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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。
! Y) ]1 `9 O4 _( i9 V( n6 W' Knetlogo自带的social science--traffic grid这一例子当中,9 N! D/ }' @9 u. S4 R# x" v5 O2 n
globals1 O7 E9 p7 B; A* G. D- G( V
[
# k: M& {! r3 g) U  grid-x-inc               ;; the amount of patches in between two roads in the x direction; w4 ~( k  k5 L3 ~5 s
  grid-y-inc               ;; the amount of patches in between two roads in the y direction$ T5 j$ i3 M: X) i
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if- i, ~  b6 g$ S3 V4 M- L* M
                           ;; it is to accelerate or decelerate, Y8 m! _0 H! {$ ?# o
  phase                    ;; keeps track of the phase8 }: c& w* h4 }8 s
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
# i! Q  Y/ V( L1 h  current-light            ;; the currently selected light
! _9 \! i( [( M& q( B) B+ t* I% P" F! I1 n5 n! m7 h
  ;; patch agentsets, Q2 M' _' ]0 Z- i7 u3 z3 _/ s) t
  intersections ;; agentset containing the patches that are intersections: G  o- H& i( w' X
  roads         ;; agentset containing the patches that are roads, }$ P- B. a5 o$ s
]7 c6 y4 Z4 ?9 Q
  A" @. o( ~, h5 M8 o, }
turtles-own
' F" i" v; I7 V4 `; U8 k! m  ^[0 D( t# Q( |( M" r, ?
  speed     ;; the speed of the turtle
/ a. \4 P* Q* o1 G8 g! S* R4 v  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
4 ^. N6 J0 e% f+ m% u) Y  wait-time ;; the amount of time since the last time a turtle has moved- i; I0 G5 H  Z6 I) P& L
]$ @2 L: i! e1 w8 u- [" p: ]0 w
. q6 Q$ x3 L* ?# h6 `: c# Z
patches-own' X# L: b6 S' Z* [
[# A2 q: Q# g7 n3 _$ h: w
  intersection?   ;; true if the patch is at the intersection of two roads! v9 Y1 q  {: L, b/ K
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.* B5 C4 I' {' C& N2 E* C' I
                  ;; false for a non-intersection patches.
% a0 l  {" |9 Z* ~+ T8 I  my-row          ;; the row of the intersection counting from the upper left corner of the1 s4 l! e: O& u: U- u+ Q  K1 M
                  ;; world.  -1 for non-intersection patches.
% O3 a& I8 }2 w6 F6 b4 b  my-column       ;; the column of the intersection counting from the upper left corner of the! @  E! D9 z5 H6 x% Q8 j
                  ;; world.  -1 for non-intersection patches.9 v2 ]( y; J# ~; \& f7 s6 R% d
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.' R. F/ e5 @8 @- C
  auto?           ;; whether or not this intersection will switch automatically.( o- J- j% H3 E$ g8 u5 N
                  ;; false for non-intersection patches.
5 [- v6 b8 H& t0 a/ i% }]
3 x2 d8 A# ]  I# \. ^' ~& Z' M, S& U/ ?, O6 p, l: m# [

' X) q; K- F! z8 k;;;;;;;;;;;;;;;;;;;;;;
4 q  M! W5 f( U;; Setup Procedures ;;
# S3 P" `4 g  z& r3 r8 G;;;;;;;;;;;;;;;;;;;;;;! d, o' {  N2 u2 @/ A: W9 c7 I3 ]
3 j+ U8 @4 B# n! `4 S7 ?
;; Initialize the display by giving the global and patch variables initial values.
& s. e& i# ^, V; S;; Create num-cars of turtles if there are enough road patches for one turtle to2 _! a. @: U: `5 [
;; be created per road patch. Set up the plots.0 y: a0 \5 v3 }3 Q% E
to setup
0 a" Q' g( ^3 W  ca- C) g- l* q9 ]. [; j( ?
  setup-globals4 l4 }4 ]* v+ C9 ~/ v

