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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。
3 N% t: P. A0 P0 N* N7 A) Wnetlogo自带的social science--traffic grid这一例子当中,( j; Y/ a- s, |* P
globals( T  Z" B6 i9 D8 K4 f1 S! C* J
[
% w) P1 ]5 s/ F5 o) c2 \6 J+ T  grid-x-inc               ;; the amount of patches in between two roads in the x direction
2 |  M* [4 o) ?# p- v) P: C  grid-y-inc               ;; the amount of patches in between two roads in the y direction
0 E7 T0 D" f  H; V; ]  acceleration             ;; the constant that controls how much a car speeds up or slows down by if. X2 N& h$ y' P9 U9 R6 L
                           ;; it is to accelerate or decelerate
- E9 G: D: ?& |  phase                    ;; keeps track of the phase
1 {* |$ M! X# t  i  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
% ~6 h" U% |; U! I; U8 i  E  current-light            ;; the currently selected light
/ a5 y" Z" c$ W7 |8 Q# _+ B
* m4 e% r. [9 v; h; T, W  ;; patch agentsets! t$ }# {( ?! [$ h$ `
  intersections ;; agentset containing the patches that are intersections
3 X2 ~/ a* F/ w+ o, U4 k+ y0 v$ f  roads         ;; agentset containing the patches that are roads
  k# \, e# F" J. z  J0 t& }7 O* @]
4 s/ C/ @/ ]+ C  V" ^/ L2 A; m# B/ T% B, |
turtles-own
5 s5 C# w* |. U- ?" r. U[
; T8 V( i6 d( B  x" A5 D  speed     ;; the speed of the turtle+ Z6 Y% z* G5 W- k+ Y
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
7 ~2 P' F3 k2 C. i3 P5 [0 m/ E" o  wait-time ;; the amount of time since the last time a turtle has moved4 S/ s1 O2 ^8 E) q
]
# G0 a: v$ V. s5 B" ], \# p( ?& l  s
patches-own6 d: Y4 S8 U% m
[0 [3 Z. ^0 v( h9 @+ ~
  intersection?   ;; true if the patch is at the intersection of two roads
! [- o7 W% N! ~1 u1 u6 V  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
6 j' U0 V) G/ ^- ?. X                  ;; false for a non-intersection patches.; h# ~+ h( V* L: A
  my-row          ;; the row of the intersection counting from the upper left corner of the
) L! J3 A. J4 Z% ^% l5 B* k7 }2 Q                  ;; world.  -1 for non-intersection patches.
  J+ i% M' @9 U3 ?; X% X. [" ^9 u  my-column       ;; the column of the intersection counting from the upper left corner of the
0 P+ F8 y4 z: y0 }/ @& {4 g                  ;; world.  -1 for non-intersection patches.# m  o0 b$ [4 s$ ]3 ?8 ?
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
2 I6 Y% {& v5 B' C9 B- Q' ~; I. H; K  auto?           ;; whether or not this intersection will switch automatically.5 {3 a- p! M0 L- k- D: L2 o
                  ;; false for non-intersection patches.
: v* \3 I. C4 B9 ]5 ?5 i+ j; s% i]0 L: [, a$ C: a4 o- N* O2 A
2 L& F; }% F. ?9 k/ Q6 x
: a( }' ]2 Q0 r0 o7 u* k! ^6 U
;;;;;;;;;;;;;;;;;;;;;;! h+ I" R7 h' M1 G& D' e
;; Setup Procedures ;;
/ D! w( n" t) h6 ~;;;;;;;;;;;;;;;;;;;;;;) M/ f5 ?3 R4 `- \

