x/ K* `& p8 Q& J$ j; p! j$ I* ];; Setup Procedures ;;" k( [  Q& ]/ E% A7 k8 Q! a  y" ]
;;;;;;;;;;;;;;;;;;;;;;
8 W" _' Q3 r$ D. s" |( q! [+ r" K/ r$ M
;; Initialize the display by giving the global and patch variables initial values.
$ O2 I, a: w! u! t" T9 X1 A& A' y: a;; Create num-cars of turtles if there are enough road patches for one turtle to
4 W) Q+ |7 V) O0 a5 E;; be created per road patch. Set up the plots.
  V: {$ V: U  ~! ?( ^" N" M* {" Oto setup8 O2 V; S0 }/ s& {0 G. Q
  ca
$ S2 P! r, ]" q  setup-globals
5 I3 U- d& n2 {# \2 r- ?$ R* Z7 I9 ^) ?3 R" M  [
  ;; First we ask the patches to draw themselves and set up a few variables5 a/ F1 ~& F7 b; s. |& p+ D; d- p
  setup-patches
7 D% M$ @/ U+ k3 N: w1 ~( f5 U; ]  make-current one-of intersections
9 B' m, K3 X3 x1 ^/ W8 G  label-current% g7 \* Y* P; n0 y8 c5 `
/ N( O6 V3 J0 n( u3 B# [  @+ @
  set-default-shape turtles "car"
( h* s: H' J  J5 r5 O4 j7 r) y: n- C# M- s0 k* w+ o' p
  if (num-cars > count roads)2 q6 p4 d6 y, y- y6 d( y
  [. b; {/ }8 b/ Y# v/ q
    user-message (word "There are too many cars for the amount of "
1 J1 D  P7 V9 Y! w, ?                       "road.  Either increase the amount of roads "% Z$ X7 l9 s; V' W% q6 F
                       "by increasing the GRID-SIZE-X or "
3 W  y! X3 w, G+ D# E" L6 i6 W/ \                       "GRID-SIZE-Y sliders, or decrease the "
0 q8 t* X- e8 ~- `- v                       "number of cars by lowering the NUMBER slider.\n"
3 M# q8 n9 Y/ B" U                       "The setup has stopped."). Z0 }, I% s3 G' {" G! k
    stop% K+ @9 V. Z8 C2 a
  ]( b7 V. }& O4 P7 P. u
+ i  B, ~& ~* u( Y
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color/ o$ B6 V" {! J+ R- v: U" |
  crt num-cars1 @0 \& v2 B5 b8 I8 Q
  [
  L" V0 A2 x1 @9 a! u6 ]    setup-cars- P, c2 P' \( l" j( K
    set-car-color
0 m: g! G& o. m. H1 Q3 \    record-data
) T; }, H3 S& E9 s4 ~- O7 v' t  ]
# x9 m6 S) A/ M1 m# H: O7 \. s4 M; \: [7 E
  ;; give the turtles an initial speed$ y1 A6 [& |  Y5 `* V/ l4 U0 o
  ask turtles [ set-car-speed ]
% R: P- Q/ @3 F3 w3 z. X) N; [. s6 i6 y, C
  reset-ticks
( T+ B- I/ H; w; T) Cend2 _) j5 f7 Z& W
1 i" h) b  F- ?0 {# ?/ ]( W1 x# l
;; Initialize the global variables to appropriate values
) R8 X3 }' o  y" P4 r( U! Qto setup-globals
8 l0 W* J! ]% o  set current-light nobody ;; just for now, since there are no lights yet
2 N6 Q' ^7 x+ F( T& f; u- y3 a  set phase 04 b" u& n/ a6 R" j' o6 y% R
  set num-cars-stopped 0) W1 O1 ^# h, r4 s6 H
  set grid-x-inc world-width / grid-size-x
# n0 \9 |7 z" |) L7 {1 e/ e3 |  set grid-y-inc world-height / grid-size-y
" S) u% ~- O8 K% K' b0 r- }8 S8 a/ h  q
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary; b# o9 B- h' C0 f0 }
  set acceleration 0.099; M  K+ f! x9 u
end$ G) J6 _! g/ j2 ?

" P/ r9 ]9 ?/ b" N2 z;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
4 ?) \) X! s# f1 R" K6 ^;; and initialize the traffic lights to one setting
5 Q4 m& t# q/ y) \4 `4 y" C) b+ Eto setup-patches$ L4 `( p2 j% W9 B  }: k
  ;; initialize the patch-owned variables and color the patches to a base-color* q7 t: s& e% M8 J/ G
  ask patches
) N. f: _5 I' g8 V4 s9 {  [; C7 X4 X6 X" s' r" x  L" Z
    set intersection? false
3 @5 _0 J- r( {* c. X    set auto? false, q4 j) I! d; Y% ]
    set green-light-up? true
& e' T; h: S. |- Q; a* v8 f0 n( e    set my-row -12 q: [- B; Z% e
    set my-column -1
# R. u) I1 G% M* g    set my-phase -13 x" S/ i5 H1 z. g3 a( \- G: y% b# ~
    set pcolor brown + 3
0 m0 C# V: d2 R. K  ]6 I5 R4 H& w0 q3 H) S) G; C

& M4 V' \% R8 P* i6 A: [8 N# C  ;; initialize the global variables that hold patch agentsets
4 V+ i6 X- S' `0 p+ W  set roads patches with0 ]% O) _  B6 ~) a
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or; A: R. L$ U' W0 _! j% P& S8 H
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)], H& J6 P, ^7 n  u6 u2 W
  set intersections roads with
! @' }! B' `8 i4 Z% O3 h7 n    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and3 u( e6 Y* v  A% N8 t- `
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
1 e* }( s$ g/ m# |% z: W+ `" V0 j! n; F( s  A+ B* i; I5 p
  ask roads [ set pcolor white ]
1 _8 s. \) k" {" q9 E: r    setup-intersections% S* P( ~7 e* a0 ^  V: r0 k+ P
end
4 u- A- T! t+ u) r# W3 A/ b其中定义道路的句子,如下所示,是什么意思啊?
6 U) C) d* |: y1 g set roads patches with8 ?' r  Z8 g# b
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or# \8 s1 ]  }$ v' f& m, z
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
! i4 ?( n7 M1 ^7 X( Q1 z. ?; l5 O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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