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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。6 R9 z' I8 d* h, @, t
netlogo自带的social science--traffic grid这一例子当中,9 p  x- k" K" L. g0 l8 F+ ?% D' J
globals
4 Q! G% S0 a& T. O, {[
; S/ O/ u+ `% N1 ?  grid-x-inc               ;; the amount of patches in between two roads in the x direction
) @" c+ y$ M. r0 n8 m5 R  grid-y-inc               ;; the amount of patches in between two roads in the y direction
- k( |) v: v) ?# w  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
) x! S7 l" v: C4 @, g  T- t4 o                           ;; it is to accelerate or decelerate
3 V9 U* F# B  z0 ~/ ]1 [  phase                    ;; keeps track of the phase7 w+ C: [, c3 F6 b% T2 T
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure4 W+ D6 }+ t/ y* P. e
  current-light            ;; the currently selected light
4 J, P0 y( g8 V3 d% m% u
" X! m* H3 W  g& h  ;; patch agentsets
$ T, O! h5 T- [) }0 |1 a) G* A  intersections ;; agentset containing the patches that are intersections
, T, e( r+ W7 w; f  roads         ;; agentset containing the patches that are roads
% J3 G! @  x/ W]
) Y2 H% X1 n% e$ ~0 T
+ k. v9 C2 D, t, Kturtles-own, \9 x4 J- ]4 V* |# X
[
/ P6 ]: {/ i. _  speed     ;; the speed of the turtle
& J5 u( F( H& B* b4 K9 l- V2 ]  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
$ }2 P( A) W# P* \  b  wait-time ;; the amount of time since the last time a turtle has moved: F/ L+ J. s3 ^/ N2 n9 A% D
]1 r9 G* J0 I5 j9 d3 o8 u7 d

$ H0 t& @% U- r  Vpatches-own) C: w: e- M3 K+ I* u% W
[
8 V# U/ l& ~& b+ ]( X  intersection?   ;; true if the patch is at the intersection of two roads1 N; q4 y, ^( ]% V
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.  |" X6 S- b# ^/ M6 t
                  ;; false for a non-intersection patches.
" J/ T4 @1 H( [1 F  my-row          ;; the row of the intersection counting from the upper left corner of the
% F- R! O2 o; X) t  l/ m6 \; _                  ;; world.  -1 for non-intersection patches.
6 f( E9 F+ I% x/ F$ l# {  my-column       ;; the column of the intersection counting from the upper left corner of the
: Q9 {8 }6 h. c( l$ u- Q" F5 W                  ;; world.  -1 for non-intersection patches.
8 z3 O0 F/ S' _, R7 b/ P6 r7 z" B4 o  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.- k" y* T8 V7 |6 N: [" p3 K
  auto?           ;; whether or not this intersection will switch automatically.( _! r, x% ~+ X6 U/ [& E
                  ;; false for non-intersection patches.
4 K& [/ F0 V, Y3 M. _7 m, g" a0 r]) U# ^( n. ^3 C

5 c; `$ v2 s* v' p7 p9 i8 O( d4 O: t
;;;;;;;;;;;;;;;;;;;;;;
( _2 f) J* B) K' d;; Setup Procedures ;;
5 l$ Z1 B3 }1 i$ I( V: d, s6 L;;;;;;;;;;;;;;;;;;;;;;8 t  t; t  {+ n4 K" k; ^
$ W0 w* N; U/ J" N. G" a4 R- U
;; Initialize the display by giving the global and patch variables initial values.. @% z9 K4 w: c/ ^# u" C
;; Create num-cars of turtles if there are enough road patches for one turtle to+ Q8 A+ E& o+ o! S% f/ Z/ w2 T4 h
;; be created per road patch. Set up the plots.
$ ?2 C0 M6 J( t% x8 X: H( }* tto setup
# G8 e: J4 o  H* q  ca
: l  m: H+ G9 t" ^5 _" Y6 e  setup-globals
7 B5 _8 |8 R% {/ \- }0 P, N
$ s1 T. e8 u& `6 a  ;; First we ask the patches to draw themselves and set up a few variables2 z# r: a& M% P: ~
  setup-patches
. B; k# o6 l5 h% |  make-current one-of intersections6 J& I! b4 C7 P
  label-current
5 I! S+ D0 ~* F' f/ j: L9 k: T
- u7 i$ d: D- W/ L; T" f# Y1 |  set-default-shape turtles "car"8 g; ~$ q. S" F+ s

