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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。
  {1 I4 x. v% x, j/ Fnetlogo自带的social science--traffic grid这一例子当中,3 g* c. E$ X$ B/ a
globals
7 ?: M7 ?0 b* }. E% i0 R/ a6 |5 W[) I- s! k! G+ _- T/ ]
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
9 i8 C$ F1 M- V+ v+ [  grid-y-inc               ;; the amount of patches in between two roads in the y direction1 X+ }9 u# W6 R) l5 o" Z
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
3 o2 ~& e3 w7 u                           ;; it is to accelerate or decelerate
0 e# q# y1 s* \1 l& d% G  phase                    ;; keeps track of the phase
  f$ [8 O' o+ E" g' J$ l  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure4 ^7 u5 y; \# m' N8 {- ?1 @
  current-light            ;; the currently selected light
  U: E; G) j0 x; b& |% j" @
8 a& e7 A) N7 H. d9 q! o5 L/ P$ p  ;; patch agentsets4 w6 o" g; }3 J' R
  intersections ;; agentset containing the patches that are intersections
) v/ ~3 u9 F, @; M$ V0 Z5 K; Q" W  roads         ;; agentset containing the patches that are roads. Q) D/ T. `% [. m% w1 A
]
# U6 I/ Z9 T( F  q# Z( m  g6 w+ E( S' b% f
turtles-own7 r" w* W& E; h  r; |  D3 m  M& a
[$ o% a' a1 Y" m! w4 V* j
  speed     ;; the speed of the turtle2 D1 u# s- c( |$ C
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
7 `  s  j) H4 {% @# I  wait-time ;; the amount of time since the last time a turtle has moved
; _) Q% Z* ^0 g7 Y8 ]1 C+ B$ z. K]
4 Y, ]7 r  K$ k4 U  `+ v3 \1 F3 l* x0 T, x
patches-own
) R: b" e# e6 \% s8 c[
: W  `9 w0 j9 w  M  intersection?   ;; true if the patch is at the intersection of two roads& |& K% K& f- U) I$ d: Y
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.9 C+ o0 k6 J0 O; `- m; U4 j& ~
                  ;; false for a non-intersection patches.( r: }$ S( P& B5 e# f5 u" s( P! V
  my-row          ;; the row of the intersection counting from the upper left corner of the
$ u7 O' H+ }* c& {5 m3 W4 Z                  ;; world.  -1 for non-intersection patches.
. }4 N4 l9 \# P6 N* g6 u  my-column       ;; the column of the intersection counting from the upper left corner of the
6 i2 C& h% A* G! S6 P                  ;; world.  -1 for non-intersection patches.0 F  }. ?0 n8 ~+ w2 e
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
: g# ^# P. O5 Z$ o! u  auto?           ;; whether or not this intersection will switch automatically." b) G5 n2 _6 s: g% F3 ^1 W
                  ;; false for non-intersection patches.' k" [( j! l% x: g
]
6 [' V1 d( Z  c% Q( o! e; o6 d5 f0 A$ B  ~5 }! O5 \, i8 d' E* a( z

9 v0 d; l7 V5 B. G; Q; Q/ r1 S2 D;;;;;;;;;;;;;;;;;;;;;;
$ Z4 O' S7 T0 C" F6 c; m;; Setup Procedures ;;& e/ o- t: }) M) P6 J" v: A
;;;;;;;;;;;;;;;;;;;;;;. q0 q5 n4 `6 I4 ]& o
$ U/ z5 k7 t* a4 e
;; Initialize the display by giving the global and patch variables initial values.
0 Q: F5 t) @6 p1 @+ [  Q+ [;; Create num-cars of turtles if there are enough road patches for one turtle to* S2 v4 @7 w5 q8 g, B1 |. l
;; be created per road patch. Set up the plots.
( _9 i" c* x5 z) E; q% y" Eto setup8 J" _) y: C3 A/ Q1 m! v; U
  ca
* k# |" d4 f$ w; |  setup-globals6 g4 C" p/ L8 |. Z; Y( G) g
5 [. }* M6 ~. Y$ _/ R9 r4 N2 ]
  ;; First we ask the patches to draw themselves and set up a few variables
9 N9 v. e9 \* c8 ?+ B  setup-patches
9 g9 {( @- Q' R- J  make-current one-of intersections
# k' h/ h3 D4 ]6 M8 S  label-current* n& n' D% B  D4 J2 f

