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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。% E/ R  G0 I6 {% [" u9 ?* m
netlogo自带的social science--traffic grid这一例子当中,
9 A: X7 m! }5 K3 |. ~/ Eglobals: o2 X- g; ^# |
[
( q; k' V- V+ }  grid-x-inc               ;; the amount of patches in between two roads in the x direction
- U  H& X4 A! @" K  grid-y-inc               ;; the amount of patches in between two roads in the y direction
6 D& }. e9 k: V  a  acceleration             ;; the constant that controls how much a car speeds up or slows down by if: g" T  b1 ]9 a0 g  M& N0 z/ M' S
                           ;; it is to accelerate or decelerate
4 S, b3 A; t) w$ d# f  phase                    ;; keeps track of the phase
& y; f% ]$ w5 e5 F% E+ l6 S# n) m  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
+ o7 U" D8 N3 Q. e% R) a  current-light            ;; the currently selected light
- F1 z. {6 x& U7 o: }0 ]5 [
5 ~2 I0 O/ g- J% k; H  ;; patch agentsets6 b  B) ?& s# _3 T  p
  intersections ;; agentset containing the patches that are intersections
; s8 V* ]: E: v% K$ t& K- y  roads         ;; agentset containing the patches that are roads" U7 I5 z4 u: ~
]+ p4 |# R4 ~* F9 O! n9 F% o! \

+ d8 U8 A) p1 k6 C0 J! x# \0 _5 dturtles-own
& B' u2 u5 j, B+ A" m[
- G/ Q5 C% h! C( ?% O" ~  speed     ;; the speed of the turtle* ^5 ?% o; _: m8 }
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right7 a# v, y! F$ a2 w5 ]4 f, r" h1 o8 K8 n
  wait-time ;; the amount of time since the last time a turtle has moved5 b, [- d; s  s. V6 G+ r$ P8 `
]; |. p+ W/ j  ]3 `) t

' c' f; {& t' @) spatches-own! {$ k+ I: k$ J! R1 I& d; A
[
- F4 }& ?% R- X3 X# H  intersection?   ;; true if the patch is at the intersection of two roads
$ w4 h/ X- D( v4 ?: j+ S  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.; p  x2 {& |& W# R6 O  \
                  ;; false for a non-intersection patches.
" g/ A* o7 Z9 y" w  my-row          ;; the row of the intersection counting from the upper left corner of the
- P; k# H* Y; `4 P0 w7 _                  ;; world.  -1 for non-intersection patches.
- F: J! V* f: a2 O  my-column       ;; the column of the intersection counting from the upper left corner of the
) B" K. j- o/ Y) z- ?4 g/ V8 b                  ;; world.  -1 for non-intersection patches.. t4 r4 F5 T& L- {/ B+ R
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.+ R' ]4 _' i5 ~3 s, z- u1 C( |" u
  auto?           ;; whether or not this intersection will switch automatically.3 M+ Y* k7 R" y7 ]- O( H% v4 w
                  ;; false for non-intersection patches.' W) U: T# [: q. N6 _
]
3 X7 D9 A8 G( e; @
+ w9 ]$ B2 h) k$ x* ]' G2 D
& X' ^; y+ t9 F8 W;;;;;;;;;;;;;;;;;;;;;;
% |0 h3 |& f- _  U0 `. b$ ]; t! K;; Setup Procedures ;;
4 \6 k0 ?9 i/ h- x. J  P3 o0 y" [;;;;;;;;;;;;;;;;;;;;;;
1 m1 a  a- ^" \( i$ ^% I# r) a7 x$ J: B
;; Initialize the display by giving the global and patch variables initial values.
1 x: T- z$ _) f. E;; Create num-cars of turtles if there are enough road patches for one turtle to' \, u! H( T; U5 m
;; be created per road patch. Set up the plots.5 P, m6 T! I6 N3 @" m! u
to setup; s5 Q( x" O- ^1 Q
  ca
2 B/ r  J/ f$ g" m: U9 t$ Z9 B  setup-globals
7 t/ T! g! Q% R! r: ^
) ]5 N9 F! z# y; h) y' m  ;; First we ask the patches to draw themselves and set up a few variables. I* t* y0 `4 d
  setup-patches
  g, X) f/ t% ~6 p- z6 V  make-current one-of intersections
. i; E; e, H$ G2 E  label-current
& B! ?8 l- L  m; d4 n0 h1 ~- n( `8 c/ ?+ s$ N- l2 F$ {
  set-default-shape turtles "car"
9 ~' B. l  t9 N" a$ Y. ^2 F" q; D8 d* u0 g; h# i
  if (num-cars > count roads)3 U. k; {9 Q4 s8 M, M+ M$ @  k
  [" a2 U* x, M  }/ I% }, K- C8 Y2 c
    user-message (word "There are too many cars for the amount of "
0 U: y( \6 w  _( @) m& m                       "road.  Either increase the amount of roads "
, f6 G# y5 T' _; ?8 D  ~                       "by increasing the GRID-SIZE-X or "
, Y) U5 u+ @% Q% r2 q                       "GRID-SIZE-Y sliders, or decrease the "
( f0 r5 g) m) ~  P" u; e2 |) X4 U                       "number of cars by lowering the NUMBER slider.\n"6 T7 ]# i  O) g$ @9 s5 e7 g' B
                       "The setup has stopped.")" U* |' C, d5 M7 L+ G* j
    stop6 w# p3 m4 i8 f/ g
  ]* r& |) a/ W) X- m! l( T( {
: M; C; F0 I7 t0 m$ n
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color) {- a9 q6 A9 F+ _8 }
  crt num-cars0 b, v' O) b1 ^  {/ b' G$ o2 S8 u* @* M
  [
  A& b' c' l( F# h$ J1 \- {! x! K    setup-cars
+ r) g( S& f; G9 |    set-car-color% {  f; f8 a* s$ g) t- i1 a) T
    record-data/ K/ ?- z; U; Y6 A
  ]- i" E9 X: D# _$ M6 i% U
- f! M0 M. m) N+ r; \! o
  ;; give the turtles an initial speed' S# k2 Y: q0 q$ T& t
  ask turtles [ set-car-speed ]
) O- y4 o: I: |, q2 z% H+ c2 p" u$ B" P) j, w
  reset-ticks  G8 Y/ P6 e! [  }  f
end; `: q6 l6 ~$ j* F. j, p