+ c4 v6 \" l: b- g$ O  ;; First we ask the patches to draw themselves and set up a few variables3 H' @3 U! _! g9 C% P1 Z
  setup-patches
+ i  S% J( z" S& P0 R. T' p  make-current one-of intersections
, Y9 Q, S1 T# q) w* }: @' \  label-current
- {# l& }: H+ v1 r. `" G$ k: w' O% B/ Y2 \
  set-default-shape turtles "car"
# O2 l- e6 }5 b0 k) e) K7 K$ z. B5 i1 K. G, n4 @, R$ m* I6 t
  if (num-cars > count roads)
( _. ^6 \+ k  v8 D; D" a/ _  [# B, n. e$ V7 S) u" ]
    user-message (word "There are too many cars for the amount of "
; r# V5 p* M& d% E3 O                       "road.  Either increase the amount of roads "
; C% Z4 N; X: d' D                       "by increasing the GRID-SIZE-X or "
0 t$ j0 s4 r0 K; R3 A$ x3 E                       "GRID-SIZE-Y sliders, or decrease the "
) h: T! S) S6 I, ]% G6 p! z                       "number of cars by lowering the NUMBER slider.\n": Z: K0 H3 L0 J& m) A- R
                       "The setup has stopped.")
8 v' F: S' L$ J+ k0 l3 \9 t8 {    stop
# r9 f9 N6 w6 A  ]7 L) @" @# a  K, j4 k( i+ h; s, S
$ X5 }( g6 A; r# R: ?% n0 n4 J
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color8 \( k- z! e5 G! H$ {; j( A
  crt num-cars  G4 [6 U! t# o1 j
  [; t% D7 V4 C$ y
    setup-cars
, \! h( X0 n4 F+ g0 P. _    set-car-color1 N% p* [3 R8 N# @8 Q1 n
    record-data0 z, B3 r9 o0 X# q. I
  ]
: h  Z& k7 ~5 S: r& {7 Y4 f" q
' D1 F: G& C! t6 O" p. p  ;; give the turtles an initial speed
, B2 ^/ H0 a9 O0 q  b' B  ask turtles [ set-car-speed ]; n7 v# P4 t" P* c7 ]

- f# t6 Q7 M) o! Y3 a: L$ I  reset-ticks
" G+ K8 @9 v  U+ Iend
9 B5 |  x  h( l* O. C- w8 A3 ~2 C
4 b9 |1 S& y! W8 h0 X;; Initialize the global variables to appropriate values
# [% C+ u* _9 X6 h* Fto setup-globals
" D5 Z( t! @" J% E! k8 F/ p. g  set current-light nobody ;; just for now, since there are no lights yet
5 d- d' o& y/ h6 T  [4 c* D/ J" x9 i0 H  set phase 0! I, D- l! b/ K6 _4 _- p  ~
  set num-cars-stopped 0
" k0 y5 [1 [) F, p  set grid-x-inc world-width / grid-size-x( I) i1 C. I5 Z" l
  set grid-y-inc world-height / grid-size-y, Q+ k/ I9 D$ i# W( f0 z3 _# k

# `, W8 q0 V4 W% w' p1 j# s  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
  `* L* s& v4 ]1 X3 V( S2 r  set acceleration 0.099  P( b2 f/ k; e. i
end! T, t* s3 S7 u, O. d' f2 d3 o

/ ~7 T: ?9 n' p+ ^* B3 ~;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
* S2 K1 T7 T2 S+ p6 h$ A;; and initialize the traffic lights to one setting
* h! b/ u' K' O- l4 [to setup-patches- X. U& b- `) F7 k( [- @
  ;; initialize the patch-owned variables and color the patches to a base-color
' c. q7 C8 K" m& d. X" N  ask patches9 K, a: g# k6 n3 o& M* o) `
  [
0 G* K, O" X" g% L2 u2 Y    set intersection? false
# K+ w' X$ x7 [2 M: m8 X7 q    set auto? false5 Y( V& \* b9 ?0 s
    set green-light-up? true$ d9 P( z4 y/ g3 e4 `9 _
    set my-row -10 ~  h* D3 L- z; Q9 V% _) L
    set my-column -14 z$ c" C. ]2 E6 K. F" k- `) k
    set my-phase -1$ ~5 ?3 i4 W, r/ v, e
    set pcolor brown + 3$ z/ z  k- Y) ^6 c7 ^2 K+ B
  ]
( d5 m2 G. b& r9 g0 _6 t. e, g$ i( I' Y8 G! f
  ;; initialize the global variables that hold patch agentsets0 Z- B3 p/ u# J' q$ \# u  n, ~
  set roads patches with
0 Z/ ^2 {2 i+ X3 I4 h3 e3 v7 W    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
8 M# G+ K( H, v) S% ~* Z1 [! Q    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]1 ~- l& f; C6 X# n
  set intersections roads with
' B  |1 b' z& {9 t+ u/ `9 v    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and6 \6 @; C+ e4 m0 b
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
% Q  N" L/ y) K: P- \1 ]) j, V- ?) u; x8 c* z6 E5 f9 o
  ask roads [ set pcolor white ]! b* D! _+ N. a
    setup-intersections- `" d/ ?  i' k$ w5 {
end. _! y3 {3 h7 a1 {/ }- @
其中定义道路的句子,如下所示,是什么意思啊?1 p8 ?3 i/ I& `0 P# ?3 O
set roads patches with1 ~/ P- q0 c" K6 w& g0 B
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
4 Q& t# G: I* _    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
+ }( Q; s' J9 J9 J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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