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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。
& U/ ^3 t, m+ N0 j+ Z0 Z4 ~% m# N5 Bnetlogo自带的social science--traffic grid这一例子当中,2 g' O: _( y* u7 r4 r7 n; }
globals4 W4 t8 j$ g" F7 G3 |' f; D' N
[
2 @) g. s- X: g1 B  grid-x-inc               ;; the amount of patches in between two roads in the x direction$ L3 t: B9 G* Y; P
  grid-y-inc               ;; the amount of patches in between two roads in the y direction
& E8 T- v5 |; b6 I& p1 x  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
/ U$ Q. K4 x7 c/ A* t                           ;; it is to accelerate or decelerate* p' S5 Z2 _+ P1 [
  phase                    ;; keeps track of the phase
5 ]$ J1 n4 q4 A+ v, j% m* O  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
3 c: H. \/ |* t  @1 l  current-light            ;; the currently selected light) q8 ?$ ?. V( K2 r  _% k

+ a0 r4 H0 @  V" N0 j( ^6 s+ [/ `/ s  ;; patch agentsets
$ |9 X. W5 t. l; S3 \, K  intersections ;; agentset containing the patches that are intersections. q. ~2 u( X0 t# E" ?7 ^# }: H
  roads         ;; agentset containing the patches that are roads% }! o$ C0 _0 Y9 c
]/ H1 i: k1 T6 Q- l& U6 ^
6 X! M7 p1 [+ @, ~+ I4 c
turtles-own
6 o4 V) u- m+ t& m' n6 k3 X" [; s[4 z: @/ j  R' V4 N  u/ l
  speed     ;; the speed of the turtle
* i0 ^( n8 Q2 H  ?7 b9 p  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
) d6 W. u; }: i  wait-time ;; the amount of time since the last time a turtle has moved2 r5 d/ S8 F4 c
]
$ q* i" ^8 U: X/ H. x
: L- P/ M' L: f% n# a# C  Bpatches-own6 f+ e. ^' _) }! \. [! W. m
[- ]2 S: z3 O& d9 h* i9 b
  intersection?   ;; true if the patch is at the intersection of two roads
8 x4 [3 i2 ]# D$ a! Y  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
) l; {" m  \9 R6 c                  ;; false for a non-intersection patches.$ J7 R9 q4 v$ y- @
  my-row          ;; the row of the intersection counting from the upper left corner of the. @+ v: G2 [3 f, O8 ~9 P
                  ;; world.  -1 for non-intersection patches.- r# P) p; u8 f# y6 ]: w7 V
  my-column       ;; the column of the intersection counting from the upper left corner of the! F- c$ E8 J$ o( E6 q
                  ;; world.  -1 for non-intersection patches." _7 W" `0 O% @4 M: D
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
9 j1 c4 _" A* w" y/ A1 `  auto?           ;; whether or not this intersection will switch automatically.2 k' I" c+ }1 @5 x! Y) f: }- ~
                  ;; false for non-intersection patches.
1 x$ G  d* B3 k# ?: X5 a* i]! a  G, P: m  J9 h0 A( w$ Q

% G- e, N7 \, W# N$ w/ C/ O- j" g; Q8 D
;;;;;;;;;;;;;;;;;;;;;;
+ S. {) b/ ]/ c6 Q5 t;; Setup Procedures ;;6 a% E' T3 c# I, A: h0 h
;;;;;;;;;;;;;;;;;;;;;;! V5 o# j( _7 `" ?+ M5 Q0 Q% H2 X

. a1 c3 [9 T1 o# L;; Initialize the display by giving the global and patch variables initial values.  a) Y% h" M  ~  R0 @
;; Create num-cars of turtles if there are enough road patches for one turtle to
) g9 K" @+ [# w2 G+ G$ u;; be created per road patch. Set up the plots.
) j! o/ p4 l8 [to setup
! g0 c" `( a0 T: l2 O" Q  ca' Q% s. B3 j8 T+ W
  setup-globals3 y2 A- y" w! E( V) X
, I$ R  z' q( N( a7 r
  ;; First we ask the patches to draw themselves and set up a few variables
# E* R, p2 D8 J' ~  setup-patches
/ ^' L  _/ `$ B. Y  make-current one-of intersections
2 d' ^$ D* j, C8 B- M2 s  V7 N4 y  label-current! C. @$ D9 D3 o7 M