" T+ O8 b; D8 X7 r  if (num-cars > count roads)+ f) O" V; G+ h" m2 |+ O
  [6 i0 n0 [( o  ~! n
    user-message (word "There are too many cars for the amount of "
9 h) W& ]( p4 K: q3 O/ I# n2 u. e. o                       "road.  Either increase the amount of roads "
5 {( |- M1 u5 E, y4 p                       "by increasing the GRID-SIZE-X or "
( z3 R: J9 ?; }                       "GRID-SIZE-Y sliders, or decrease the "; k4 j( d2 w0 P( O0 L! r
                       "number of cars by lowering the NUMBER slider.\n"
* _* W. P% p8 E$ y" t+ p; R1 g                       "The setup has stopped.")" ^6 x* m( a$ Z& P- \  [- t1 n
    stop0 u0 j/ F# b+ z
  ]
8 l* o5 x* o4 z4 q/ e' d1 ?: x) _: P/ m
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
3 t. x- _: h2 s# d& V, w  i  crt num-cars: M5 O3 o: Y0 j/ a- P" Q
  [& a+ i" P) a! V( f' l& [
    setup-cars
8 H+ V  J7 p2 y; N, N    set-car-color
& e6 V  b6 K: Q3 W' p6 F5 R    record-data
% t2 e0 n! y! }) v  ]
$ H6 I" R- `& |0 _- f$ [$ n9 h- f: t& z  v8 [. o
  ;; give the turtles an initial speed
( `0 Q/ }. N: n  ask turtles [ set-car-speed ]3 u* E# }% j$ i4 v3 a
4 j. S% _: ^5 R2 H, N2 Z2 B
  reset-ticks7 \! n! i1 q4 S- l! V$ u) p: l
end
# P0 n/ V8 E" D
: B, l: }$ U" `. l- n: B5 ?;; Initialize the global variables to appropriate values8 {8 B1 G% l; @* v' Y( c
to setup-globals
* M6 ~+ F) U. g8 o% j" i  set current-light nobody ;; just for now, since there are no lights yet
0 @+ D4 z9 k" p) P, W; {& A  set phase 0  @; ~5 o7 M, z' p" i/ A
  set num-cars-stopped 08 Q! R; L8 T3 ^3 J8 s
  set grid-x-inc world-width / grid-size-x
7 c' g' }7 u) N; u" B! u$ p! `  set grid-y-inc world-height / grid-size-y
5 h( W/ z+ u! \# a0 }: \
0 i' ]# ^/ y! H; @: e; F4 r  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
8 I, G! A* o+ U/ M5 `4 }  set acceleration 0.099
# d' O9 g+ O7 F3 ^  Zend
! {' ?' I; F  `
# C6 G. C/ t. [6 d1 B/ h;; Make the patches have appropriate colors, set up the roads and intersections agentsets,4 s6 H, b3 n5 S2 w2 C: `: c% A
;; and initialize the traffic lights to one setting
) [# l* q, ^( w, I/ |to setup-patches
7 m7 Y7 t# @; q! k: N* k  ;; initialize the patch-owned variables and color the patches to a base-color
) a9 k1 y& ]# S8 I) n/ X$ b  ask patches2 O9 Z9 X. L5 j  i* U/ F; w( \, ^
  [
) A$ M/ D5 k% E3 I. h    set intersection? false
( e+ R9 E- B  Z; _0 n    set auto? false5 M8 S$ N- f$ Q4 C" m0 O
    set green-light-up? true
: p2 F6 ?, b$ j    set my-row -14 `3 X& P( x' ^; ]3 l6 n+ P' k
    set my-column -1, \5 S- c# G+ A; g
    set my-phase -1  `: U  R: T: |5 {7 @
    set pcolor brown + 3% {& E' [' y: r' o; X
  ]
* X7 l+ ~* {( H0 d
" Q5 q% @+ x6 X/ t3 E  Q  ;; initialize the global variables that hold patch agentsets
- K. K& J3 M; [" `# Z  set roads patches with
' p: R% d' o; I    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
, {& @; j/ t% o4 w" D    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
3 w9 u' L# x* T9 E8 |# s  set intersections roads with2 i$ e0 a7 R2 z/ x) N) X: i$ T
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
# Q. l7 A- [% J. a  ?' I' a* g( ~8 w    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]2 D+ U! U4 P6 Z$ f' w) ~4 }3 s

4 T/ p4 J2 L7 e! e  ask roads [ set pcolor white ]. p0 F) w. M2 @) _0 j
    setup-intersections( i& d- O. \1 @$ r
end
5 G6 L6 }# b- O6 n1 g6 L1 k1 r其中定义道路的句子,如下所示,是什么意思啊?
- R: [, K4 J, V: ^! M set roads patches with) }  g# R2 G' X% T& x
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or9 {5 }  H* N9 ~+ v' K/ r8 Q$ Q, M) |8 `
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]1 p# }: U, l' F$ G+ R* X1 T
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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