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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。
: I0 f' \& d" P+ g4 H0 L, onetlogo自带的social science--traffic grid这一例子当中,
7 y  K- |8 N. ^  z# ^globals
8 s8 ?0 a9 S2 A6 Q5 y/ {- G& b[" H* @: Z8 c, Z( a
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
+ a$ s9 q( z/ C9 z! k  grid-y-inc               ;; the amount of patches in between two roads in the y direction4 [/ W( C3 k/ a4 ]/ d2 M& T
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
# @4 u4 x- n; G                           ;; it is to accelerate or decelerate# i7 w4 z& z9 D, W  f
  phase                    ;; keeps track of the phase
0 r1 I- [# D7 ~8 B2 W* M+ u' O  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
! \$ K0 a3 d4 A) I, `' ~  current-light            ;; the currently selected light
4 V' R4 p* f. a1 r' e2 F8 a- l, i. S" E: ~: {) j. M+ ~
  ;; patch agentsets0 `& y7 _! _" Y) e& ~! T
  intersections ;; agentset containing the patches that are intersections
* O8 y# h% W: Q; d* g2 s; X4 ]  roads         ;; agentset containing the patches that are roads0 t) n8 u  |; b; l
]" x( I4 O- i5 S

% h2 R" i. V8 h$ }; Nturtles-own
, k# Z8 L- ~7 T! a& \[
/ u% N. H) ]# a( z1 t  v  speed     ;; the speed of the turtle% q- x8 ]) b. s( S% |" e2 f+ b) e* G
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
- Z: h) u( j5 P8 I: Q/ q/ J  wait-time ;; the amount of time since the last time a turtle has moved" s+ Q5 C6 r! h
]
% _8 \- f* C* I) Q- q7 a/ q7 ], ~) @6 m3 h
patches-own5 H( ~& p0 `) _! n" p  R# J% {7 J
[6 F1 k# s! T; N; o3 N. ?" @  ]9 L- d
  intersection?   ;; true if the patch is at the intersection of two roads
( Q! z" m/ s/ C" A  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.5 c5 x+ k2 U* D. B
                  ;; false for a non-intersection patches.
" L; L. B! `+ t: j8 k& _  my-row          ;; the row of the intersection counting from the upper left corner of the
( }* H$ W5 L' W( r                  ;; world.  -1 for non-intersection patches.! \0 V0 q( n" M- A( C
  my-column       ;; the column of the intersection counting from the upper left corner of the$ Q2 g  G9 h) \6 R6 ]0 ^8 I
                  ;; world.  -1 for non-intersection patches.) V0 ^  U5 d6 A! q: z
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.8 f4 P( E2 @; i# L
  auto?           ;; whether or not this intersection will switch automatically.% N1 l) p, _; x
                  ;; false for non-intersection patches.2 N# g3 d! F( N" e  E, `
]
  H% w* O( J; F' C* q6 F/ t
  @5 u6 l' V; l& e$ f4 l# d: K5 G  B" P; m/ o
;;;;;;;;;;;;;;;;;;;;;;
6 ?8 u  p' P4 a2 a0 R" y( c; J;; Setup Procedures ;;, p. Y$ M6 x5 W6 I
;;;;;;;;;;;;;;;;;;;;;;
' F0 @, \' q4 g
4 D3 h. b- W1 g;; Initialize the display by giving the global and patch variables initial values.# H7 q; G9 k' t+ [+ Q! V% I% l
;; Create num-cars of turtles if there are enough road patches for one turtle to' x# Q; O( w5 d, [3 {( q) Q/ U, w
;; be created per road patch. Set up the plots.* \3 Y& g8 e  z  n9 I
to setup! h. c/ g8 B4 Q- S% i3 g
  ca
" b& T7 l. D7 W5 N# m  setup-globals
+ K" ?5 A5 L0 k  x) z
3 Y, Z$ j+ H) P: K1 |# d4 F  ;; First we ask the patches to draw themselves and set up a few variables/ d8 K9 V$ z8 D# D5 v
  setup-patches
) r) A( S& i* H) {5 v" {  make-current one-of intersections
+ Z3 }0 L) _" D  label-current
( D  s( }1 [# `0 R4 z+ }1 N; A/ p6 l5 d/ K
  set-default-shape turtles "car"
6 v/ p) `$ ~, y! L
3 W, _4 l. t% P  if (num-cars > count roads); e6 S+ A6 z  o
  [2 F4 ]+ S! Z& A; {
    user-message (word "There are too many cars for the amount of "0 Y! U+ I3 N4 s& M( ^( I( _
