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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。  `6 P" j3 A' N0 k
netlogo自带的social science--traffic grid这一例子当中,9 T5 F! R, x7 k
globals  O1 N) N' ~& X
[
* l: q  X) X9 p$ o/ C: Q5 P  grid-x-inc               ;; the amount of patches in between two roads in the x direction
& y! G/ H3 N: d7 Q( y- P  grid-y-inc               ;; the amount of patches in between two roads in the y direction
' p/ j6 r" S9 A1 k  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
0 K3 j) ^/ z  r* ?4 ~7 J                           ;; it is to accelerate or decelerate
3 f4 I' O& y1 \' e3 |# _  phase                    ;; keeps track of the phase
! E9 l) V5 ]3 d9 }8 f, F" \  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
3 j5 }4 A5 P# D2 c! [* u0 N9 z  current-light            ;; the currently selected light* P9 y+ `4 b2 A* |9 Z; ]) b* F$ X! q, S
$ A7 @4 m# b7 N0 K0 u
  ;; patch agentsets
- w( {& W! P% n9 Q  intersections ;; agentset containing the patches that are intersections
! R5 h# q' B) \2 p  roads         ;; agentset containing the patches that are roads/ g3 u4 e/ ]' X% I2 i
]- P5 o" j7 [: F  ?2 H1 t

9 }( u: S$ z+ u& S0 `$ bturtles-own
& L* K/ ^# B3 `  ]4 F$ Y  [[0 H- V1 w" I% I3 F
  speed     ;; the speed of the turtle
! `) x  U5 r- B+ c( ?3 H  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
$ C: v  O$ B! {2 ?& H  wait-time ;; the amount of time since the last time a turtle has moved. s7 [4 a9 m& v3 t
]8 [) C" K3 k3 m" ]
& `1 g# E$ P7 c: l
patches-own9 H5 \, D, K- t. o
[
% v, u8 _8 K& z$ j9 D+ K7 X  intersection?   ;; true if the patch is at the intersection of two roads2 i0 P0 g! o+ |0 |& H; |: I
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
0 W+ ^! R6 _% w5 H( g3 J4 k+ K                  ;; false for a non-intersection patches." `' d9 [' i" ]7 }: g& f7 w
  my-row          ;; the row of the intersection counting from the upper left corner of the1 I4 b' w- Q0 e2 \2 z, T
                  ;; world.  -1 for non-intersection patches.
# t: B! |% _2 B" ], v  J. l  my-column       ;; the column of the intersection counting from the upper left corner of the
/ z$ d- f* F9 e9 h                  ;; world.  -1 for non-intersection patches.* y. P: ?8 n/ A% I4 r
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
" ?4 b: @6 d3 ~- B, T  auto?           ;; whether or not this intersection will switch automatically.4 r! h; |# ]9 E) c7 _" c9 w% S
                  ;; false for non-intersection patches.0 w- K( |& d2 L% k( ]
]9 d; A; y5 Q" E" m' C  U! W

2 L( n9 N, {* J' K; c, Y0 o% \7 ]6 S3 t; V6 v4 w& Q, t7 l/ ]
;;;;;;;;;;;;;;;;;;;;;;
0 Z4 ~- |* F9 W" O8 M0 q: k' }" g;; Setup Procedures ;;
: H" q+ ]4 @$ a, j5 P- q& r;;;;;;;;;;;;;;;;;;;;;;8 B4 D$ Y1 X) O
: f$ o$ P  q5 g6 Y8 e
;; Initialize the display by giving the global and patch variables initial values.- H( W/ `; I2 T
;; Create num-cars of turtles if there are enough road patches for one turtle to
8 I8 P  I2 \# l/ k% J, K;; be created per road patch. Set up the plots.& [  ?+ p; E2 k4 O% g1 U
to setup- N0 |7 u' X0 n6 H) p1 B- p
  ca
: {' m. C# v3 @% m! _6 I  setup-globals
0 W$ k" O. e; u% p6 K2 G
+ j5 j, M8 T9 C6 n6 D+ b$ j  ;; First we ask the patches to draw themselves and set up a few variables+ ]3 I  B( |% r, o" ^
  setup-patches
3 p  R1 E; q- [* S" S  make-current one-of intersections
3 v5 f" P+ y3 q1 K. |5 p" m6 M  label-current
1 n6 s5 Z# N6 J7 y
3 {  J5 x- `- A; k% i  set-default-shape turtles "car"6 x7 y- k" N7 |1 m* S0 T

