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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。
% U1 W  J# L5 T4 U- H0 ]6 ]5 `/ K/ Enetlogo自带的social science--traffic grid这一例子当中,
$ F; u$ F4 D% X8 O, N. kglobals$ z( x# `9 q8 U6 {; I9 a$ y
[
) y! i- z9 _! I  grid-x-inc               ;; the amount of patches in between two roads in the x direction
. H& e- ^' L- @  grid-y-inc               ;; the amount of patches in between two roads in the y direction/ h9 p, H* w; m2 [1 O
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if9 r( ~  R4 r, W* I
                           ;; it is to accelerate or decelerate& N2 t7 d# U! V+ Z
  phase                    ;; keeps track of the phase
" d  v5 g* y4 O0 K  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure) L' K3 z! @( p0 k( V
  current-light            ;; the currently selected light* [0 q( Q0 T# z3 |

! S  G- }1 l" c0 k  ;; patch agentsets
# b- s% D6 \5 F6 p" h1 g( N. w2 c9 X  intersections ;; agentset containing the patches that are intersections
6 C& }" b& t) C/ }4 W  roads         ;; agentset containing the patches that are roads5 o: W1 e* w; V: t$ v
]# o4 Y: [% Z$ x5 D3 u" u

  e+ @% L) ]4 f: R9 ]turtles-own, o8 u# ]6 `) _( O1 w
[
) m9 S  C! _+ K* |0 r7 l  speed     ;; the speed of the turtle
1 P% C& ?6 B1 h# `( M  up-car?   ;; true if the turtle moves downwards and false if it moves to the right& u2 L1 m. M  `- |% O
  wait-time ;; the amount of time since the last time a turtle has moved9 {9 p1 j4 K; Q# A
]  x- g6 k6 v, [$ a3 j0 P

! ]& Q2 s& ^" bpatches-own; |+ n2 M2 E8 z3 S; W- M, ], M& Y5 D" h
[
8 x* B  O8 Y) m9 ~  intersection?   ;; true if the patch is at the intersection of two roads' L6 r+ O0 w) `! ]( F
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.% z. R6 y6 h+ @/ W' C1 t0 V# L
                  ;; false for a non-intersection patches.
% t2 ~+ i- @' s5 o  my-row          ;; the row of the intersection counting from the upper left corner of the
1 T- J, a/ O8 `4 h                  ;; world.  -1 for non-intersection patches.1 O! {& ~& U' K. Z3 q
  my-column       ;; the column of the intersection counting from the upper left corner of the
% T3 [9 k! R, N0 `) e  h+ t" J                  ;; world.  -1 for non-intersection patches.
4 H" }* M( |& E/ b. u2 k+ R  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
/ a6 J9 Y: S9 k; p1 i  auto?           ;; whether or not this intersection will switch automatically.# T+ P) y4 o& ]' ?
                  ;; false for non-intersection patches.5 p1 s: w- j3 _; `. z' O, v7 N
]
! _" o+ j4 ]. Q& T
) b9 I% d2 C( \1 }- A7 L) Z' {, r* v; d* ^7 k
;;;;;;;;;;;;;;;;;;;;;;
$ u4 q- m; _* J) r7 S4 c;; Setup Procedures ;;
$ t) ?0 T* g. @;;;;;;;;;;;;;;;;;;;;;;& ^+ d) A8 m5 n1 d6 ~% B% A) g" B
. O- ?& P1 E. V' f* G
;; Initialize the display by giving the global and patch variables initial values.
' ~1 y& \6 \$ ~2 O, S- R$ _;; Create num-cars of turtles if there are enough road patches for one turtle to
, {- @9 E8 p! V$ s: c;; be created per road patch. Set up the plots.$ B& S* ^2 C2 f9 ~% n
to setup
- C$ s( O  n( D$ Q6 Z/ c* W- }  ca  O6 C: A9 E9 X& z6 h
  setup-globals
7 B8 R& }5 n! R& A' _" r# P
* l3 w' Q/ P! Z: t7 l1 A$ M( t  ;; First we ask the patches to draw themselves and set up a few variables
, @: a3 C* L; D1 t4 k: t  setup-patches
0 F  L1 k. k1 f2 S+ W  make-current one-of intersections
  e( K  |  H! n" V1 w' |* F2 N  label-current
# j+ m# |0 p4 E2 `
% j' p3 j" g# b( H8 i/ i' R  set-default-shape turtles "car"5 N% G+ r' |& n5 a( q2 }
! g, Y9 A+ G9 P
  if (num-cars > count roads)
: D9 C4 j8 v! v/ o  w6 m+ w  [
# R2 f- V' g$ J: m9 ~6 _    user-message (word "There are too many cars for the amount of "% o5 D  |+ S; R+ G
                       "road.  Either increase the amount of roads "" g, \/ J; j) E( l
                       "by increasing the GRID-SIZE-X or "# B8 C! M2 v1 K% h7 k; ~& U# s
                       "GRID-SIZE-Y sliders, or decrease the "
) B' C7 u$ [9 @7 P                       "number of cars by lowering the NUMBER slider.\n"- w. v( I% K2 E6 A6 {# j
                       "The setup has stopped.")# u7 k& f! L* J
    stop# t3 N) Y6 d' o
  ]
. ~' H* x. _: b
) B' `/ ]" G* j/ W1 T1 _  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
0 g6 h  r; s1 S( w  crt num-cars
5 w/ T! @' u: q- ~  [
7 ?2 E$ s1 `: Q7 b    setup-cars3 b; o- x! a0 G; g$ _
    set-car-color0 S) _+ k! J& h( R7 c
    record-data
8 @( i' r: z4 ?6 B0 ?  ]$ @, ~. X& e0 |% ?# ?
5 |4 i& H0 D8 ?6 F9 i5 Y% {2 }
  ;; give the turtles an initial speed
9 C8 D5 h& c* L  j* {+ s5 I  ask turtles [ set-car-speed ]# k: ^; _' ^/ N  N. J' j

