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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。
) g3 [# O- e  nnetlogo自带的social science--traffic grid这一例子当中,
. l! W" c3 ]) \/ B9 B  s7 }globals+ [& X4 A, [: }. [2 T! O5 s& M
[
4 Q& Y- B2 P+ k6 k/ i" I# m3 N) Q  grid-x-inc               ;; the amount of patches in between two roads in the x direction6 j& X( B& ]3 P" u; m9 x
  grid-y-inc               ;; the amount of patches in between two roads in the y direction" K- o0 R( ?  {* J1 N- r! ?4 u
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
0 p5 u/ r( `% h" l8 P                           ;; it is to accelerate or decelerate* h0 i1 D. V% r% _# S" Q( Q
  phase                    ;; keeps track of the phase/ z+ O' c, B0 N% t' [$ l
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure  F4 R" f4 U( D; V8 @( e. Y2 W
  current-light            ;; the currently selected light
$ x: x1 {6 O- S1 D3 f: r& z5 J! P9 n  N
  ;; patch agentsets& c1 ~6 O) m8 k! M- K# p8 y6 D
  intersections ;; agentset containing the patches that are intersections8 i) Q! i0 M$ L+ P% E: \
  roads         ;; agentset containing the patches that are roads
# J5 M- C+ a' `$ X! G" A]+ ]8 `6 R+ Q" f, Y3 A
5 n4 G( l  W4 P0 c# X! F  q+ @5 m7 C
turtles-own+ V8 r( S+ d/ l: N/ r7 e
[
+ j! N+ _$ V: n1 e. [1 c0 ]& B  speed     ;; the speed of the turtle+ {: ^7 n% @. R+ W
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
7 E0 |# `# d% k4 U) X3 O' [: m  wait-time ;; the amount of time since the last time a turtle has moved- }9 k% ~, v# P9 P4 C; p# S: G
]' J: C' }3 v% H; v9 E
! v  H* @* w" }3 u
patches-own( p' {& x6 k/ _# m
[
$ ^* q9 I- U6 Y' J: c# N8 m# l7 P  intersection?   ;; true if the patch is at the intersection of two roads
1 S4 G8 Y1 d9 S  v0 P- H4 R  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.* A' V5 p! N5 ?
                  ;; false for a non-intersection patches.! M$ e8 q$ Z- v7 L$ z
  my-row          ;; the row of the intersection counting from the upper left corner of the2 N) n" q# v6 I3 z
                  ;; world.  -1 for non-intersection patches.
# I) C3 ^+ }$ o4 H4 w" P  my-column       ;; the column of the intersection counting from the upper left corner of the6 {3 M' \, R. i
                  ;; world.  -1 for non-intersection patches.
, P# H, m1 q& i+ V& e  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
9 R& E% l1 @0 U0 k$ t8 e  auto?           ;; whether or not this intersection will switch automatically.
: F0 q  J, B1 T+ N* Y                  ;; false for non-intersection patches.
: F0 H# k- Q; r! U" T6 }- g]6 U% J5 p9 E8 m7 d* H( H

$ b, |3 r" X0 [' m# U$ K0 B2 R% r* J9 `" _; T$ c  L$ b
;;;;;;;;;;;;;;;;;;;;;;
; Q( U( r. d( n2 `;; Setup Procedures ;;
! {& U8 D$ T) \) l;;;;;;;;;;;;;;;;;;;;;;  z) C" \4 e; t3 a# ^; L

9 z' ^- u, r, k4 j;; Initialize the display by giving the global and patch variables initial values.# ]( D& n/ e! V+ d3 a  v
;; Create num-cars of turtles if there are enough road patches for one turtle to; N; H: ~: B5 F( u
;; be created per road patch. Set up the plots.' v( ?- C* C* G+ M, l  h( r; n- k! W
to setup# x! x/ j+ M5 t( c& `' m
  ca, V/ Q) L0 u# X
  setup-globals+ O- l5 L! ?) \3 N# X% W

$ m) `- K7 g& `8 r+ s. d2 @# H6 T+ f; K  ;; First we ask the patches to draw themselves and set up a few variables
5 G9 q( H% m# T, T  v- ?4 u) u7 H  setup-patches
6 l8 W; R  ^. S6 ~  make-current one-of intersections
7 a9 R, U4 a! \  label-current+ \0 Q! g7 `! A! E8 I& k; R0 w
" s2 D% b4 y* X3 v, A6 C
  set-default-shape turtles "car"# L, y( w2 n" h: C; g
1 m. {8 `8 I' q) U0 ^5 e9 I
  if (num-cars > count roads)4 P$ e' _. q- C0 C4 v' d3 r$ X
  [- T: o: r, A  Y: x, e) R  S9 j
    user-message (word "There are too many cars for the amount of "* L; i% S; O: ^8 p- O7 z; t, i
                       "road.  Either increase the amount of roads "8 H% R" P( h4 Q9 S( h
                       "by increasing the GRID-SIZE-X or ": Z! L! |& S8 @0 ^6 K) k0 Q" B; C
                       "GRID-SIZE-Y sliders, or decrease the "
- C5 l4 B: E/ c* z1 {                       "number of cars by lowering the NUMBER slider.\n"1 q9 F7 S; i5 o. W) |8 O) e& z
                       "The setup has stopped.")
9 k) I" X8 A$ Q! _  c    stop* E2 R. p& }! r! R9 N' ~1 V
  ]! c* r. a; r1 ]! U2 h