6 b. @7 g3 g4 {, Q  if (num-cars > count roads)
! o; R$ n! s. J3 b  [' A! m" P7 _# i6 j) k- y7 m
    user-message (word "There are too many cars for the amount of "; {  h/ g/ v4 f
                       "road.  Either increase the amount of roads "
  k/ D* |+ e8 O" d                       "by increasing the GRID-SIZE-X or "
8 C4 C, ^% p4 J" q) t. j                       "GRID-SIZE-Y sliders, or decrease the "; q/ T. G& R, U0 o" N) q) T' K
                       "number of cars by lowering the NUMBER slider.\n") X) e* b; h; `
                       "The setup has stopped.")1 D' R' _( u0 d: _+ m+ q& _% ~
    stop# ~% _% H) T, G& j0 i( Y
  ]( J/ R0 S! H- o) f

! {9 u# ]1 b; s2 ?* W  x) Z  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color+ n* s9 \; F( \% J/ `! \5 ?
  crt num-cars; \& Y% P4 n- z7 _& |/ K9 g
  [
  `. v/ Q/ u& L5 m! G& i' W- ^    setup-cars, \5 G* t0 z! C2 T
    set-car-color
5 _7 H1 d& N( m0 W9 j    record-data. N5 Z" b6 r* R" h1 c4 ~2 X+ ~& L
  ]
, i( d' o* @/ M2 m0 ~& J: P# O/ K! e2 u2 I- ]* Z1 b. \* {
  ;; give the turtles an initial speed. j- L: l& u; ~  D- `" n
  ask turtles [ set-car-speed ]
2 w" }3 e. W& h# v8 Q) W, M1 ?
) j- H7 f$ t. E5 z4 k+ J  reset-ticks. z4 G: j6 u; m$ z; K  U- M& A
end
5 Q* a" r& j/ h9 B% j. n! ]$ _/ v3 E$ W0 N0 K3 Q2 o! K& H/ C/ @' b4 o) M
;; Initialize the global variables to appropriate values8 t' L' a4 m$ b: M. V* b: [/ A
to setup-globals/ V# f8 s3 L* W. H6 c$ E: J' W4 Y
  set current-light nobody ;; just for now, since there are no lights yet  S" C6 f3 P( H; x- k5 A0 o- l
  set phase 0
0 x. C4 X5 k- Y( Z" f4 ~( B) R  set num-cars-stopped 0
; K9 ]! ]* u/ z! v) [  set grid-x-inc world-width / grid-size-x' C# H4 [! G3 }; s  d) D
  set grid-y-inc world-height / grid-size-y; \- p4 H/ \4 C/ }4 ]; _

# B' k  G+ [0 U) s0 h" X$ w( W  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
/ ]$ I* a0 M1 P9 |' l  set acceleration 0.099
" z" e2 K1 K- O& [% iend
( S3 b9 ]( m1 E; y+ @! b; F
0 [% W  `. |7 j" w' j! P2 ];; Make the patches have appropriate colors, set up the roads and intersections agentsets,- G2 i" J' F% V# V
;; and initialize the traffic lights to one setting
3 u) A& ?! B! G* Ito setup-patches& j! ^0 k- `6 n2 l' n& |7 l- g
  ;; initialize the patch-owned variables and color the patches to a base-color
1 R6 {/ S0 e+ K  Z# W  ask patches0 D5 C7 M& n0 u  d& C8 p0 v4 F
  [0 T8 e. V( @  d  X& U3 S
    set intersection? false
+ R5 s/ \4 h  `; Y    set auto? false6 y+ m8 v1 m5 z1 A
    set green-light-up? true
( }% a$ n9 ?: z, V4 B% x! g    set my-row -1' K' }8 s- e- g2 a% j: @- k( I% ]
    set my-column -1$ ^6 m* h' S1 w, I2 k
    set my-phase -1
0 {0 A# z6 b' }* ~" E7 _$ S" [    set pcolor brown + 3
, H( }, q/ L& [  o  ], A- h9 P; c+ U% H+ ?

2 m6 o# R8 Q' r* {  ;; initialize the global variables that hold patch agentsets
- b& Y+ }/ w+ ]2 m# a7 {- Y: K  set roads patches with1 G4 o0 J/ U: S6 g
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or) K0 q# D5 W- W( o
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]' _. G: S! n: K
  set intersections roads with) C$ P3 d  k3 P; {0 C
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and% Z: a4 `9 a7 R2 [  B1 _& q
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
" t6 K/ C! t  Z" e) u" N) ]0 h* p! q8 a: j
  ask roads [ set pcolor white ], y- N8 c7 ~, C$ ~7 f' I
    setup-intersections3 w; v2 e) F7 c! P0 Q2 O3 x
end5 ^& g5 ^6 A5 Y1 t5 Y0 o; f% B
其中定义道路的句子,如下所示,是什么意思啊?6 {2 u. o+ r+ G
set roads patches with0 y7 Q: A/ X  R; ^; N! `1 M
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
  H9 B! W: b3 z- E+ C    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]( g: t% G4 \, M+ k5 ^% 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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