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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。
4 |- j/ J6 [) k. bnetlogo自带的social science--traffic grid这一例子当中,
) A  E9 N7 X, X$ q2 pglobals
* A# @3 U9 n! h+ y! P$ W- w[- q  A1 @: s6 h5 Z) I& P
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
- I! v  c7 x5 n. D0 @$ x  grid-y-inc               ;; the amount of patches in between two roads in the y direction
( S/ O  a9 T1 J. u7 V  acceleration             ;; the constant that controls how much a car speeds up or slows down by if% b5 v. g# P+ g3 F# S
                           ;; it is to accelerate or decelerate
2 a2 g6 Q; t  s$ l( K  phase                    ;; keeps track of the phase
( U- s4 k# |6 o# f  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
* t8 s/ s" @& [  current-light            ;; the currently selected light
6 K) d# O# k  |' ]% ?3 u- o$ R2 J7 P/ }6 m7 |5 E
  ;; patch agentsets
- `8 ^- d" L: c9 S: P  intersections ;; agentset containing the patches that are intersections/ e" M9 A) P  H  J
  roads         ;; agentset containing the patches that are roads
" G  Y  N5 e  {+ L]
* f: u) w( u& b) J
, ]3 B) Z3 W7 I: M9 {3 Z& l0 C, u2 {turtles-own
) @: m3 X0 W& f- |' a5 k% P& J[
7 [: |* F8 i2 r  speed     ;; the speed of the turtle
' H& F" H" p8 ~4 j$ I# f  up-car?   ;; true if the turtle moves downwards and false if it moves to the right8 ^5 F, S$ p* L4 Z  `) `
  wait-time ;; the amount of time since the last time a turtle has moved
' p/ }. R; X( ^. \- z]2 E3 L+ _* {8 y. L8 N1 I
9 O; X' `( S9 T; O
patches-own
. J" N% R+ ]6 r[  ~; m7 {4 F0 Z
  intersection?   ;; true if the patch is at the intersection of two roads1 o7 j3 v9 r( E) @: p0 M' x+ k& v6 @
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
' ?; h8 I6 Z; P2 n4 ]  q: \- y; b                  ;; false for a non-intersection patches./ ]' [6 s2 u3 ]
  my-row          ;; the row of the intersection counting from the upper left corner of the
, ]* H, t/ m/ E& H                  ;; world.  -1 for non-intersection patches.9 O4 p. R& p5 A" P
  my-column       ;; the column of the intersection counting from the upper left corner of the+ |& a! I7 ~  W* _
                  ;; world.  -1 for non-intersection patches.( B0 L# ]5 o/ u
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.& ]8 y, a& }3 ?% O
  auto?           ;; whether or not this intersection will switch automatically.6 y+ _2 M9 ]& S# A! o) q
                  ;; false for non-intersection patches.7 O4 m) C9 u2 ^6 J4 ^$ h( ]
]
: T5 i# W8 [0 H5 \% X* I( F" }" v+ J) d% H9 w" k  K& N  o: `
+ {9 w; w5 h; H7 g! _
;;;;;;;;;;;;;;;;;;;;;;0 j) M; [$ s) G
;; Setup Procedures ;;
6 q: a0 j( X+ Y1 I5 g/ l' o( g/ `;;;;;;;;;;;;;;;;;;;;;;
