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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。  {( c# i; J; O0 `& j
netlogo自带的social science--traffic grid这一例子当中,
2 n( c& i! E4 d/ ~, c% M) Gglobals) ~  [: b" v. H) O4 t! S: ~
[4 O$ m+ @; b; w8 S8 i( f5 I
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
" w1 y2 i# O, r/ O* B  grid-y-inc               ;; the amount of patches in between two roads in the y direction, |' P7 O) `( o% m' \
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if& i$ {+ c5 u8 q6 C  x7 I9 S
                           ;; it is to accelerate or decelerate1 M9 V* i9 F3 S9 ^% i1 l: ?, t. u. ?
  phase                    ;; keeps track of the phase2 F; T2 }3 f$ V' y! L6 M9 h
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure6 v' V3 Q1 E1 |( H+ F2 |' ~
  current-light            ;; the currently selected light
9 K" E4 `: W+ T  l- |, P2 k& h% S
; d5 }6 E2 x/ c* L7 k; F  ;; patch agentsets
( d, ?$ J; `+ a6 e- l. r  intersections ;; agentset containing the patches that are intersections6 U! K7 V1 f# b
  roads         ;; agentset containing the patches that are roads
6 i9 }- ]8 ^" P1 D]0 y+ r$ T8 P" C' q- u3 e9 o

) }1 Y  @9 V) p0 d5 |turtles-own& c( p  ^; P* g: U
[0 v" b; j) [5 N- X6 h
  speed     ;; the speed of the turtle
  Q0 M% {7 E& Q& z# l- _. ?  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
$ i# R& }( ?3 R" D) x" X4 o: z  wait-time ;; the amount of time since the last time a turtle has moved& j5 r6 Y4 d* l- O7 J' K3 l
]
+ f4 T2 a5 ~) z8 v( W3 V6 R* i% D$ `' z1 L) m' K
patches-own# W, s, R: v( V0 c- I1 [* O( O8 _+ `
[$ f( _! a+ i& c# S. [: H
  intersection?   ;; true if the patch is at the intersection of two roads" p: {' B: Q# m& d& N! X! Y
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
$ t4 O& d! k9 L                  ;; false for a non-intersection patches.2 r3 h' q2 N# {# a3 ~
  my-row          ;; the row of the intersection counting from the upper left corner of the
" |1 L' q2 q; n/ B# ]                  ;; world.  -1 for non-intersection patches.; I  o8 w% Z& _* H
  my-column       ;; the column of the intersection counting from the upper left corner of the  W8 L8 O8 E. `0 g
                  ;; world.  -1 for non-intersection patches.
" Y# Z' X( Q) W3 v1 J  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.) h# O  Q* o' u' |1 W; E
  auto?           ;; whether or not this intersection will switch automatically.4 ]; r  [- A2 X
                  ;; false for non-intersection patches.  b$ A% Q. `- x( C9 v
]" f: Q. |3 i5 r( O* @
1 u! h. t6 D7 @5 a( p! ~7 \