3 a4 I* J7 V: ?5 {$ w  reset-ticks0 u! Y0 C6 R; G
end
# ]* u7 e" M1 H6 S  h4 Z# |
' S7 R( Z6 y+ s* B;; Initialize the global variables to appropriate values9 a: v) o9 n. Y) V
to setup-globals
* Y- I, X/ |# A& O8 L# a  set current-light nobody ;; just for now, since there are no lights yet
8 V5 [6 P. G$ n. G6 p  set phase 0
% T  U+ j+ R4 v" l: [  set num-cars-stopped 09 j0 L7 T  Y5 Q7 \2 I! L2 l
  set grid-x-inc world-width / grid-size-x
0 V  j+ t( L6 e% T* T  set grid-y-inc world-height / grid-size-y
7 B  p6 a& i# Z! |/ h" Q! y' p) Q+ h" G9 `
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
5 A' ~" b# ?; D0 p4 ?  set acceleration 0.0996 _' M, H0 h9 {. A
end
4 E, c1 Z& ?2 A: L5 c
% k3 D+ L" _0 y( ^8 K' w4 m0 H6 U5 n' l;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
2 D2 N& u" U  d+ j;; and initialize the traffic lights to one setting
% U7 V' p! P1 j9 M. }. A4 ^to setup-patches
9 o9 j  N- a& D2 ^' @2 q7 P" S% f6 p  ;; initialize the patch-owned variables and color the patches to a base-color
+ {/ |, H8 b9 `) y1 \2 r3 [' E4 O. S  z  ask patches
" L: I2 M2 v8 ^$ R& S! g3 y% C  [( \: ?! ?$ j: D( _6 z+ ?5 w
    set intersection? false: p+ s2 K2 x" e4 }+ `9 u
    set auto? false
6 s& e* M4 k  n: U7 {% ]' b( u  d, a    set green-light-up? true
0 C# |8 r  n3 N  l    set my-row -1. I7 r: Z* }6 h+ d" b# |' {+ ?9 [
    set my-column -1* p! e/ a2 |; a7 h/ f
    set my-phase -1
0 {" x* e1 d1 f+ V4 [    set pcolor brown + 39 i, b3 ?* b( ^+ ^
  ]4 _0 Z/ B# t  _, G% m' N( d1 W) l: s$ V5 W3 {
. |# w. J5 F: K* B1 Q6 Q
  ;; initialize the global variables that hold patch agentsets2 v; K3 [; e4 y1 e
  set roads patches with
/ M) `' T9 ^4 z  p* X    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
5 m. W  R# Z* x" m9 y/ ~3 U# g    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
1 k' \: H1 X1 c# g  set intersections roads with
9 k9 {# {. |- O    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and, m3 ]0 x% t. S0 Z% |
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]- g3 ^( c/ V( N" }' t8 n0 B
% S6 e+ X  O7 a" r9 K) C6 Y
  ask roads [ set pcolor white ]
$ q& _# D& i% o5 m# j9 C    setup-intersections- x$ t0 C, K3 K* {0 R0 M* j' A
end
( A/ \' \, `$ X8 Q4 y其中定义道路的句子,如下所示,是什么意思啊?$ j: T8 ^; w7 j9 b
set roads patches with
" n5 S0 F$ d: b; P    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or& W0 Y8 R. m2 o$ J
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
" @$ I% ^8 }, v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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