8 z+ y4 i4 V- t  set-default-shape turtles "car"
# k4 @" l: K5 T
- n% x- c; W; R  j& b! F( L  if (num-cars > count roads)
3 [+ l4 L0 d- W( ?- T  [
4 `2 b+ b5 Y% k& H2 y) H. |    user-message (word "There are too many cars for the amount of "
' [( F8 ~6 h; w+ F                       "road.  Either increase the amount of roads ", I+ a( f- b; @( a
                       "by increasing the GRID-SIZE-X or "$ s; k6 u% B8 z4 a
                       "GRID-SIZE-Y sliders, or decrease the "
6 m/ C1 k0 C/ m9 R                       "number of cars by lowering the NUMBER slider.\n"7 |; y1 H7 ?. t4 R7 Y" C4 q4 P
                       "The setup has stopped.")/ y' ]9 R+ j+ w0 p8 [
    stop2 ^# ?  J1 d$ }5 K! M! X: L, R# m
  ]# H/ N: d6 C2 |1 e# n! s6 S( z4 _

& X' Z' b8 C/ t# @' I& E: s  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color4 H7 y% _7 A; U8 x, ?5 u
  crt num-cars
4 x$ N9 v" E6 `/ \+ l2 s/ X  [
" d; g- s: O; P. d* F0 ?/ y0 U    setup-cars
1 n& _+ u7 x6 T: s6 C& U    set-car-color1 ]9 A6 v* d% t: A  L: X5 n5 A5 w6 ?
    record-data6 z* A' M$ ?5 Z5 t
  ]9 G9 p% `3 ?/ w( D- v: h
# P3 Z$ p& V- q4 Y
  ;; give the turtles an initial speed
6 g8 q* w& u8 q0 Z- F4 Z  ask turtles [ set-car-speed ]
. W! p2 \' ?' p. F
4 ]7 ^7 G+ r) C; i0 U) {% N  reset-ticks$ @, V' j3 c2 i- a' \  z8 F
end
  {7 t0 t0 Z, x6 j- Z
, ^2 G6 k- |4 T2 q8 {;; Initialize the global variables to appropriate values0 b+ x: v2 {& _% N
to setup-globals
- w5 N% g- E% ^5 F/ N1 I, a  set current-light nobody ;; just for now, since there are no lights yet
" p' Y9 p0 \3 C0 n1 ^7 N$ e( G6 b/ f  set phase 02 @' M1 j  o6 M- H" N, @, x
  set num-cars-stopped 05 O8 g7 ~, m' I0 E5 K' T0 ]" k
  set grid-x-inc world-width / grid-size-x" W, {. D* ~' j' ^
  set grid-y-inc world-height / grid-size-y; @9 ~! U/ M3 [! m' v& U

6 P2 |- _4 z4 Q  B5 _" w1 [  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
2 T1 }0 J% A- e1 T3 O0 p$ t- Q* @  set acceleration 0.099& U: l& s/ ~2 v# u/ ~# O9 Y
end
" S" F" B9 \3 H/ D$ {
7 Z1 V1 g% V8 l# L3 z+ Y;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
9 l9 u! A9 V. D# v- b; };; and initialize the traffic lights to one setting, k6 X! F" F$ a
to setup-patches: L2 m2 A# b/ S
  ;; initialize the patch-owned variables and color the patches to a base-color+ y9 o1 W2 a) N; s- a
  ask patches
7 L8 X/ B4 ]. ^* L& J; v( T: p; R( U  [
0 J7 U7 Z1 x# r; i' \9 O! d    set intersection? false" [# D' ]/ Q( g! c& a( d
    set auto? false
" @' l1 ]. I7 R2 M  o    set green-light-up? true! P6 _$ P# a; R0 M
    set my-row -1
/ R% B, B" h" Y! b4 k$ L( `, v    set my-column -1
# _( Q, Q+ s  t+ |2 x! p    set my-phase -1' Z. h6 B" B$ s: v, t/ h) J
    set pcolor brown + 3
3 }8 o" `3 k; [  ]
8 d* H7 `$ b$ J& S' M. O' z
  `2 i; q, X/ |* ]2 y% k, D7 R  ;; initialize the global variables that hold patch agentsets
0 T+ R5 ]7 s' L1 p  set roads patches with
; p, t  |. Z3 K" \7 o# X    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or9 t, m# s) H8 C' t6 s. p; ]
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]9 I5 V1 f- u: B, ?8 ^
  set intersections roads with
4 E9 }/ d8 y' F( m4 ]    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
& e! |' d3 E. a$ r. I. Y    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]" h6 ]9 m7 T+ ~, O6 q% q9 ^3 I
+ I, j4 l8 O+ w. P  M( D
  ask roads [ set pcolor white ]
$ H3 A# `) v* i0 J2 u% h6 D2 _* ?    setup-intersections0 ?( g' A' [; e2 j+ M; u* m2 t# y6 ?
end& F1 ~( ]6 D  J6 Z5 {) M
其中定义道路的句子,如下所示,是什么意思啊?" `% |( a( l7 i& ~) Y4 }, A
set roads patches with
( O: C  `9 I1 O1 u    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
  o4 J" a  @: u; e    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]' r; v  Z: K7 H; y
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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