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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。
" P! ^. n+ c% F* V( y# U) d, Fnetlogo自带的social science--traffic grid这一例子当中,. `9 g) v1 e: r  s4 S6 m4 g: `
globals3 F9 q, G+ U7 @& j3 v" X3 V5 [
[
" C$ F  h; R& ^% N5 R( W6 ~' ]  grid-x-inc               ;; the amount of patches in between two roads in the x direction
& y+ e8 i7 j! }, k: p1 N0 _+ x  grid-y-inc               ;; the amount of patches in between two roads in the y direction
) q4 a& p" F9 {& G, f* e  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
! b: p  }  Z7 s8 S4 H, A                           ;; it is to accelerate or decelerate
) x% p+ y; ^/ S4 \/ Q5 r  phase                    ;; keeps track of the phase" [+ ?8 _0 |0 {6 L+ {- C& K
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure1 h) r; `! `9 M& E4 D; }/ Y
  current-light            ;; the currently selected light
! {8 Z) R/ V) o+ C' U( k: x0 Z3 k1 [1 B$ A  e' e7 U6 q1 J8 {
  ;; patch agentsets
4 C' k( }8 \0 O( \8 i# m4 T: d  intersections ;; agentset containing the patches that are intersections
( P. L7 K* l' Y! w3 X2 Z: r2 v  roads         ;; agentset containing the patches that are roads
6 b8 ?, p/ E: h* e& Z9 F* T2 ~9 f]
* f  [. P0 Y" R3 |, ^4 k# Q, }/ i) L+ r* i$ Y% P
turtles-own; d! ]7 r% Z0 N; k
[
9 }4 A5 g) l3 }+ B! {# o  speed     ;; the speed of the turtle  Z4 E% d8 `. I1 K1 @' @: z
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
0 q9 k7 d: O1 w* `% H, C- [  wait-time ;; the amount of time since the last time a turtle has moved
7 z4 [# F4 B7 P]
* K- J4 l" Z  |5 M/ F- i. Q0 B9 A0 H0 v" ?6 X
patches-own
& O7 R& c+ r3 q  H8 H[
( h2 n; n+ y! v7 p9 D  intersection?   ;; true if the patch is at the intersection of two roads
! p: Q8 I: D# Q! |4 l  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.5 g% k' ]( }: ^; H2 u% u8 x9 j
                  ;; false for a non-intersection patches.+ D8 u: n5 I& `) G+ v
  my-row          ;; the row of the intersection counting from the upper left corner of the8 G/ ], }1 l% n
                  ;; world.  -1 for non-intersection patches.2 m6 N1 E4 |- j: t
  my-column       ;; the column of the intersection counting from the upper left corner of the
# x* M. a2 E# T- j                  ;; world.  -1 for non-intersection patches./ _5 @- \) a  v9 I
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.0 ]8 N+ P( W( P' N7 {3 L; ?
  auto?           ;; whether or not this intersection will switch automatically.& v, L4 f- t. {( J0 t  q0 U& X9 S
                  ;; false for non-intersection patches.- d$ q8 u# z- k9 g2 b+ C5 ^& _
]  P+ ]2 g# v5 _1 I

4 b$ M4 @7 w! K( V, E+ a
& |2 l1 h4 X& R( R* z;;;;;;;;;;;;;;;;;;;;;;
& Z  }9 t) h$ m4 j; T;; Setup Procedures ;;
, G3 b4 x6 I" k' d;;;;;;;;;;;;;;;;;;;;;;  m) `1 A# Z! Q4 U

& ?7 v. |1 N7 Z;; Initialize the display by giving the global and patch variables initial values.
$ L& L6 q2 q( j5 ]  K;; Create num-cars of turtles if there are enough road patches for one turtle to5 ?  W+ P$ Z; |9 U' a! I/ l( N
;; be created per road patch. Set up the plots.
% z& ^' L$ \$ b! O' v4 F5 Fto setup$ Q/ W9 {; [, }9 I: R# W% F% c
  ca
% D. b8 {" u4 ~* @4 g8 l  setup-globals& Q! x) e+ U0 E5 _) P, F% N
( O5 c  C2 x" X+ c5 b& L
  ;; First we ask the patches to draw themselves and set up a few variables2 {( n  _8 R7 c. C; c0 j: Y
  setup-patches
# D  c% z& k0 R3 y# `  make-current one-of intersections9 ^0 R2 a5 T: _% R5 f( e) u
  label-current
' O  t2 v) d2 c- C4 H$ v/ P) M# ^- R$ D% O, B1 K
  set-default-shape turtles "car"& d; n# n9 w5 @: g  n3 ?- o' O
0 ^/ A6 T0 P* ]( x9 O
  if (num-cars > count roads)5 S" U8 B3 X: S1 X* _& [2 J
  [1 }& s8 ~& M, @  ^, ?0 l; s
    user-message (word "There are too many cars for the amount of "
9 \7 `9 _3 z! J) l) {                       "road.  Either increase the amount of roads "* y# ]+ S& k; v3 r2 U2 H
                       "by increasing the GRID-SIZE-X or "
6 o, D1 ]% u, K' b# j                       "GRID-SIZE-Y sliders, or decrease the "
! T- p) b. [. ?6 M# x7 m0 e                       "number of cars by lowering the NUMBER slider.\n"
5 V7 c" U8 T/ K5 Z9 m0 u                       "The setup has stopped.")( b1 D0 D5 E# r! m) Q( I8 P
    stop$ \+ A! m6 x8 ]& x8 F0 i8 z
  ]. G: w" j* k  z$ _

