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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。
) t( X& |3 B6 \$ `6 X  ^! u/ v1 Enetlogo自带的social science--traffic grid这一例子当中,
( a' K7 i* W3 f# n0 A( eglobals; `3 z" \8 s6 K8 ~1 x' p2 F, E
[9 n0 X8 |0 U2 B4 o1 Q# x
  grid-x-inc               ;; the amount of patches in between two roads in the x direction9 L1 m$ I) l: V. g4 n/ g- h! R
  grid-y-inc               ;; the amount of patches in between two roads in the y direction
/ G1 S1 d2 A- V* f% s  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
5 G" c0 S; D+ H7 F. M4 H% |8 g                           ;; it is to accelerate or decelerate
6 A; [0 v& }% z( e9 n  phase                    ;; keeps track of the phase
/ Z3 t: N$ s& x: C5 A  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
& m; Q( q" N  ^1 B: S/ h8 X  current-light            ;; the currently selected light
+ ?- a* y8 K' |6 ^/ p6 |
* `& I, A, v+ e# `) A  ;; patch agentsets
. S4 \! y; M; d% C8 `  intersections ;; agentset containing the patches that are intersections
. h; r/ U! n  I) ?9 S$ L( w7 H  roads         ;; agentset containing the patches that are roads
/ s( N- J7 i7 R]) Z! W$ |/ V. S; b

9 W1 z- M9 c% k' ~turtles-own
$ v. }7 q# N! @$ w, C- [5 T7 o1 p[
$ j& K0 t: F  ?8 e/ Y& @  speed     ;; the speed of the turtle
( U, J% S1 f2 n& I1 R  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
$ A+ V, z+ }4 T5 F  wait-time ;; the amount of time since the last time a turtle has moved6 `, n- [$ `, n$ m' X0 w
]
$ O7 o$ n( U/ S8 `. Z# d1 g$ `9 Y/ q9 y/ N
patches-own
! S1 t4 T- q) X0 Z4 z9 p% I[
, f$ Z: I0 u/ }  intersection?   ;; true if the patch is at the intersection of two roads
: [3 Q& P5 W9 Q  y; A% F  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.9 z9 p5 m0 r* w, A1 \
                  ;; false for a non-intersection patches.8 g9 v' q- F; y) k0 N
  my-row          ;; the row of the intersection counting from the upper left corner of the
0 h! w0 w; n" }9 ?8 D                  ;; world.  -1 for non-intersection patches.
  [! |. i" R5 O. ]  my-column       ;; the column of the intersection counting from the upper left corner of the
6 ]3 F# n" L  z1 R2 {6 H6 N/ l$ j7 I                  ;; world.  -1 for non-intersection patches.8 e8 X+ o) g3 q9 M1 s4 y2 t2 ?, p
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
& \+ w7 p2 v% P0 ^7 {  auto?           ;; whether or not this intersection will switch automatically.
6 b, Z# J% R; r. Z; o                  ;; false for non-intersection patches.' p' z) ?  l6 Q
]
" ?( L) }: @" s6 Y5 U; r
8 w2 Y% a/ W' l3 a1 Q3 G+ q: k5 E% C; |- `+ @
;;;;;;;;;;;;;;;;;;;;;;
" N  [' h: I! r* O7 n$ ?# d0 J& m;; Setup Procedures ;;
, n0 I: m" y' _7 W3 n;;;;;;;;;;;;;;;;;;;;;;. `9 \( k! o5 G+ ~  t

  s$ C. i# n5 ~$ T6 I" h: y% u;; Initialize the display by giving the global and patch variables initial values.2 G- v. E9 M5 `6 y' v3 f' T
;; Create num-cars of turtles if there are enough road patches for one turtle to1 m# @; _! l( I  P2 a
;; be created per road patch. Set up the plots.8 d0 g# h  q5 o; l  U4 [
to setup
! t3 n. p" V1 Y7 R9 ~5 b  ca
: J0 d8 c* r0 V: z+ l  T9 p" L  setup-globals0 O3 g( v5 _2 w  \# B* p; j
, u( _: X2 D# d% ]1 P
  ;; First we ask the patches to draw themselves and set up a few variables
- z  d6 S2 ~6 O; q9 q/ G6 F  setup-patches, M. E2 {% x2 [3 J) {' A
  make-current one-of intersections
/ ^2 c- m9 {' I  label-current
' U# U! c" e( E8 p  k
1 n; K# {! o* J7 K! G: h2 r# R" N  set-default-shape turtles "car"6 w: v6 u/ }; _7 i& w