5 S$ b5 A0 g- G7 m! N; `& V. P
9 A% Z: T3 {+ t! \. r  d;; Initialize the display by giving the global and patch variables initial values.
3 G+ g. Z) m0 q5 L9 s  G) g;; Create num-cars of turtles if there are enough road patches for one turtle to3 n( S5 V: U) F! ?% L4 m. s2 `9 Z2 I
;; be created per road patch. Set up the plots.1 @, s0 f, \( J# A0 \( i; i
to setup; o( Q# ~8 k) ^0 R# q
  ca( ]; z) Q( l9 m# V
  setup-globals
" K' M7 l5 d% q: i/ n. l5 S" k+ u& W5 j5 y+ E9 y5 s: I
  ;; First we ask the patches to draw themselves and set up a few variables
. T6 Z- c' a5 H& L: Q* X6 @: H  setup-patches3 K- }! i8 v/ Y, b1 l) j
  make-current one-of intersections0 p& A- c' b, ?: e1 T6 T  T
  label-current
3 i- F) h2 J5 O8 r( [
# z6 l* a4 J' h8 x$ U8 M  set-default-shape turtles "car"2 l4 ~- P4 S) g3 {- R

9 O- L1 L/ \; g  if (num-cars > count roads)
* H3 Y& o: k$ V  [
+ P8 Y4 `7 A7 z1 \! P4 }5 O    user-message (word "There are too many cars for the amount of "  D2 W$ X  _2 m& c
                       "road.  Either increase the amount of roads "
! D7 d$ ~- i3 m/ Y* x                       "by increasing the GRID-SIZE-X or "
; @( T7 {. t' X" K6 f" H                       "GRID-SIZE-Y sliders, or decrease the "
2 V. y8 S+ \  k2 w2 I                       "number of cars by lowering the NUMBER slider.\n"
9 Y0 d  @9 g/ `; J' `                       "The setup has stopped.")/ J, R( {2 i, [6 x* T
    stop% m" m5 ~5 ]* l( b$ z
  ]
3 i/ f4 `) ^) D$ |$ C/ ]
+ S& G6 ~- }* H; n% d3 a; T  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color- I, X1 Y3 \4 Z2 x" _3 ?! R8 f
  crt num-cars+ N: |9 D6 j; ]4 w) q/ P
  [
# _& m4 D2 k8 w  _" {) Z( \    setup-cars
0 o/ X2 @/ F4 q. g0 P; q! i    set-car-color7 b/ \: X- m, Y7 g: p+ u
    record-data* z- L5 C4 p+ A  P
  ]
. t5 l% G4 \& _% i3 U1 y' q+ T
& R2 Y1 R1 O/ H  ;; give the turtles an initial speed
" A. X4 N% Q1 n/ P, ~  J' _: S1 t  ask turtles [ set-car-speed ]
/ |9 f$ k; A9 [8 c. {9 M* L6 t* i: \1 G7 Z, V6 e
  reset-ticks* f0 z! k6 k2 h5 N; p' p: ~3 O  W, R
end- O- _7 M& p( L+ n: h
: g. Y5 D. [( J9 ^+ @0 s2 P
;; Initialize the global variables to appropriate values8 |& L( _( J: p( S! Z$ m- z
to setup-globals
* z& e% }# [! ?. r* w; ~. C  set current-light nobody ;; just for now, since there are no lights yet
, p; e, [. ?2 X7 p  a- K0 l  set phase 09 u: C. [& n, I- S3 H$ w( Y* \
  set num-cars-stopped 0
! G* w# a/ l' f+ j: W  set grid-x-inc world-width / grid-size-x
- z/ a7 [' o! v- I& N  set grid-y-inc world-height / grid-size-y& P: G! v# }5 Z( `

. y& b/ A+ c2 f4 C* @  ^( n  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
; S8 M4 M: D6 `5 p* B1 H9 c  set acceleration 0.099
0 O9 _2 ?: ?5 vend
, J; B/ _8 \0 r& `" q; n6 `( @; }" ^7 u/ ?' w
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
3 o- z, J! j9 @; _2 J/ d+ P;; and initialize the traffic lights to one setting/ B( h- i2 Y; c7 y5 U0 r
to setup-patches
) O5 v6 N8 P( z& H  ;; initialize the patch-owned variables and color the patches to a base-color
: d- ~; w) J: C" E' X  ask patches) r5 n. b  h. G1 ~
  [& Z, p% \0 z4 \
    set intersection? false
" W9 a+ C% W( P  J: V    set auto? false( s) p: q7 J) O. u. O
    set green-light-up? true" Z( f5 K0 M# r) m: c. m" M
    set my-row -13 f% x5 \& j3 P5 O* X
    set my-column -1. G  |9 y0 I, H: Z8 `2 `
    set my-phase -1
+ e" Z# b1 s, S6 v7 l; w    set pcolor brown + 3
! s) z7 Y% p4 W: y  ]
' A& Q2 I" x- \% L4 g
) F( [! C8 B- ?" n" y7 k) `  ;; initialize the global variables that hold patch agentsets
, _' B. d( s+ O( x$ z  [5 l  set roads patches with
9 i* [3 i( h: E- i4 Y$ J1 T5 B9 T    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
8 u/ l. {- x2 J. m- {0 B# e, E4 a* [    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]# Z1 P( i8 i9 w# E9 V/ C( p
  set intersections roads with
( M" M/ D) U( Y* g    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and/ j% ^* C6 x" W! Q9 {: h
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]! {3 v: d% T  s( Y% S6 U0 c
& r, L+ {+ i: a; n! f
  ask roads [ set pcolor white ]0 A2 ]( Y* Q1 c
    setup-intersections, h( Q& O+ Z/ Y: y7 R3 Z
end& N0 P0 I" g' {( W5 j6 G9 R8 n
其中定义道路的句子,如下所示,是什么意思啊?8 i2 m* {: @2 A( ?! c/ ?7 `+ ]% t
set roads patches with) W" k# y& p) d! ^9 ]5 q
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
4 w2 K* h6 k& c8 {+ ]/ v    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]5 S; e6 F; Q$ T  M' n
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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