4 D1 n$ V# T. N* G  R;;;;;;;;;;;;;;;;;;;;;;/ ~. I: U6 e  F* F  v9 v2 L3 Z. s4 N/ l
;; Setup Procedures ;;' [6 _) R  X" E
;;;;;;;;;;;;;;;;;;;;;;, k1 H* G9 e( |
. F; K6 [+ N% U* C. [
;; Initialize the display by giving the global and patch variables initial values.
; s# R' h& {3 G  p* O;; Create num-cars of turtles if there are enough road patches for one turtle to
# A  H4 \! z2 s8 _& p& C;; be created per road patch. Set up the plots.
( E0 q% [, u1 [$ b3 n" X! {. ]to setup: t8 Y$ H& B  t' b" T* M
  ca
$ o" B, p. `9 v2 V( d  setup-globals
0 E" p$ t) N3 r" c
0 q$ Z; J1 m$ z* l, t  ;; First we ask the patches to draw themselves and set up a few variables
7 m' I# {$ C8 B# X6 i  setup-patches
* h! H0 |8 @; T' I2 \2 E  make-current one-of intersections0 b8 u2 G8 v  {
  label-current
$ s) O  J7 g+ w( M% w5 F) J
, h6 e2 N2 t& y  ~' b8 z  set-default-shape turtles "car"
) K" x, A4 y: e4 A! o) y+ A" G+ L( p$ J# r: [) c; E
  if (num-cars > count roads)
, V- a8 C% d" G' r& K1 _8 a  [
( n& ]3 `, ?- P$ |1 ~9 X) L    user-message (word "There are too many cars for the amount of "
! S+ J" D& E/ v0 E                       "road.  Either increase the amount of roads "
: X3 @$ N' U" A+ _, Q' H                       "by increasing the GRID-SIZE-X or "
/ ^$ I1 B8 Z! s' V                       "GRID-SIZE-Y sliders, or decrease the "
) M" ~9 n- G" D' ^- O3 f                       "number of cars by lowering the NUMBER slider.\n"$ D: E# Q# P) H% d
                       "The setup has stopped.")
3 H/ ]& x; R. p- l6 n    stop
6 t. J% @7 \9 L; V* w  J0 E8 [  ]
; T/ N/ F) g. Q1 L' N0 Y6 v5 `% f$ c
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color' K5 h8 c* k2 p' W( l- S
  crt num-cars2 ^& M2 y5 f- E$ W# q* L% V
  [
9 r) I8 D7 F1 g& J8 @7 p    setup-cars4 m- e6 K' f# v2 W
    set-car-color. }( W& [$ a+ t- w! h8 o
    record-data
. l0 B9 p( O  U2 c1 ~  ]( @0 t) k# r6 F* C* q$ c' d
  X; Z. v4 K5 @
  ;; give the turtles an initial speed9 v" p: e5 `) |
  ask turtles [ set-car-speed ]
; y' V/ @+ H0 W$ A3 N; V+ w* ?. U
, ^- L$ M6 V9 m, o" g* t  reset-ticks
. I. q; j* k. i, {end
& q+ a/ S, I5 O& B) i+ D, v# i
! g6 |% z6 h2 W/ g8 Q, r" _;; Initialize the global variables to appropriate values
% j, V. o% d- U0 w( c+ Q1 vto setup-globals9 u9 ~9 P" r- \9 `/ r
  set current-light nobody ;; just for now, since there are no lights yet
% j  T& v& B5 v2 e  set phase 0
9 f& i" S( {) c; u! L( [& w. I  set num-cars-stopped 0
5 d$ q/ ^: h# C6 P  set grid-x-inc world-width / grid-size-x
8 F* s+ w+ t8 z! m5 R  set grid-y-inc world-height / grid-size-y- v+ g+ F% a: j+ _6 G/ g$ p

- Z5 Y4 ~6 E' R/ M  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary6 W' M, b& F2 t5 m$ x
  set acceleration 0.0992 w5 w1 n" r9 K, h  {
end/ S  N6 c" C5 N" D$ P
& M3 n& Y9 X5 C  {4 X# k5 d! g7 @
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
+ v# j7 r; ?# X0 w  M;; and initialize the traffic lights to one setting
  R4 w8 f& i, Jto setup-patches
) r4 V- E2 m8 y6 w& |/ F5 Q  ;; initialize the patch-owned variables and color the patches to a base-color: P( X, t& o+ t9 v: y( `
  ask patches' _2 \/ ^$ v' a0 y0 K$ h4 Z
  [7 p' K0 U9 G" A0 E, W: P- c3 k
    set intersection? false
  D  k4 M) x0 i8 R8 p    set auto? false
5 `; p1 C% b' s& A* ^" k! U    set green-light-up? true
; U' q( U/ ^) c    set my-row -1
7 U1 k8 J; [* u- r    set my-column -1, `* d( c3 |' {2 k  P4 a6 j+ u& _
    set my-phase -1' t" j2 A7 o2 k! @9 G2 R& N$ M# d
    set pcolor brown + 3
1 H% ?% n2 w9 ^8 a6 F& Y! B+ _  ]2 Q2 H. P- I( K! d9 ?

3 X( J8 V. @4 f: d% a  ;; initialize the global variables that hold patch agentsets, c5 C" \1 B! Q" v  |+ s
  set roads patches with
6 H( [0 s  W/ g: N! y    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
1 i6 v0 I6 I/ q* \  \1 f5 T! N2 F    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]+ i. D. w. E+ b  i  \1 d
  set intersections roads with
: }! y- w" S, c  V* \* P    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and' v- E" [2 v& x! `+ E
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]. `% z9 q/ R/ `" o+ V$ i/ X% a+ s

* C- e3 J6 A% L* V6 t& s: L  ask roads [ set pcolor white ]* G$ {4 p/ ]6 r7 O4 T
    setup-intersections
6 W) p& U. @  f0 ]5 K" r& W, Y1 t/ gend
, E# o  ^$ T8 E: s" H其中定义道路的句子,如下所示,是什么意思啊?
% f! p7 |" ~$ i4 P set roads patches with+ e/ m$ ^/ Z+ W: c* U2 y
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or' V8 m. ^8 u3 V
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]* e( W4 z: ]9 a# j, 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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