0 w. L  ~9 V: R& Q5 e# \  set-default-shape turtles "car"
& I5 A) h7 r* N
2 S1 w) q2 L; `; |) H  if (num-cars > count roads)8 l( e0 s  |3 `
  [
2 K2 s: p, ]) I3 K    user-message (word "There are too many cars for the amount of "
5 S7 t" w- G$ N                       "road.  Either increase the amount of roads "
. f' i2 }2 u0 d5 q6 k                       "by increasing the GRID-SIZE-X or "
3 N4 p& v2 R/ K. k6 c* F                       "GRID-SIZE-Y sliders, or decrease the "' J# N+ }8 w- E; |' Z, o: k
                       "number of cars by lowering the NUMBER slider.\n"
6 L) U+ J/ n8 N! {# r                       "The setup has stopped.")
& T7 S' y; V  X% j4 t    stop
1 X2 [1 q1 E( G7 h1 \  ]
' P6 C6 h6 C, `3 p* |, }. c, g7 s
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
* z: q' |" l! @9 C( ~  crt num-cars, T+ Y3 _2 g8 h( {
  [- R! z2 c2 X. m: b6 L
    setup-cars6 F! a% }2 Q, \* _
    set-car-color) }- L0 F6 F4 T* q$ c  c+ ~
    record-data
# @8 U( w& k2 n* Y& }4 r/ Z6 X  ]
; m# I7 m- ?  }, I/ H0 V
) S5 I1 ^0 p9 v; c4 W  ;; give the turtles an initial speed
3 i0 r8 u: t) d. L" o  ask turtles [ set-car-speed ]  {* F& C8 e7 w; @6 [

+ `( S; Y4 A1 p2 ]8 B) ~9 k, \  reset-ticks
- x6 `5 O0 U* H8 E$ j; nend+ y8 }) X7 V$ m; E( l
* f& }. U3 n/ S9 x
;; Initialize the global variables to appropriate values
- Q' A" d$ W" w% _" b/ U% ^to setup-globals
2 n" F5 S0 T- C1 f. p  set current-light nobody ;; just for now, since there are no lights yet* F# r$ s  ?$ g% _; Q
  set phase 0
: w$ j# D. C- d$ C5 m. ?  set num-cars-stopped 05 D- H, @7 E: Y8 x- J
  set grid-x-inc world-width / grid-size-x
7 G% C6 X: a8 Y( t$ R4 L  set grid-y-inc world-height / grid-size-y
9 }* \, J+ S+ r* W9 i# V8 k8 e9 J* w1 T; f, \' Y# ]9 J8 @+ l* k
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
! m0 j% q  N- ~3 h) t  set acceleration 0.0991 f% l: |% `& f# U# k, B3 c1 \$ }
end  O( q% j4 i3 Q$ `3 y. [! f

% j5 l" ~3 R( w9 x6 s: a) K0 B;; Make the patches have appropriate colors, set up the roads and intersections agentsets,9 O9 Q* I( K1 A# g0 Z
;; and initialize the traffic lights to one setting
- K6 ~: g% _6 C0 q5 ^to setup-patches
  o$ N# X9 E2 C3 V7 e3 r  ;; initialize the patch-owned variables and color the patches to a base-color
! T0 z3 @/ H) k/ D) O5 L  ask patches7 ~! A( m9 L! T/ ]. j
  [4 Q: h) ~$ @, [+ {
    set intersection? false
$ `6 y2 r, Z. k+ U  s) a6 C    set auto? false
. ^) d2 F$ f5 S& z    set green-light-up? true
% b7 e: g9 U, m0 Z( W    set my-row -1, V5 e4 l" M. J9 H# S
    set my-column -1. p" i! k: ]2 |& F$ Y
    set my-phase -1
4 b# ]+ n# z2 E1 G6 [9 J$ I    set pcolor brown + 3; h2 e0 p' n$ K
  ]
2 U8 I' Y" e" g! X, k  M% y# f: b
# ~( k/ F2 [% Y5 a% M, i9 L  ~  ;; initialize the global variables that hold patch agentsets0 p$ Y& Q( ~3 y) a; ]
  set roads patches with( R: R6 O  F: S+ _4 i3 ?! ?
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
! z) ?: X; r$ H) r8 C) \! [    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
5 k- V) F/ n+ ]' [$ n  set intersections roads with3 ^0 ~( u+ X6 h& O+ f
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and" N* S4 y4 F" w- Q* Q& e  M4 ~5 C, |
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
. j5 E. C! w+ B. ?4 B/ {% L' b1 v! H# `, N1 m: I" ]
  ask roads [ set pcolor white ]3 U' p! m! s0 J
    setup-intersections
! I& N" s% b) }! l& }end
/ ]4 z% b3 a. _6 I+ X* Q其中定义道路的句子,如下所示,是什么意思啊?: T( }8 i7 ~5 w, K4 R9 I' j
set roads patches with6 U) x) `/ a0 I; ~
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or3 t4 x1 _& Q  I1 X; v- |  d0 g+ Z
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]. @3 R! d5 p3 e# o( ]$ 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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