                       "road.  Either increase the amount of roads "
$ T0 @7 f# G; K; K! Z# y  }9 J                       "by increasing the GRID-SIZE-X or "( f/ x/ `5 {* ^) I" N7 w" e
                       "GRID-SIZE-Y sliders, or decrease the "( r# X5 m* r3 [& ^5 K
                       "number of cars by lowering the NUMBER slider.\n"3 ^0 y6 e% Y) I+ z- q' [7 a4 N
                       "The setup has stopped.")% N* [7 X: Z% r: f6 O3 N
    stop
4 R" f6 @6 J) B9 `, _. C5 D  ]
4 }$ c7 e( R+ [/ D$ [, E5 ]2 d6 r" ^
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
: u5 e. z4 U4 j5 K  A1 U  crt num-cars
/ b% D& o3 [8 e/ u, y# o  [2 y8 O7 S* m* b3 G: f1 L; n6 R$ e  g
    setup-cars8 N  I. r9 P& ]
    set-car-color
# I* R, _( e: [& o7 A    record-data
5 u% d* u; r- W! W6 W0 h6 B$ p  ]
; N! U# O' F: \; z! G8 m
* Y  S. R) L: E. e% m; `; ]) |  ;; give the turtles an initial speed4 O) r. f+ N+ l1 {0 h$ y9 l8 R' ^
  ask turtles [ set-car-speed ]
' c7 z1 m7 }( E. r2 I8 ~4 t: D+ {6 `; x# F9 [9 _
  reset-ticks8 W9 R% {" s) D! a  }; p% B
end2 {: \% K2 }0 ?% h$ N2 `
, N* a7 X: y7 ]) }
;; Initialize the global variables to appropriate values7 ]8 S+ j% s8 H1 N+ c/ g, x' e
to setup-globals
5 \6 }- E2 e9 u2 b  set current-light nobody ;; just for now, since there are no lights yet- b; Z# E$ `8 V$ u9 m
  set phase 0
* D2 }# k- F- B# W4 }: q8 T  set num-cars-stopped 0( n$ K+ E' G* ~1 N: y+ }6 I
  set grid-x-inc world-width / grid-size-x/ {3 K9 w% ~9 {# [
  set grid-y-inc world-height / grid-size-y
' ]; `1 @. P+ v1 O" |
& ]1 C/ I, F! `! e  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary, h  [8 M( D5 V
  set acceleration 0.099
- G) X2 ~0 S3 Z) F3 hend
: s: g4 p( o% E! ]. |$ B* d1 k1 a: D# ^
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
' g% F3 q& T# B1 q. V: e" p;; and initialize the traffic lights to one setting
, m- `2 h3 a8 v8 U7 a" ^to setup-patches
8 a6 A+ j, F* ?1 W; t- o# r  ;; initialize the patch-owned variables and color the patches to a base-color9 o- M. G7 P5 _& a+ Y- t5 ~9 j9 B9 ~
  ask patches5 e( u0 l6 K0 F$ q8 {2 |6 Y: U
  [
4 p, I% Z: A  X# |    set intersection? false" ^- G" e: x! [! w6 K5 s
    set auto? false$ E: s! S' Y+ O5 x
    set green-light-up? true) B4 W% ^$ |3 _5 y% c0 t3 \, w# H
    set my-row -1
) `+ y' s+ {, Y# w9 C2 a# B    set my-column -1
  @! X" F) {$ p0 ]- t    set my-phase -1/ E! @1 S* x# u$ v0 P# z, X$ _4 D
    set pcolor brown + 3' }) K! r# _# _% j
  ]' Z. \+ N6 s9 W$ F2 ^/ b) t

( N& z" ~. A, M' p9 f7 [2 P; R/ Y! s4 f  ;; initialize the global variables that hold patch agentsets) m! t( r% }, C$ B3 [
  set roads patches with
7 I5 ^) ~# D- [! Y) G! Z# ]    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or3 j* M% ~$ k: J7 p* d
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]& s' T' h  A: q' Y
  set intersections roads with- u  F( F# I2 K
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and6 u# K! C; e: R
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)], Y3 K/ g2 ]$ Z, m# K% X3 H+ u
  h' h4 _/ N1 Q! V! v% C" @. w
  ask roads [ set pcolor white ]
0 W  S/ r. Q( ^+ a- }+ `    setup-intersections. n/ H3 {& a  ^6 P1 ]( Z8 K8 o( N6 u
end( y' F. z; _0 k, I
其中定义道路的句子,如下所示,是什么意思啊?( p4 O/ y% d* L
set roads patches with
0 A5 M2 `6 Z* Y9 C3 n, J* x2 E! m    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or. }2 n2 b  m4 r- K$ f
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]2 \4 U9 T1 e( A; d3 o
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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