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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 t3 c, x% s$ B+ W+ E+ Wnetlogo自带的social science--traffic grid这一例子当中,( }6 _( q9 {; S6 Z  C- h5 G$ c3 N
globals& e4 }0 e6 A  W. T- c
[; A7 S, S- P, w) R  O4 [( \' P
  grid-x-inc               ;; the amount of patches in between two roads in the x direction; X  l  K. j0 ?1 T- A) k" h
  grid-y-inc               ;; the amount of patches in between two roads in the y direction
1 n+ @' Q- C) G; R  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
* q5 }7 K' K. W" k3 B' a* p                           ;; it is to accelerate or decelerate
% p2 `. I7 C# @" \8 K1 W  phase                    ;; keeps track of the phase
. S/ S2 l" Y# q% @$ e, H- s$ h+ M  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure/ m2 ^7 g8 N  ]
  current-light            ;; the currently selected light
. F: u( g0 B' C" ?2 _; ?- x- d1 X3 V' u, g$ B
  ;; patch agentsets- P# }- y) @/ ]( c
  intersections ;; agentset containing the patches that are intersections8 _7 T+ g9 I' j" H/ ~: o: Q$ N
  roads         ;; agentset containing the patches that are roads! B2 E( G* `4 A$ D  o" z; h
]! q* _8 d/ w. l; h
8 C  Q: N2 [) R/ q% r
turtles-own' c: x  U$ E! }; `0 i) b9 b
[/ h! i  E& Q( i+ x# {
  speed     ;; the speed of the turtle# P# l* W9 i; `, D% g2 T+ U+ m
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
4 L, z" v) ?* z% e  wait-time ;; the amount of time since the last time a turtle has moved- H6 D* T) ~* p2 Y
]
3 a  ?! j! v( F4 v) Y$ H3 E) C$ _  ]1 G8 B" Y) `2 ?
patches-own- x9 g  V1 @3 D; p% f
[
6 m! P3 g  T0 f/ D; U# G" p  intersection?   ;; true if the patch is at the intersection of two roads. Q3 E7 M5 r3 g$ `$ ?/ K$ w6 V
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.& i+ E# Q0 p$ C' o
                  ;; false for a non-intersection patches.
- G% b: B  {. C9 g8 W" |/ [6 E' f' z5 R  my-row          ;; the row of the intersection counting from the upper left corner of the8 t- p- B( m  w0 o* u
                  ;; world.  -1 for non-intersection patches., x% J: i+ v$ h* P: @% r
  my-column       ;; the column of the intersection counting from the upper left corner of the
, w4 Q9 |/ ?" `, f; {' z                  ;; world.  -1 for non-intersection patches.
: N4 W, U; ~1 Q/ _+ D4 M% A* H  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.: ]# `6 a' @" ^3 f
  auto?           ;; whether or not this intersection will switch automatically.
0 r1 y" G5 Z$ a( h- s; ^' P                  ;; false for non-intersection patches.
: y6 Z- {6 G9 ~4 f]7 `! {) t8 P# A$ B' I% G. }5 T

+ X' w* L  T$ q3 L6 C, Y" Z* p5 P' k" d! _
;;;;;;;;;;;;;;;;;;;;;;
# c9 X0 o- T) p1 c( F;; Setup Procedures ;;
7 E! H( @+ {2 o6 T$ J# E;;;;;;;;;;;;;;;;;;;;;;
- @) B% Q) |; w* ^/ x: t1 i% d* ]4 J7 H/ M8 f& |6 t5 _
;; Initialize the display by giving the global and patch variables initial values.: j7 h- j9 a. n( b8 V! v6 Y
;; Create num-cars of turtles if there are enough road patches for one turtle to% ~  W) i+ a( \1 p9 C
;; be created per road patch. Set up the plots.
( M$ L3 H5 w$ l9 vto setup
  U) q. ~! [2 C) y, z  ca, E& c( k7 Z  f! N
  setup-globals
3 N7 n5 n) g& A1 m# c. L- I: u* h7 P" d; z
  ;; First we ask the patches to draw themselves and set up a few variables4 U, }$ T( z4 o' v; b, z0 Z
  setup-patches
, o) Q# `% \6 C8 Y# o4 Q; N  make-current one-of intersections8 M( [. l) K. `3 N$ r
  label-current
, [, B, a* Z% ?4 T" k
- Q) v. |$ a' K% x7 A; A  set-default-shape turtles "car"
. d- t8 J4 {: l% c3 }) ~8 @: L
9 l9 q! k- z! n  if (num-cars > count roads)  ?8 R2 {) [* p7 X4 {) n
  [3 H4 G5 [& _+ N4 Q, I" J1 u
    user-message (word "There are too many cars for the amount of "
! o- {( P6 z1 ]) c" s                       "road.  Either increase the amount of roads "
8 u! q. J( U5 }- L                       "by increasing the GRID-SIZE-X or "$ }( }& Y. I; Y0 C6 C1 ?
                       "GRID-SIZE-Y sliders, or decrease the "0 f; T- e4 o3 \0 x7 K2 p
                       "number of cars by lowering the NUMBER slider.\n"
/ b# F) D/ u! Q                       "The setup has stopped.")
9 ?5 ?; |& T, L$ N    stop
6 z! `% r. V2 B6 l9 F  ]( c( x' D. V+ ~1 o4 Q
- `; }# Z0 e4 `% x: f9 Q% k) m4 U
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
8 r/ t" P& M6 h& o6 y  crt num-cars8 R' K- |7 w; a8 O
  [
! m1 T5 O1 W9 c5 r4 Z" N5 K    setup-cars* \: Z2 H7 ?  l$ A& }$ W2 {
    set-car-color
+ D2 S. B) g8 Y, \    record-data" K# K2 W9 T5 p0 [9 D* Z) z/ j
  ]6 V6 L) N- r) Q7 \. `

