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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。' s; G' A( G* g7 c; w
netlogo自带的social science--traffic grid这一例子当中,! b# [, N5 Y2 z2 L
globals
1 e! \5 k! f( Z7 N4 f[# @$ J: o& h  a3 v2 `
  grid-x-inc               ;; the amount of patches in between two roads in the x direction% |9 Z5 X9 K, a0 `1 W
  grid-y-inc               ;; the amount of patches in between two roads in the y direction, Q  X0 Y' W( m! r/ E
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
' @$ g+ h9 e, L: K1 B& l! Z                           ;; it is to accelerate or decelerate3 j8 B! [/ \# G
  phase                    ;; keeps track of the phase  M* h' ?: [3 K/ {- N# x) p
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
/ t9 `2 {% n( V$ o, c  current-light            ;; the currently selected light
, w* S7 X) Z0 m2 ?" V) H
, ?. t* Y& \4 {# w  ;; patch agentsets0 s, S" r+ w) K$ ]% J7 Y
  intersections ;; agentset containing the patches that are intersections
+ E8 f/ A7 K  M# p% e& P: F& t  roads         ;; agentset containing the patches that are roads
' h. @- U+ m9 ~% {# X/ p8 I]& g' n2 u) n$ l$ Q
& p+ t; I7 Z4 V5 z& q3 |7 [
turtles-own  @' \# f7 t4 n4 h
[9 E2 c; I+ b1 u# N7 Y8 r- L( L# |
  speed     ;; the speed of the turtle
2 j( }2 c, ?+ o! a9 i  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
  B. z) E/ z5 M( v  wait-time ;; the amount of time since the last time a turtle has moved
4 t( w- _5 V3 R* \2 D]. O$ N' l$ s. f  F

2 j2 u$ M3 X4 r1 t  Epatches-own. a0 W  H- p3 K% o2 k0 S! E
[
) F4 A0 s* \% I  intersection?   ;; true if the patch is at the intersection of two roads. a/ x( `( Q- Z+ j2 b- Q+ P
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.1 B8 P4 ?/ S' W4 C8 u  E& O+ ]
                  ;; false for a non-intersection patches.# E. P& i) t- g+ V% R
  my-row          ;; the row of the intersection counting from the upper left corner of the
% u( k2 I5 h/ x4 p                  ;; world.  -1 for non-intersection patches.
6 C5 Y* ]* V% W  my-column       ;; the column of the intersection counting from the upper left corner of the6 E$ I* o# h! j. a/ ?- l# m, A
                  ;; world.  -1 for non-intersection patches.8 P8 I" Z0 T. n7 L/ j' e
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.4 @' B7 K/ |- T: @2 t
  auto?           ;; whether or not this intersection will switch automatically.
+ _4 L" k) ^$ e( y6 S$ i: H                  ;; false for non-intersection patches.
1 O5 E8 {6 O2 V( E8 o]  Z! w" s6 A( a4 m  M$ ]) W& A
, E! T, j% j* c' b; a; k4 x0 t" k
: g8 R7 s1 ]! Z" ^+ E- `8 h
;;;;;;;;;;;;;;;;;;;;;;
2 Q% t/ R4 h# r  d* u8 W3 [. U% c;; Setup Procedures ;;( ~6 d0 [; @3 p. F' L2 q# _
;;;;;;;;;;;;;;;;;;;;;;
% r, b& H; w+ x9 _9 d8 V1 v% m& D! l: |: t$ W0 f2 s2 a( e
;; Initialize the display by giving the global and patch variables initial values.9 ]. T* r! P* m- a# W0 F0 l
;; Create num-cars of turtles if there are enough road patches for one turtle to
8 f! M, g  b) n: b( x7 i;; be created per road patch. Set up the plots.$ ]/ ?1 M$ N1 k0 s( j
to setup
$ _, [8 O# }9 o5 U  {6 S. C9 `  ca
* z8 ^! [, v. E! e2 E* V  setup-globals, N2 z. y) Y& A. l2 |" f