4 `! m7 w% k0 j;; Initialize the global variables to appropriate values
+ Q  a5 a. U* |) \+ P( f1 I2 wto setup-globals
7 a% d. d1 W$ ^  set current-light nobody ;; just for now, since there are no lights yet. O& M5 E% U% b! k1 I
  set phase 0+ [, s* G: k) @8 I! v' s
  set num-cars-stopped 0/ q8 E) L* \7 g; k) K: L( s6 r" T
  set grid-x-inc world-width / grid-size-x8 K6 w( z& O  b5 t- j5 ~& |. z% u
  set grid-y-inc world-height / grid-size-y
2 A$ }6 R( s0 S7 P8 y3 ]4 }$ M+ o4 Y( v# w/ V
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
6 V, _: T# b: l  X2 N7 @  set acceleration 0.099
6 P7 m& i/ w& T$ U. m2 yend% w! u  d1 z$ @) W" V" s% l7 \& Z

' t7 E0 q- S& [" g;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
8 a0 z: G. A! U4 V6 x1 X;; and initialize the traffic lights to one setting% x! F: K3 F2 C
to setup-patches) n1 b3 |) C' O1 [8 `  c* z5 a
  ;; initialize the patch-owned variables and color the patches to a base-color
: B$ a1 w, a2 U4 T  ask patches
0 h4 Z. z- n/ L  [8 |1 A5 z/ @, M8 N; u
    set intersection? false" |' k9 k# g3 k; u8 d  d
    set auto? false1 m7 @5 ~  U' v  p( }5 P0 O$ `
    set green-light-up? true% Z( I6 ~9 H+ P, O/ m5 r
    set my-row -14 L0 e6 b  ?# d1 L0 [# ?- @0 r
    set my-column -1: s" `: I- R9 K% s% b. N
    set my-phase -1. e7 T7 u! I) B- a/ I
    set pcolor brown + 3# W1 e4 j6 `0 _0 k$ B9 K2 G" p6 z
  ]) I6 F) a6 J# m$ x/ Y
8 s# y+ M* a$ I( l* l
  ;; initialize the global variables that hold patch agentsets! d. d6 F+ X4 L3 ^. W# s; c
  set roads patches with) t5 o% Y  F8 H  i: t1 X
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or4 x4 M/ A& C) a! K! V$ }2 n
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]7 F& V! Y5 U, e  f1 i4 U3 ?) M+ [2 M8 y. _
  set intersections roads with
# q( ?; P4 r' L% X. D    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and5 R% p2 D/ K. Q; a7 z# M
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
2 m. o, u0 b- D+ |6 R% `8 w2 q& l3 z
  ask roads [ set pcolor white ]6 W8 v7 _* T6 [/ d4 _
    setup-intersections* m1 ]- ^5 g( E( l8 {. A$ M# m
end
' j  p/ {; V9 ~其中定义道路的句子,如下所示,是什么意思啊?
5 C  a0 T% l( n. X set roads patches with: p! E4 W( Q/ P6 [
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or& {( V" [- H. {' f
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]" c: U( I2 `2 u' l
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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