1 A7 U: b: ^% `7 q, `& _  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
* ]% i$ K# v$ U7 m5 F/ |, T  crt num-cars
% n+ l+ j# X2 i" x3 A/ w' D" B: J8 m  [4 O( P- a# E* E+ u9 E/ ^
    setup-cars
: T9 j1 F( O% j) F9 q; s# b/ H% c    set-car-color
/ g' Q! m6 P& {% R% k2 Q& [    record-data0 G9 a( v- H7 Y1 M; W
  ]0 o) d& f3 F3 A) w
. n) @, Y& b2 e- O: b" N
  ;; give the turtles an initial speed
0 A! Q+ b, q, d" Y4 A  ask turtles [ set-car-speed ]3 A+ i3 E9 K$ S" v! J3 @

  l. {) F# c* g  reset-ticks
% B. R8 n* P4 O6 p' }end3 N5 a% b- d1 Q

2 g! l: W1 n5 `9 t; Q;; Initialize the global variables to appropriate values1 {6 S" I. u: ]
to setup-globals
3 \6 S" G2 g/ ?3 u9 t  set current-light nobody ;; just for now, since there are no lights yet
! [, P  x* L9 I) B; S4 U+ ^) D6 Z  set phase 0
( k8 ^8 Q! |" O' A% m. ]  set num-cars-stopped 0# x2 ^, i, g5 p6 @. Y
  set grid-x-inc world-width / grid-size-x9 ?2 t' t- H6 o+ P+ C& M
  set grid-y-inc world-height / grid-size-y! G$ i6 K0 J, J6 f9 d

2 x0 Y; b! C7 x$ \; u  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary% S& Q0 U/ g4 L% ?8 E" ]9 C8 F
  set acceleration 0.099
  Y. o7 M* M9 I: K& i& Y0 {  p/ rend8 [; j; C3 D5 w/ ?/ h7 N
4 I* @5 L4 ]$ L
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
3 g# x2 U2 h: _- ^) r, _;; and initialize the traffic lights to one setting
! U) _: H& N; {$ g; ito setup-patches
5 N; E( D% G  O/ W& P9 r. B: s9 {2 P  ;; initialize the patch-owned variables and color the patches to a base-color
  x% t& {& `/ w' P6 L) n0 R  ask patches. p0 z8 ]* N0 t8 H- t' O- H
  [+ E+ H, q0 t% @3 J
    set intersection? false
+ j' Z& X8 o; h: H# C# x    set auto? false0 {, Y3 u7 M. R4 Z, w  J
    set green-light-up? true
  k8 j3 n4 `  A$ @    set my-row -1
; u. f3 l% m& V; G% g    set my-column -19 s# c$ G% P" c( S1 E7 n
    set my-phase -1
# l) r* _% J0 ~% _# Z- l0 h    set pcolor brown + 3
! _# I$ R1 J* d) }8 @9 S; h  ]
4 p. l6 Y5 [% U3 h3 v
( x; h3 s! q/ V) r  ;; initialize the global variables that hold patch agentsets
+ P0 x5 e) H, _4 m- i4 }0 [+ V- L) I  set roads patches with
8 r; F/ }1 A5 w/ g    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or: S& T, `) t  W- Q: q
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
  l- V& k3 i* A4 s( t  set intersections roads with
5 `! k. v6 w, z) {' P    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and( g* {) f" I7 C
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
6 ?7 q/ {4 J+ Y' ]. @; r
4 Y  y3 E1 q  v  ask roads [ set pcolor white ]+ L, W4 B3 c, _' l+ j  y: a
    setup-intersections
. I' q: d' ]3 B/ V1 [+ }/ J1 e. Qend
4 o% P. x1 Z: a8 y: `" f, C0 ]其中定义道路的句子,如下所示,是什么意思啊?; |9 f8 m$ a% N7 t
set roads patches with
6 Z  i2 r- h& |$ w2 j    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or" N' W' m4 n6 f! ]$ _8 Q
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]& N$ I7 Q, h  v: 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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