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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。
" o& E; m. f! f& _$ G6 H; A3 ]netlogo自带的social science--traffic grid这一例子当中,
8 [  j2 A8 V" S$ k% I, @globals
& B2 V0 g5 l3 ?3 f[, |' I4 e, p1 k# X  c+ E3 Z% ?
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
- L$ j( C* q/ E6 ]# C7 @& [  grid-y-inc               ;; the amount of patches in between two roads in the y direction
3 m/ H# {' a4 a" H" X  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
' P( Y) M7 ^, i. z' G/ e                           ;; it is to accelerate or decelerate# o. w, ?: s) ~
  phase                    ;; keeps track of the phase
/ A/ L5 M& U, L) W% M  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
$ R! j3 K1 @6 r9 G' M- R  current-light            ;; the currently selected light
; H* j4 c+ @: M0 H" u. M) [3 F' z( e; q3 d  p1 Q& k; b
  ;; patch agentsets
! Q7 T  k: V+ A6 i7 [  intersections ;; agentset containing the patches that are intersections
) m* X0 R. U. g  roads         ;; agentset containing the patches that are roads
- X' T3 f, [. y: K  C- y0 X]9 @! U1 J9 \2 |% H7 G* B$ ?
2 R6 I6 [2 m+ R1 z: G8 K
turtles-own
( n, ?( x8 k7 T, i$ [[6 b0 t3 z! B% m: P6 V' ~- g6 E6 |
  speed     ;; the speed of the turtle
# s9 H: ]; Z" {4 g3 b  P2 S  L  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
: R% ^, v& x' B. [$ @# f& I  wait-time ;; the amount of time since the last time a turtle has moved
) G6 ]/ i/ L- b4 H' M/ J  p]
) B- B- M9 i# H1 I' Q6 z! S8 m2 F
  ~' M7 i+ }7 z* R8 Ypatches-own, v$ `( f. O- V
[
# Q6 @' W2 A; u/ D) ?" S5 U( g" b  intersection?   ;; true if the patch is at the intersection of two roads
2 T7 E  P  b8 S* l  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
, x+ C' w2 k$ Z& ]                  ;; false for a non-intersection patches.
% y: o  g9 D+ u+ U. Z( G- Q, R4 q  my-row          ;; the row of the intersection counting from the upper left corner of the% @" W& I* e. l/ a+ ?8 Z
                  ;; world.  -1 for non-intersection patches.
3 t8 z' ?7 k" k8 _( V  my-column       ;; the column of the intersection counting from the upper left corner of the
! m9 k8 \; e: H4 ]5 E; B                  ;; world.  -1 for non-intersection patches.
/ B/ M3 \4 F7 e" A' `" N  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
9 _5 ^/ g+ g  X1 U4 }  auto?           ;; whether or not this intersection will switch automatically.
8 k' W/ C" ]. ^( m6 o& Q                  ;; false for non-intersection patches.& d9 j2 R# ]# z2 T5 U" F
]. i! w+ l% N* e# K+ ~4 T% Z

! p  M* d1 J  X5 k0 D1 e( R2 C1 `; b% m, W) s7 k. n- R
;;;;;;;;;;;;;;;;;;;;;;6 C- i, M- W' u5 M# z7 I' h3 V
;; Setup Procedures ;;9 ]/ I1 R6 z1 {) P
;;;;;;;;;;;;;;;;;;;;;;( O# D" U5 P/ C) Q) B
( `8 F8 f! X, p/ v' ~% ^
;; Initialize the display by giving the global and patch variables initial values.
