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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。
" ]9 }) S8 [% y# S/ W) N# Bnetlogo自带的social science--traffic grid这一例子当中,/ ~. V) \5 U% i4 @# S/ ^5 a- }
globals8 B; s6 Y/ B0 [
[; k* j2 e0 C. b* I
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
! K) S3 o, F, D. {  grid-y-inc               ;; the amount of patches in between two roads in the y direction3 J3 G4 \1 U( ]* T+ @
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
: e2 R( p) g: H- X                           ;; it is to accelerate or decelerate
8 A5 A$ N  Z! @. ^: Y  phase                    ;; keeps track of the phase
: T+ h4 G" c' {  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure. e7 f4 ^7 ^8 i0 }5 G" L/ P
  current-light            ;; the currently selected light1 P6 S- a7 v, h8 C$ i3 d
9 G- O1 l' T! |
  ;; patch agentsets' l! ]7 H! r& Q2 G* |! P' E4 _, D% H) K
  intersections ;; agentset containing the patches that are intersections
9 I1 D: \9 H8 U2 E  roads         ;; agentset containing the patches that are roads. G  \" B# p+ q: X  i
]1 c' ~' ^4 N( V; H4 z) l6 I8 {
+ ?4 }% _- E( a# {
turtles-own
1 u" _, D' q5 v0 E[
* e/ }9 n6 `. m! l/ D* Q' Q  speed     ;; the speed of the turtle
- F2 ]9 x/ S# n# ?$ |7 _3 i! V  up-car?   ;; true if the turtle moves downwards and false if it moves to the right: h, l& b6 w. z
  wait-time ;; the amount of time since the last time a turtle has moved& s+ |/ J! q5 [" j- W, L* z
]
* ]& k  A7 H' E4 [8 q0 G: P# g- f* A5 U( i9 n3 @
patches-own
2 ?1 \6 a1 W& f& S& ^7 f[% A! p+ H8 a6 r( o
  intersection?   ;; true if the patch is at the intersection of two roads
  v: G1 J$ n7 s5 @5 ]# }$ }- J& i  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
: x! [8 X" q6 [" P                  ;; false for a non-intersection patches.* s! H+ p: m# e4 g) a! O+ y
  my-row          ;; the row of the intersection counting from the upper left corner of the
( J9 b! {5 x' n& ]' q: E                  ;; world.  -1 for non-intersection patches.3 B/ R  _" [0 k; W& l
  my-column       ;; the column of the intersection counting from the upper left corner of the& d0 p  v3 d5 Y0 a& U* I6 I2 r# `! B) k
                  ;; world.  -1 for non-intersection patches.
3 I2 ?$ X4 G! T& w: H9 H- f: ^  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.6 y, [9 L, U. J/ c/ {
  auto?           ;; whether or not this intersection will switch automatically.$ c5 ?3 Z; V7 e) P1 ?+ F9 e
                  ;; false for non-intersection patches.
1 N% q% n  `6 N) C]
; R4 ?( `+ {$ B4 r4 S) n( A+ @4 L/ W, Q. P3 W
$ ~2 b) I2 P" M8 b4 C7 T
;;;;;;;;;;;;;;;;;;;;;;
. P+ _8 J9 x8 M; b  G0 f;; Setup Procedures ;;' @: J! R* |! I" z
;;;;;;;;;;;;;;;;;;;;;;
2 c9 ?; L, S3 I. H0 B2 k, Z
' U, F! T! {9 _9 a  U) S;; Initialize the display by giving the global and patch variables initial values.. X! p- P4 i2 b* I
;; Create num-cars of turtles if there are enough road patches for one turtle to, F; y. [) C+ X. @5 R2 Y% j  Y
;; be created per road patch. Set up the plots.