, Q1 M4 k( M% x0 M* r  ;; give the turtles an initial speed  g0 X6 o$ H3 \/ |. ]3 a
  ask turtles [ set-car-speed ]8 s3 Q  O, ^( s& u
9 p  ?* r; \4 x$ m
  reset-ticks: i6 g+ I; K- n1 N4 m' m
end  {# D" c5 Q5 y
6 U" O. e7 w% h2 q
;; Initialize the global variables to appropriate values* t% _' L2 v$ f
to setup-globals: Y; I1 {) @, A! N; @- D
  set current-light nobody ;; just for now, since there are no lights yet; b8 U  T7 R; C( b
  set phase 0  ]8 z, D0 U; C4 O. R1 b" x7 U
  set num-cars-stopped 0! n4 k' P# A' S- Y  f! O8 F% h7 B
  set grid-x-inc world-width / grid-size-x
9 S* j. A, ]* l  set grid-y-inc world-height / grid-size-y' P0 n, }( s5 s, B1 g4 [6 r. h0 ^

: k5 z; U4 r) A  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary) v, x8 z" m2 r0 a* _3 D
  set acceleration 0.099  Z+ Z1 F+ m! ?5 S# I9 q) L4 W
end* o4 W& w( t8 j/ P4 g% o' ^& U: f% k
9 z5 v, g5 `  I* B0 l5 s! B
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,. X, `! M( M" D' G* j2 k  h
;; and initialize the traffic lights to one setting2 ~' m; [- ?3 d) i6 M) |/ z
to setup-patches
% y$ V. s( ~2 _( W: V6 v  ;; initialize the patch-owned variables and color the patches to a base-color/ p% \. P+ t0 Y. c
  ask patches
% A. n, I) e1 o  p  [
% F- }$ n4 l5 b& S( j6 [! l    set intersection? false: j) Y6 f$ a" w, z- t% I. g) H0 L
    set auto? false
6 j  [* k) C- [( f* l8 p# h    set green-light-up? true/ j/ s6 W4 E2 G! Y
    set my-row -1
( ]6 {" P5 P( {0 C( W    set my-column -1
8 B& x* J6 \- _3 ?  D0 t    set my-phase -1
4 V! o/ I( h# w" [# v    set pcolor brown + 3+ ~0 Y% x, S4 V8 ?1 u* A5 s9 I. P
  ]: z8 I7 p/ q+ O4 A# G% _

: f* v$ z% b; L8 H/ |7 V/ z1 J  ;; initialize the global variables that hold patch agentsets/ J  H5 l( U' ~) W8 y7 h
  set roads patches with; I: w) B. C1 O8 X( A# _
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or. |- W( b$ Y# V8 F9 X
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]% ^: d5 D0 X& v+ }4 `0 o
  set intersections roads with
: M# _. A+ W, E' k& m    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and, Q4 A' l( F$ m+ V, a- g& h
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
1 M7 b% t8 o; R$ N* R5 Z
- S( d& S2 p5 Q3 B- A  ask roads [ set pcolor white ]
& F9 x: ?: j- `6 F  O  h7 @    setup-intersections! @/ E) t% h. u5 P$ W$ l# O; J
end
3 Y" g% F8 u6 u9 X- z0 `3 d! y其中定义道路的句子,如下所示,是什么意思啊?3 Z' D+ Q0 b3 H/ I
set roads patches with! z" L: |3 Y8 S. ]
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or' @- Z4 d- l) v, l+ j* X3 }
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]$ R$ f. Z$ V& E
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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