' _' ^4 h( r. D5 E" s  if (num-cars > count roads)9 H9 r. G+ V! r$ R8 V- t, s! U
  [
6 A2 w; |, y" |9 N2 M/ O" a    user-message (word "There are too many cars for the amount of "
! S4 c2 F5 H0 N0 u                       "road.  Either increase the amount of roads "
( b- e% ~/ v# R" c) ^; o                       "by increasing the GRID-SIZE-X or "( V) h' N7 T$ I% _4 O. i
                       "GRID-SIZE-Y sliders, or decrease the ". `! r& F* S* t, S$ V3 C
                       "number of cars by lowering the NUMBER slider.\n"
) i0 m; a) `/ r3 x% A2 B2 `; L& }# D- e4 R                       "The setup has stopped.")
. _, E9 U  q' [$ {    stop
% V$ R& s9 N; @6 G  ]
' \8 L1 v" A9 n  ^0 u" K( N: P
  ?* n& i+ B0 S  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color/ B% ?* K$ x) E0 h7 b1 A* n
  crt num-cars
% X: Y& d  E- i  h/ `& B  [
' U  e  R8 t; i: j* D    setup-cars- `3 s: M& E1 Z8 R: R' b
    set-car-color5 Z* A7 Q0 q/ f0 J2 d5 D+ J
    record-data$ b+ V# C4 }. U2 k  ?6 |0 d8 ^9 |
  ]
) {$ d, T, |5 R
* R- {# w) |( S- g  ;; give the turtles an initial speed
" B9 V  q0 y) {3 i& }3 E! G  ask turtles [ set-car-speed ]
' j1 h0 c: S! q5 p" g/ s
( ]) }; \# b2 |5 A- V  reset-ticks$ P; q; W9 T7 ?$ S' o
end
% _) D% Q& P5 H( k6 J. i! J+ @
% ^) V8 T; _4 @) Q;; Initialize the global variables to appropriate values
% G1 O: `+ a7 a3 ^' O3 Y9 Tto setup-globals
. P" b7 a" K. z2 E  set current-light nobody ;; just for now, since there are no lights yet" N6 }8 z# f! F: x6 q6 Q& C* \
  set phase 0: y, B3 B, S& k- A
  set num-cars-stopped 0
2 B/ M" G! q8 |0 k+ n9 u4 z  set grid-x-inc world-width / grid-size-x
1 @4 D" |! U8 Z: B% J" Y% i  set grid-y-inc world-height / grid-size-y  n7 n- ~; w4 c

# w+ @, x% a$ M% g  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary! X' o  \. C5 T, `
  set acceleration 0.099
  s+ J; A5 i6 L8 V( _; Wend
# i$ ]. |! t( |  h8 B# l' _
& o# e# U8 J- J) [  };; Make the patches have appropriate colors, set up the roads and intersections agentsets,7 O" ~- A. ]: F' p
;; and initialize the traffic lights to one setting/ G% H" q+ n% v6 X+ P
to setup-patches1 C, G4 r  Y& w! V$ n& l& B7 z
  ;; initialize the patch-owned variables and color the patches to a base-color. d8 U, Y! I0 t2 d+ P. V, R+ p1 j
  ask patches
# m/ X/ _  k. t, k) H0 o  [  V# h, p: X, n4 G3 @# G6 D
    set intersection? false! e  Q# J! [$ }: G5 x9 ~1 i
    set auto? false
& D! q1 A8 P& l! G0 k9 s' @2 v/ {    set green-light-up? true
5 @; L7 z$ j" l" ~% U& V9 b    set my-row -1& ]4 {( X7 t& t, y+ o& G
    set my-column -1
# J7 w, k( i7 ~! i+ k% N    set my-phase -16 k& [$ `/ x6 Z) x5 _! P
    set pcolor brown + 31 u8 F" b3 E+ A' d: H; x7 r
  ]
- i5 X' y) |) t$ K& h1 U* L1 J# i: I8 \  w+ r6 P
  ;; initialize the global variables that hold patch agentsets
1 a9 @8 H/ J. ^2 ~" O. w. {  set roads patches with& G' {7 x5 n1 P+ h
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
5 Q$ u; a& ]9 n4 {2 j/ C    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
; r2 I8 Y& H' P) C, m  set intersections roads with
! R+ N9 U; E1 m' S& Q    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and. ^$ y1 i$ s+ O; g: z
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]- w6 a+ V; _5 B1 n3 Q) ~2 C7 Z

- `6 [- Z& b5 _7 y) b$ M/ Q  ask roads [ set pcolor white ]5 `# \, N$ d6 l1 J% @) M5 D6 |9 |
    setup-intersections9 X" U! r3 _+ n, D- u
end5 k3 k! R* i& X- {$ v9 v. d3 T
其中定义道路的句子,如下所示,是什么意思啊?1 `2 P5 H4 c' S! M0 Q6 z, T4 E% `
set roads patches with+ @5 S$ w$ H2 N( j; f1 h. t9 G2 t
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or( h6 ~0 X) ^+ M6 m
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]7 X. ]5 n6 J) \8 Z  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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