" {0 t* q" q! z  [& b% nto setup: ]7 Y9 q. C8 l* y7 Z, u3 x$ l& D. _
  ca! q4 N1 k' e% L3 a3 _
  setup-globals
: |+ J: s6 @0 ^" }; v* E  L
1 g% l5 ?0 E$ K4 M( f! t: ~& b  ;; First we ask the patches to draw themselves and set up a few variables
! L/ R* N7 F4 r% c0 d+ x" x: b  setup-patches
' E5 {. p/ ]: _% U  make-current one-of intersections# H2 ]3 \% b1 C9 G$ D+ X
  label-current7 q' a) w1 [2 X$ U" k

& C/ Y5 M. e$ z  set-default-shape turtles "car"
6 r; [5 }/ \+ v* W% z8 T" W/ e. a: I- U( ?0 M- E1 ^, w
  if (num-cars > count roads)
+ W* g6 O/ i" }$ w( y- f  [
. `, G' v3 s$ o- o    user-message (word "There are too many cars for the amount of "9 _+ P8 s' [" w
                       "road.  Either increase the amount of roads "
; O7 j7 |# J' h                       "by increasing the GRID-SIZE-X or "
0 c' |5 F3 K% n; X  a) j                       "GRID-SIZE-Y sliders, or decrease the "
) T8 u- l: y. l4 n9 ^  \9 A8 d                       "number of cars by lowering the NUMBER slider.\n"
6 E. g; M, i8 E. T, W                       "The setup has stopped."). U/ q  `# _, |* j/ u4 q
    stop
. d) c9 n0 V, ^9 S3 R6 N7 S  ]
! Y* ?- e4 @! |: d' R" |$ ]5 H2 J$ q6 c  R+ V; x
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color1 F& O; Z4 C: A) @* L5 R7 H- T2 e
  crt num-cars
% W: Z6 C4 i0 K  [
) n; a  Q1 F! i    setup-cars
* e2 l" g+ b7 T    set-car-color
' Z0 @! o; r) y1 R: @# a/ a8 }0 q    record-data* T+ C/ M+ w  q6 Q* s
  ]  W+ G1 Z  \/ {- p
; M( c( n3 Y! a  {/ v$ i
  ;; give the turtles an initial speed$ T) Y) L7 }# N& F4 r7 Z: Z
  ask turtles [ set-car-speed ]
4 e/ j# I; W( j! h7 U3 K
" p9 M# r: Q: K7 S* z  reset-ticks
. B$ M' n  ^2 `5 D& N# d! Mend
- e% a' V* U+ r, R8 B2 Z
8 U' {3 n; P4 H% Q;; Initialize the global variables to appropriate values" _/ x) `! V" H
to setup-globals
" @, S2 `, l/ J  set current-light nobody ;; just for now, since there are no lights yet% W4 }% p# E# Q
  set phase 01 j1 t2 H8 x1 y
  set num-cars-stopped 0
- r2 p  f/ m2 L: G' @* l  set grid-x-inc world-width / grid-size-x
2 Y( A  |. T9 e  set grid-y-inc world-height / grid-size-y
% {4 @9 h5 M  V% s# @$ t" l: |0 ]  |8 C& U  V
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
: G$ t) T6 a2 l+ O) m. f; [2 x* T# s  set acceleration 0.099
0 p5 T7 A- x9 n% b$ Y6 P$ {3 Yend
5 U# {' c1 t. p& z# a/ F  a7 L; U6 E9 ?8 d
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
. u7 X! z- f0 l4 h2 R;; and initialize the traffic lights to one setting
' f4 k: K% x* Eto setup-patches
( C3 R- x. h) d) ~  ;; initialize the patch-owned variables and color the patches to a base-color
4 n; g" ?/ `% j! E# w2 i  ask patches
1 j% O6 G" _( N% O  [
: a9 f7 F4 P, p9 s: j  a4 v    set intersection? false
5 z2 W5 e1 K1 K    set auto? false
; D6 W: T5 h9 }    set green-light-up? true# s2 V6 [1 H% h# A/ k3 z% ~
    set my-row -1, q2 u7 ^8 a( A9 g7 j1 W
    set my-column -1# d; i7 t  c, B  V) R
    set my-phase -11 M, U! Z( `. p* p  n3 {" f
    set pcolor brown + 3
' p! l. X+ \, v; H  ]5 c9 }8 O$ p) v" @7 J8 j1 n( h
/ }% E; j$ T/ E0 d
  ;; initialize the global variables that hold patch agentsets$ o" B& P' p- E5 O+ ?4 i
  set roads patches with
! A& o' u$ F0 P# ~( g    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
9 F# |' S4 w1 ~9 [) h2 y    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
: n' t2 m$ Z6 k  set intersections roads with
9 o6 ]8 _5 n. |: z4 c    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and; N- I. v: P) ~2 T& v
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
- j% y  W4 A# s8 g; g* B8 \9 N: {( f" v' N+ U
  ask roads [ set pcolor white ]- n9 r9 W8 g  l+ o3 Q+ m
    setup-intersections
2 b1 G9 R8 W5 x9 A7 I: Wend5 L# P# F( z. x! Z1 o5 `
其中定义道路的句子,如下所示,是什么意思啊?. z  ~4 j' Z0 C3 n
set roads patches with- k, L* q" h0 V# P/ l
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
& E: c$ g, |# G    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]0 ?6 U9 D  D6 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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