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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。
5 M3 V$ d2 i- H4 L6 M. A+ u6 E- Znetlogo自带的social science--traffic grid这一例子当中,* d6 v0 M  z" Q$ r$ z3 a1 [
globals& u8 n8 b/ ]$ P9 R: p  H1 ?% ^
[
% x' b$ g& T' G  grid-x-inc               ;; the amount of patches in between two roads in the x direction
- P# _8 u% R  g/ j! V5 k7 \  grid-y-inc               ;; the amount of patches in between two roads in the y direction
8 Y$ n$ V1 b  z% Y  acceleration             ;; the constant that controls how much a car speeds up or slows down by if# ~+ ?$ F* o2 ^
                           ;; it is to accelerate or decelerate* Y" x# X$ d3 I- k4 h
  phase                    ;; keeps track of the phase
2 l8 M& W0 s) }  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
6 E- }0 v$ a  E7 R4 Z: h  current-light            ;; the currently selected light+ |& b' A* C' k8 J4 p+ A( y
* p7 j. U' z# f% g: d$ }
  ;; patch agentsets
  {- D# ]+ t5 S4 u  intersections ;; agentset containing the patches that are intersections
7 ]( l! o" }5 U0 x( Y( Z7 ~  roads         ;; agentset containing the patches that are roads
1 [, @2 o4 A# I3 D]
  n! n1 f  j# F' m4 W2 d( G! P
* q" A2 ?+ ]3 G- @& rturtles-own1 X% V. |7 x: n( b$ z
[5 h+ @3 k' O) @
  speed     ;; the speed of the turtle4 a+ L3 }) d$ M% y3 m7 u
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right7 T5 Z/ @. h6 {6 c  ~: q! C
  wait-time ;; the amount of time since the last time a turtle has moved
4 z1 \& L) J6 x& i( z]7 V  y1 X3 J. j

. L- [" Y6 \1 k$ @: M  B8 U, Qpatches-own2 i: ^) X: r/ k8 K( h, g  b9 h7 T' _
[
, a( Y5 g6 ?& R0 ^9 u( K  intersection?   ;; true if the patch is at the intersection of two roads
3 d9 E" O3 a6 b3 V  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
& P8 E1 P% G/ i4 X                  ;; false for a non-intersection patches.
6 k: ^8 ]; s6 t3 h+ l4 F" x# T  my-row          ;; the row of the intersection counting from the upper left corner of the
% P: J6 u* o# L+ `% n8 _                  ;; world.  -1 for non-intersection patches.
" p5 l! o$ P/ X% E. O  ]  my-column       ;; the column of the intersection counting from the upper left corner of the
9 }4 k. v7 ^: U) _0 S                  ;; world.  -1 for non-intersection patches.
, z1 k4 ?+ Q9 L8 N. J  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.* F* U% I0 p0 n  r
  auto?           ;; whether or not this intersection will switch automatically.
  e" ?9 F. b. T. Y% ~+ p                  ;; false for non-intersection patches.& s3 P( J6 u/ m7 T
]4 Z( u0 l; o: f. [3 k2 D+ H$ n
$ a+ ~4 G: P  M/ g: c% E

: w& l2 `2 l/ x$ T7 c8 H" T& H;;;;;;;;;;;;;;;;;;;;;;
& C' }! X  D$ t# p' A5 W;; Setup Procedures ;;
/ A+ q) `) ^+ X  }  p;;;;;;;;;;;;;;;;;;;;;;
9 Q0 H/ ]9 M6 v& d* n1 F8 j  a% |7 q$ b5 L2 I
;; Initialize the display by giving the global and patch variables initial values.
, Q( ^0 C8 t1 G$ @; c+ E;; Create num-cars of turtles if there are enough road patches for one turtle to' @6 K$ ^' a) `: J9 g
;; be created per road patch. Set up the plots.
/ y  n! O5 ]) v, U: l8 n& rto setup5 u6 F( Z/ r& K
  ca
1 R$ R" H- |3 Y( u% }% m- e- |/ }  setup-globals
" ?" `+ Y6 f. F6 \
2 O. K" Z  y" D; ^5 R3 @  ;; First we ask the patches to draw themselves and set up a few variables6 a. J, |( }1 A0 ?, e2 ?! O
  setup-patches
1 t3 Y* _' s% u( g# e7 s  make-current one-of intersections5 [( V. V" c! P! `
  label-current
9 m6 g4 ]* z- b
7 C0 ?8 j; |8 `8 t; d, M  set-default-shape turtles "car"
9 _9 r. w. z3 o$ w! j  i
  o8 ~$ \5 l6 A; X, {: A4 F$ ~% Q  if (num-cars > count roads)! w# {9 p9 y) ~7 }& a9 Q& r
  [
8 T& v' x6 ^% H9 e$ b" ]    user-message (word "There are too many cars for the amount of "- z' m! C2 G  B0 d2 m: Y2 x
                       "road.  Either increase the amount of roads "; H" ~5 {- l; h1 a
                       "by increasing the GRID-SIZE-X or "
5 s7 |4 m% I% U$ l                       "GRID-SIZE-Y sliders, or decrease the "; h) w- D; {* z( T! L+ P
                       "number of cars by lowering the NUMBER slider.\n"2 |9 ^) p; p7 ?4 p; ~2 h! P5 A
                       "The setup has stopped.")) [6 D' Q  H9 b( x$ ]: l& N. c$ d' s
    stop- J" R( E, O  U* h) n$ y; g
  ]7 D1 L$ j5 P/ v. Z; ^! q# o6 |5 b