* a* F8 S6 R3 A* G+ Z- [$ k9 l;; Initialize the display by giving the global and patch variables initial values.
, i, `6 _, y( Q5 p) ^  E;; Create num-cars of turtles if there are enough road patches for one turtle to
1 C& V5 G2 h6 x; E% A;; be created per road patch. Set up the plots.' I. m8 w2 ?) ^. x- f! a
to setup
) t& C- ?) V9 g  ca
  \7 x+ y: n- ~- E  setup-globals6 e* P; w8 c5 G3 d2 `$ J+ m6 k
% Y3 U# v8 c- W% j3 W. k7 ?
  ;; First we ask the patches to draw themselves and set up a few variables
; O/ l" h& u& A9 L  setup-patches3 Q% g9 w! }7 `2 e- C" T
  make-current one-of intersections
4 F' V  ~9 b$ H/ t4 v3 k6 e2 r  label-current) D  u8 Y& `& T! ^$ d* g2 B& w
' J% X$ m2 v2 r; U0 z5 x
  set-default-shape turtles "car"' k8 Y# z: Y4 i8 A! J: c1 C, `
- c5 I1 w( H/ s/ z
  if (num-cars > count roads)8 ^: O' u; Q4 Z5 W6 q0 ~
  [8 N3 e+ L: W$ p) w
    user-message (word "There are too many cars for the amount of "" b( x6 c5 z% ~# ^$ ]7 ^1 m2 M: B
                       "road.  Either increase the amount of roads "
) ?* t+ B, u( H# [! \& W0 v2 s  m                       "by increasing the GRID-SIZE-X or "
8 G0 P2 [2 i9 [+ V+ W- O- i                       "GRID-SIZE-Y sliders, or decrease the "/ e& ?! M1 n9 _0 e. R4 ]
                       "number of cars by lowering the NUMBER slider.\n"( B8 }% i3 b5 y$ g! p) U
                       "The setup has stopped.")
6 {' r+ I0 }& M; ^* b. a1 V3 N    stop$ }% C6 ?8 _9 }3 r" O" ]! D3 Q+ s
  ]8 j* w2 ]. S& i" G- y* n$ {, H0 c
% m( o# ]$ f7 B& l; `0 |3 T
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color8 b- k- d$ P4 U3 I6 f6 I( S4 w" @
  crt num-cars
: V8 s) c% @! W, y( y7 l  [
  D6 F% T# N( i7 g& q- J: w, I    setup-cars; R# l# D  E( {4 S0 u( u+ W
    set-car-color
/ Z/ S0 f3 }( k    record-data
7 n5 N) y& y9 `$ j4 e  ]
. `* u+ a! f7 l3 j: m+ i
( O$ ^9 W7 o: J; E' N0 n4 y/ K* @  ;; give the turtles an initial speed3 y4 v) s; `+ F& ^
  ask turtles [ set-car-speed ]! p9 R/ E- E% @& P" ]3 R2 l9 x

! K; X1 f2 ^  Q& n# r0 ?  reset-ticks7 u0 Z" `+ Q  h6 u# S& E! X
end2 l" _2 S4 l# z8 [, X  B5 T

1 u" g/ v& ~, |" T;; Initialize the global variables to appropriate values
% E, d% W$ Y0 ]9 J8 Hto setup-globals
0 ]6 {. l& P$ ?' T$ T3 d  set current-light nobody ;; just for now, since there are no lights yet
- i( u7 [6 s6 o& v$ }! p' L  set phase 0& t# E& D, `' m7 m, ~* A
  set num-cars-stopped 0
, K+ ^7 u' R( D. d/ U# `  set grid-x-inc world-width / grid-size-x: `7 }2 R* ~/ W; A1 K
  set grid-y-inc world-height / grid-size-y
, B4 k6 N6 s7 `! x7 D
! h3 _( Y7 N. }9 [$ o* Q. K$ m! F  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary# E* c+ @2 C, `5 Z# J" D2 Q
  set acceleration 0.099
/ I( T9 W, b" ~9 v; l) L! b# o0 W$ \end9 g4 Z- _: ^/ ]- j0 s. D

: t  Z$ \9 k9 J$ Q( P6 X;; Make the patches have appropriate colors, set up the roads and intersections agentsets,9 u9 N- H# X2 e* t2 X1 M
;; and initialize the traffic lights to one setting
) ^- L6 E* b% D8 L2 qto setup-patches
: H0 @0 m; T2 `- a  ;; initialize the patch-owned variables and color the patches to a base-color
, Y2 J- A5 l% R- `; r  ask patches
# g0 z* a' X* [" O+ b4 O1 n: {  [+ L+ }" a" l' d  O3 M7 e7 G
    set intersection? false% }6 }- j2 P0 `$ w
    set auto? false
* ~1 [5 G" N; e$ j6 m0 L    set green-light-up? true: t; q* W* H1 Z! c- J* Q
    set my-row -14 _# J$ z5 S2 T0 z2 y; m! e9 Z& m# r
    set my-column -1% G4 O2 l, a( W2 G/ H, A- c
    set my-phase -1
1 s3 Z) r( {; w/ E6 h. O( e. J) w    set pcolor brown + 3
; K6 G  ^: w. t, B  ]
5 R* g; m/ T' X# z
) F/ q1 e1 j7 _! L; e* z8 @  ;; initialize the global variables that hold patch agentsets; e+ z) p0 `$ K6 W8 D
  set roads patches with1 }3 P' x6 G" T' b! J6 B
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
! H9 D$ P* H( a5 Z- o    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
, `8 |% t/ I9 ^' ^1 L. n+ X  set intersections roads with5 }/ ]- t" d- p5 E  Z: S0 V# _
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
3 S: t+ N- L. @0 ?  A( D+ a    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
) F; `2 h1 b  K* A/ o5 d, [7 j5 i: J  v; ]7 ~( ^3 s
  ask roads [ set pcolor white ]
1 _! i1 Z6 P& o" p    setup-intersections
6 N9 h5 Q% J5 c) t9 Xend
8 A1 q, V3 }. [% H) g8 a其中定义道路的句子,如下所示,是什么意思啊?- j9 @. }4 r0 z5 h
set roads patches with
# C6 A! L$ B5 g3 b    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
: ^7 Y3 P1 I: v/ y" U5 S    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
% n$ y) h" _8 d% z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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