# O/ K3 E* K# A9 V1 A/ y  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
) ~3 L& b; T( s7 X5 |+ p5 {  crt num-cars
2 ?' ~# j0 D8 V' v) ^3 I4 s  [1 B& r7 ]7 }0 T6 R" T; e% _9 p9 K5 G
    setup-cars
( ^6 N3 U' P0 Y& |; v6 _* E    set-car-color
  `* I7 S! d9 Y    record-data
  O$ W; p8 F" b$ `  ]1 m- E; O; U" K9 f3 x, \+ o. t

; b4 f- P- v( D( i1 F9 A' u5 r  ;; give the turtles an initial speed% B; I( o& b2 F: u! h: y
  ask turtles [ set-car-speed ]
5 H& L  B5 G6 }7 z  `$ G: ^# N/ @' `7 S% q  A
  reset-ticks
. N# y. {1 O& r1 `end9 i. w8 }0 l+ v" J# D6 m/ x6 ~+ v$ K

1 M$ b: }  r2 e- ^1 w$ V;; Initialize the global variables to appropriate values
- y; m: U' n  Lto setup-globals5 ^! e6 ]: [) k) Q( m' W& |8 [5 D
  set current-light nobody ;; just for now, since there are no lights yet
. |. p- b' R8 d  X+ E. b  set phase 0/ K$ K, a" N& C* G8 o! N
  set num-cars-stopped 0
- r) C6 V) y6 G* N% R. @  set grid-x-inc world-width / grid-size-x: I5 E8 T! E6 E( p- K) l8 T" A
  set grid-y-inc world-height / grid-size-y3 `* F& n6 P6 J* P# z/ H

" p3 G7 T/ F- H  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary* [- y$ f  C$ Z' p% ^8 O6 k
  set acceleration 0.099
( m5 k6 x0 E* Uend
( B5 ?+ g/ h) U0 j- j; S
+ |4 H$ G% \7 r( p7 P;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
$ q5 O- m3 E7 E' H" H;; and initialize the traffic lights to one setting5 [9 g) G7 N0 `* o
to setup-patches4 M$ }1 M) ]8 ]- x9 \( _
  ;; initialize the patch-owned variables and color the patches to a base-color- u8 B5 P1 y" F1 Y  v2 w
  ask patches' l; {1 h3 K. o2 f9 B0 Z
  [
# L$ g0 ]0 O" M  a- ]    set intersection? false/ ~3 E" X4 v+ z% [/ \) W
    set auto? false
* p0 C% |$ O  B/ h    set green-light-up? true
  J8 Q( j7 W) ]% s    set my-row -1- {, k$ y* i  l9 N, R  a
    set my-column -12 Z0 R2 b9 \( G  W  z9 Y. r+ n
    set my-phase -1
4 z0 U* S! w% J* {2 Q; G7 N# k    set pcolor brown + 39 G5 w* Z8 B1 Q
  ]
: e! r" D8 w3 H! x8 j9 b! j2 P/ m% O" h  h/ t7 j2 m% @3 k
  ;; initialize the global variables that hold patch agentsets
9 a$ r. y  h' Y  set roads patches with, e( j3 u1 W2 v) s" c8 h1 u. A& |
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
; z/ Q# l( v8 K5 x% K    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
' c5 [: @; ]5 M% ~& m  set intersections roads with
% p: Q3 V) S5 k  B    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and9 a# B! T+ E( l! Q6 h" m1 p% g
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]5 E/ ^( @# l6 X* z" c) {
9 g" n8 {3 @$ U+ i/ ~# t1 h
  ask roads [ set pcolor white ]
; W0 ]2 n( g3 i1 a    setup-intersections
& ]5 l1 k# w) r8 Send: B% |1 o, d* {0 t8 t4 {
其中定义道路的句子,如下所示,是什么意思啊?" h* y9 a" w0 Y. m
set roads patches with& f* N0 h: |/ c, G4 \0 B  Y
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or: R, u0 E, t5 {" _( l; Z
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
4 k6 b( n  g2 n$ g/ n$ H) p+ ^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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