2 F9 q$ A# P: d" @' \9 m  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color! d. H6 E0 s& l$ O1 T, x1 W, N
  crt num-cars
( B4 X4 f( `2 s; Y2 I  [
& W8 x4 b7 A! X2 Z8 c* N    setup-cars
/ f2 O' |& E8 p) ?! l" R    set-car-color
3 z& |2 i- j+ Q4 w8 e! b2 m    record-data
! U& g: @+ S  _) h3 H6 s' Y( L  ]& `* T$ h- i# T0 e- ]

* y& n# X$ M( b% g: a  ;; give the turtles an initial speed
3 [, e' \: i$ K" O% r  ask turtles [ set-car-speed ]
& `% ?: y- z& c! X
; S2 [0 {3 e  h  reset-ticks
- L& r$ `& }7 m: U  D: Q% Uend3 w; V+ y& P4 ]  G, H
( K7 y2 L6 K6 ~8 M
;; Initialize the global variables to appropriate values
% \: z9 f+ A% \! Mto setup-globals
0 m% C1 ^: C9 t" t* v1 d  set current-light nobody ;; just for now, since there are no lights yet
+ F. l5 H$ H7 [6 y: u6 Z0 O$ x  set phase 0
8 J7 F* e8 @1 v4 f6 b0 W& d, V  set num-cars-stopped 0
* ?% @* h: [: v  i  set grid-x-inc world-width / grid-size-x
9 E* U: W" I) w8 O6 \9 C) i# ^6 u  set grid-y-inc world-height / grid-size-y
  G. m# k- u/ I9 Y2 g" X( r
& s, ^2 ~/ t9 T- _9 V: T3 V* h  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary, m1 w2 t, Z9 x1 @/ g
  set acceleration 0.099# q' E: x8 [- }& M* Y! H* K
end" K8 ~9 s5 v0 M- d2 q* y/ u

0 g/ g& X5 ^7 X8 N6 ~;; Make the patches have appropriate colors, set up the roads and intersections agentsets,: o6 p3 G6 K, `( e- H, ]8 F
;; and initialize the traffic lights to one setting+ b/ T" P( C2 ?, O1 T" |
to setup-patches
$ }5 S$ [- D" T2 e  ;; initialize the patch-owned variables and color the patches to a base-color
4 ~9 q" [  W) j3 @  ask patches% S; h8 M: P( Y  g
  [
9 |/ N8 A' k$ x. R6 h/ E  n    set intersection? false
0 }& A3 h3 w/ ]  m" W+ G    set auto? false. ]  {/ Z; ^2 S: ], [6 Y
    set green-light-up? true/ I7 k9 q1 C! r. L* D0 ^7 I
    set my-row -1
$ C' S  V+ u8 P, _. V. {    set my-column -1
7 N" u  k, B' X    set my-phase -1
* V' t* T7 |& F6 U2 x1 o4 k' w    set pcolor brown + 3$ ?/ @6 `( Y& `7 E3 w
  ]$ V4 C! ^3 G3 I" m
) i. G' F: z! u& l5 T& F, H
  ;; initialize the global variables that hold patch agentsets
6 i+ [: U/ K. R3 b# ?  set roads patches with
) ^+ X( Q- X( w+ H3 p" d: c    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or, n% W) Y7 W/ l2 F% z. q; a
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]3 x+ @8 u6 L8 e3 I% r
  set intersections roads with* W$ G. ?0 d+ ^
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
2 [( b% [( E* ]% X! S6 `  n2 b    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]: _. D3 O% z5 e" n/ U: _

- t% k* M3 z  Z9 ^5 t+ ~& s8 P" b  ask roads [ set pcolor white ]5 \3 T4 e3 H+ F. a7 Z: H/ R
    setup-intersections
5 J9 Q! r  X$ o3 w7 G$ ~/ R# ~# `, zend
7 f* M7 Y' y- `! d% \1 W4 m其中定义道路的句子,如下所示,是什么意思啊?
9 B3 N$ E& I! e+ ?2 Z" M* m# _ set roads patches with! h3 |! ]% d  q
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
( n/ w8 R0 n# A+ o5 B- D/ m: I* g    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]' T8 h! g' y* Y+ h3 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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