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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。
/ j" f7 E9 j' Tnetlogo自带的social science--traffic grid这一例子当中,5 p7 |6 U$ t. \! y) c
globals
( y% G" w; d7 N: E8 g[* R& F, v* U& N
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
9 t, a4 H+ q' n. a+ [3 t  grid-y-inc               ;; the amount of patches in between two roads in the y direction
3 ~3 Y5 j1 ?+ i' U, i  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
: n+ E3 s& G, a4 u                           ;; it is to accelerate or decelerate9 r. U2 {# q& B0 a" v2 X3 a8 ?3 G
  phase                    ;; keeps track of the phase) ]" f  M9 X+ t) b' B) m
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
! _- ]( Q8 ^7 [! |9 J  current-light            ;; the currently selected light# P1 G0 ^: n/ a! c( o/ L' ^" ~. X

0 H# y  p' n2 w6 L$ {  ;; patch agentsets
. O0 r! d2 _1 k9 `5 Z  intersections ;; agentset containing the patches that are intersections
( e8 K# K% Q- u. E: D  roads         ;; agentset containing the patches that are roads
' g8 N; d5 a1 B5 V+ p/ D  ^1 Y]
8 `+ ]$ X7 j% M1 V; s4 ^7 e8 T( O! ?
turtles-own
8 a* L& K2 ]) ~* F% y[
2 p. r( J" `( ~, v  speed     ;; the speed of the turtle
- L4 G+ m# ?4 r  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
: S' J7 [! }6 R+ x- r  p  wait-time ;; the amount of time since the last time a turtle has moved5 W* E. a6 P8 \8 t- q6 h
]2 N8 J* V7 j3 Y+ W9 A0 ]; X