' P% x: ^$ g( Y* A;; Create num-cars of turtles if there are enough road patches for one turtle to
  P0 X& O, z7 ?- c+ }$ {;; be created per road patch. Set up the plots.0 d" @0 C4 f, E4 u. u* V5 G
to setup
  }6 q7 W$ s. ]9 H* N  ca) P; M+ L6 ]! {; _* l3 J. A
  setup-globals
; b* H! X& T" S. A9 H$ A+ }$ O: j, y+ Z/ {
  ;; First we ask the patches to draw themselves and set up a few variables
8 ^0 ^" b- W5 {; L) m  setup-patches
5 l* N* [/ r, _9 h; @  make-current one-of intersections
3 z8 J( z$ W( z5 t+ Y& q  label-current
9 X  V3 \) s& p' n4 X  K
. ^& W3 Q+ o( G1 @7 U  set-default-shape turtles "car"
2 `( r  }* F$ M- a" I
; ?8 `( ~' ~3 o' H( }  Z' z5 \  if (num-cars > count roads)2 Y8 |$ v2 V. P  G2 t
  [
! `2 X4 h4 K7 Y2 B9 q3 q+ r# t. V    user-message (word "There are too many cars for the amount of "
  |: _" H, E* `$ @& |                       "road.  Either increase the amount of roads "
. g" B- g' c0 Q- g! Q3 a7 P: I                       "by increasing the GRID-SIZE-X or ". L& r& p  Z' K% K5 n& ~
                       "GRID-SIZE-Y sliders, or decrease the "
- h$ q& M% t  z                       "number of cars by lowering the NUMBER slider.\n"' Y8 U3 Z: K5 {6 J1 O
                       "The setup has stopped.")) @$ }, F8 w/ E/ [
    stop) f4 y, L* Q$ l. ^
  ]
& |/ v6 H% B! M, _! a, f; E2 g/ {% C% n
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
1 g  b9 a0 {" @3 c  crt num-cars
9 U0 U+ b) p2 J- a  [8 @, L% `. u' H4 p1 p
    setup-cars
! F; d( z. X; @5 Q$ a/ E$ O0 a/ q    set-car-color
# G6 `9 P7 Q- h9 H+ _( z+ W6 B    record-data+ g% J  H" J! L5 B" }! U3 g: s: h
  ]2 s: ^# ^, I4 f

  h+ c( b# Y/ S0 G! o" j  e1 ~  ;; give the turtles an initial speed7 b9 }* l: l2 {' w, n! Y8 b4 j
  ask turtles [ set-car-speed ]0 t8 _5 m4 \1 o, [( D2 F3 U) L
' {; N* D) _2 b3 @) ]/ O7 t, _
  reset-ticks0 ]+ ]) x4 L4 A% ~9 {
end
& ~; x) J9 U1 ?: V
2 G# p- M( z) U* ~2 |5 x;; Initialize the global variables to appropriate values3 P3 m+ W3 @# S. S% P
to setup-globals+ |" {9 [2 X/ G$ W
  set current-light nobody ;; just for now, since there are no lights yet
0 ~6 C! z8 P- z# G  set phase 01 ?# v4 w& y. @3 r+ e/ {; A" M% j
  set num-cars-stopped 0
8 u  a) |9 a1 W3 g* n+ q  set grid-x-inc world-width / grid-size-x
3 I5 h0 {( K3 v7 i, f! g  set grid-y-inc world-height / grid-size-y- S% Q/ f7 N# {/ Z" h
/ i% ~- E% Q% ^$ |2 N
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
( y7 Q; n$ r5 N. f  set acceleration 0.099
) e' }& U" I" m( o$ jend
2 {# L' T( q# T4 {  ^/ y
2 T& I4 P7 |+ G" E;; Make the patches have appropriate colors, set up the roads and intersections agentsets,- s) P$ M# a1 H* P( [9 q
;; and initialize the traffic lights to one setting6 D) \1 I: r+ P4 {7 c2 `  V
to setup-patches
! J' `' e7 S- X  ;; initialize the patch-owned variables and color the patches to a base-color& E; L5 n4 c8 H% O# c1 l5 ^
  ask patches
6 P0 x& f6 x. x  [
  j$ G" ]% D+ h' z  m7 m# X    set intersection? false
: J" |  u9 X4 w2 ~" q$ }    set auto? false
- |) K  s9 v% u9 Q0 D1 d" L    set green-light-up? true- l3 ?$ L$ ?2 I( x, u5 u% K0 v
    set my-row -18 h% L1 u2 @# o+ w' B2 v, e' W/ Q
    set my-column -1
& G9 S6 C! B1 q% x5 {3 ?    set my-phase -1) l/ |% H- v& }- [0 h
    set pcolor brown + 3
6 f' m( N, P! V" u$ ~  ]
. V' `3 _& f8 A- G6 P" i: U5 h, u5 f8 ^# Z3 s! A
  ;; initialize the global variables that hold patch agentsets1 d* x  t; g" K" c; u9 A
  set roads patches with4 l2 `8 j9 k. H1 {: L
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or5 l8 ?0 v! W! R- A
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
# ?7 P: ?) p, t9 l  set intersections roads with
( M; P0 C4 u9 V    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
9 q: W- q; w) B# m2 A3 A1 z. H8 n    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
% J7 o3 ]" }6 W8 C: K! d. W) T
9 n7 N) l/ V+ i7 j  ask roads [ set pcolor white ]) R6 ~! H" r- n9 H$ u
    setup-intersections
# q% S1 x8 Q. L& l8 O) e6 C6 \end& f3 A6 A4 a9 ~0 i, m1 g
其中定义道路的句子,如下所示,是什么意思啊?" B) A+ H" x6 m
set roads patches with: J& ~, l+ D0 v1 G) V
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or5 F; R! y& _/ W
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]3 P% K- y- O0 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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