8 T: @/ M5 Y+ O' V1 H) A% Zpatches-own
% y/ n6 L' I/ O& I/ H0 j[5 w! F9 }5 ]; K; c
  intersection?   ;; true if the patch is at the intersection of two roads
3 @+ Z, h" K9 L  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.; I; Y+ q( O% {+ H2 W$ _
                  ;; false for a non-intersection patches.
1 `! C, b% p/ j  v  my-row          ;; the row of the intersection counting from the upper left corner of the
8 [- c" p* C: e" I! k                  ;; world.  -1 for non-intersection patches.
& P* ^/ t: ^6 N6 G' Q  my-column       ;; the column of the intersection counting from the upper left corner of the
$ h) {" U, O4 m, W; N6 X& x' |% [% u& {                  ;; world.  -1 for non-intersection patches.. H+ Z8 R/ D4 o/ m8 O
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.2 F& X! W! S3 e5 P: a5 [
  auto?           ;; whether or not this intersection will switch automatically., a0 z  l+ y& q. f( m; d
                  ;; false for non-intersection patches.
1 [+ N. m" b' m]
, n. K$ A4 X( ]: J% c4 Y$ p0 c3 d- V) `) D2 ^2 B1 x
# [1 F) \8 s* f- b
;;;;;;;;;;;;;;;;;;;;;;! F# \" P6 g# z' @9 ~1 e& p+ x
;; Setup Procedures ;;
! }; @) n; N- o;;;;;;;;;;;;;;;;;;;;;;
; W; \& r# U: W/ M% i; S0 D4 P- K+ }
;; Initialize the display by giving the global and patch variables initial values.
. O# f# }! z2 @+ V' m;; Create num-cars of turtles if there are enough road patches for one turtle to
7 ]/ Q7 k9 Q% Q  ?  E) C# e;; be created per road patch. Set up the plots.
( D" m6 d& G! p! ~# cto setup
7 i7 ]" a1 h& [  ca% n% r* I( F/ r# U. f
  setup-globals$ W- o: s, G% _2 ~- y, P* o
  {5 w0 e3 Z, ?  ^4 u# c5 ]7 ?
  ;; First we ask the patches to draw themselves and set up a few variables
1 S5 n" z7 [/ \' E. `! e6 @  setup-patches
$ m) h8 j4 y% l% e1 I  S/ _3 r0 ?  make-current one-of intersections7 T7 n" C4 W, S3 @$ x) T' d
  label-current
$ |5 M0 m; ^. R: X3 v
0 A+ A8 Y7 _4 L  m" u' t  set-default-shape turtles "car"
+ B3 ^0 v( }- J. K" X4 r+ t% J3 V, q6 z. g/ _1 L
  if (num-cars > count roads)
7 I$ c7 o" t% O0 q% A# d. T# f  [
' A* x2 @! `+ U    user-message (word "There are too many cars for the amount of "6 X& P5 v, k9 o! Q/ `/ [
                       "road.  Either increase the amount of roads "+ m7 C1 E- n7 x5 m  M
                       "by increasing the GRID-SIZE-X or "& ?# W" F8 f0 ^3 p$ n0 [# _
                       "GRID-SIZE-Y sliders, or decrease the "
1 t: R! P4 a( v                       "number of cars by lowering the NUMBER slider.\n"2 x! G' g  b9 ?6 r! f  D8 R
                       "The setup has stopped.")
: y- s: z$ M9 }2 K, Y- ?7 O4 `    stop
& V+ |! N' @9 n; P  ]
3 K4 e" x& X3 t) f! R3 I- K- }% `: C, _$ v0 w
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
# p- A6 b1 P( N) O  crt num-cars
! w3 S' ]5 S# b* X  [0 L5 j  }5 a! e, [1 C- ~: g
    setup-cars
! C2 ~# c5 o8 }/ h; J" G    set-car-color3 y" @+ ]2 }4 u- k5 W/ T
    record-data9 z, X9 b' P- G. y# E$ F
  ]
4 k6 d3 o7 z5 e- m# ?7 p% _. a' `7 o/ @' @+ M
  ;; give the turtles an initial speed5 \" s( R: p5 _5 b" Z4 l8 d
  ask turtles [ set-car-speed ]* \0 o* G$ B& v$ p% B# P2 B+ _& c
# Z& e( E: Q" P
  reset-ticks9 f' L/ Q5 q4 T; \- r
end
) T# P7 q+ t# D
+ X2 ?3 t% L! k;; Initialize the global variables to appropriate values
1 E2 K8 J2 ~+ t. r. c4 S; O5 vto setup-globals
0 l% m/ c3 Q& Q. s  set current-light nobody ;; just for now, since there are no lights yet
6 @- Y9 p, H$ r7 G; U  set phase 05 n; N* g3 Z0 f1 o
  set num-cars-stopped 0; q* F% R' `5 Z/ E4 t
  set grid-x-inc world-width / grid-size-x. e/ k0 X1 B- t( }9 q; Y$ A
  set grid-y-inc world-height / grid-size-y+ \8 d6 m6 _% B% {0 M( S9 u2 D
- D# f/ l  j% I) x* w
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary* u" R, l. i1 T8 T1 T
  set acceleration 0.099- O' W1 k3 s) `. s! @# V5 I4 ~
end/ I4 ]+ L" d- M. W* I0 w  r6 k
$ E/ o' Q$ ?. h
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,# s+ j) p& t6 X5 A8 t# {3 o" _
;; and initialize the traffic lights to one setting$ L) n0 v- q6 j9 P1 B# w2 B
to setup-patches( S* K8 d) C5 E8 W* G, }( B3 j
  ;; initialize the patch-owned variables and color the patches to a base-color
& H7 w$ C0 W" B$ q  B  ask patches3 _2 [) i2 U4 A
  [
( U2 T. w4 g- @5 }    set intersection? false" F, y+ c  h1 X. l) h- h
    set auto? false
" B: F8 {; ?5 i, ]) q- w  [    set green-light-up? true
  W+ v. j9 \1 M+ y! b$ J7 M    set my-row -1
) C7 `' I& Y# ]    set my-column -1
3 o5 J; ^0 ^/ d+ T    set my-phase -16 Z. ?. B7 P! M
    set pcolor brown + 3
# b' O+ w, L- D9 J  ]4 U) @5 ]& j* R6 I( ^

0 E* t, F% H" E8 z4 w# u% Y  ;; initialize the global variables that hold patch agentsets; t. z: \( g) E" @4 |
  set roads patches with
# n1 e/ L6 E6 |    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
) O# A( U5 J. t3 g    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
% o2 K- r& s& X1 c3 X- i2 S  set intersections roads with: p( E! G4 F( L9 u/ {7 M- `
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and' q/ L) R/ F% u8 X. B* A
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
+ h# D" [; m6 J# @; ~% k
; L7 _# B0 A% Q" H. s: D  ask roads [ set pcolor white ]
6 j2 n% q$ {; C" z# f* a" M3 L    setup-intersections5 N. G- `6 q/ y/ g" M# U
end1 U8 x* C; k+ {/ T5 ^9 S2 E
其中定义道路的句子,如下所示,是什么意思啊?
0 J* t. n( Z2 L; _ set roads patches with6 r4 }) ]5 @+ O
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
7 w4 Y1 [( @4 n. o9 l9 ~# F* F$ w. N+ z2 O    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
$ C9 R! K; [1 [+ S& [9 r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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