; S$ Q# a4 b* d4 \0 \5 Z( G  ;; First we ask the patches to draw themselves and set up a few variables/ ^- I7 S! P# N2 c' V% e
  setup-patches
9 X' i! j' i; L6 m  x& O! g  make-current one-of intersections; v4 s9 t: C* p1 J1 w, q( c
  label-current
& _2 o# R! _& ~1 ^8 B# v3 Y" }/ @. y, E; ~# `' g8 l& X& Q
  set-default-shape turtles "car": e# ]7 f. d# T( L, p

9 g5 n' W) q7 {+ a+ I6 B! F2 |4 e. o5 W  if (num-cars > count roads)
5 b1 y# h$ d( b5 F: ?6 p% U! y; w  [$ i+ h/ L' v* x; c3 n
    user-message (word "There are too many cars for the amount of "& n3 E3 \) p& Z& B- N  L, M8 q
                       "road.  Either increase the amount of roads "
6 t) |% Q+ X& G7 P9 Y                       "by increasing the GRID-SIZE-X or "
3 a: A+ t1 H1 P! O, @, e                       "GRID-SIZE-Y sliders, or decrease the "
; H# j) P! X* o* N7 r6 b  F                       "number of cars by lowering the NUMBER slider.\n"
; J4 o" b; {5 C" N& l$ `                       "The setup has stopped.")
% T4 B$ c8 h! S  \    stop; \% v0 Q) [, J8 r/ U% T3 w" C
  ]
3 E# ^( c$ C: F5 s* e# Q& H! f$ J4 S8 \. F
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color" o4 k7 J& d  I4 y! h# p
  crt num-cars' |* o9 A' F% E: v1 B
  [
/ P0 U/ u# t) Z# {' w5 i: w    setup-cars
0 w$ E3 y( o8 G+ }    set-car-color  z* _1 f7 l, |9 P6 @) Z( z
    record-data# D. |6 _  V7 o8 I! H
  ]
: K6 I3 u; A7 `: J2 Y. Q: H
3 j( r5 r9 {. h# \5 A  ;; give the turtles an initial speed% A4 g. Q! i1 t+ u  l9 h
  ask turtles [ set-car-speed ]1 d3 i1 n% o6 z" A+ U

# H! Z+ \8 ]. }! D  reset-ticks' s- e3 C2 V+ E4 T  y
end8 ^; e, b* _8 q. y  r4 b

9 Y6 @' _' ?) J0 L;; Initialize the global variables to appropriate values( F% B' X) Y2 U( |
to setup-globals
) r  _( Z# X+ E  set current-light nobody ;; just for now, since there are no lights yet# Z/ J) L( z6 j) d1 Z
  set phase 01 L. k) P( O! a1 p5 v5 E. @8 C
  set num-cars-stopped 0
$ C- I4 I" Q+ ^! A/ s2 s3 R9 I  set grid-x-inc world-width / grid-size-x
0 t0 v, T1 @8 c! O, F  set grid-y-inc world-height / grid-size-y
; A# u2 r- L8 V) h% I7 Y+ x7 t% ]/ d5 X& T. `
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
7 ]5 ^( `$ k8 ]3 H  k" a8 k  set acceleration 0.099
% j# E5 W( M- _6 o. g8 r0 Cend
+ K4 O0 \3 I5 u3 }! B) |, u- ?) U2 B1 f- R6 S. r# M9 b) ?2 x
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,; L3 Z) w7 i* a: d+ h0 C& s  Z
;; and initialize the traffic lights to one setting7 I) n  Z# S$ {6 s7 A
to setup-patches
4 }9 U9 b3 G6 B' G+ j  ;; initialize the patch-owned variables and color the patches to a base-color
0 c6 x, I$ Y( |; ?; `4 ?. [  ask patches
9 c2 u. l; Q) [  t5 d/ [$ i  [
7 R: h, `, a2 [4 G& w* |    set intersection? false
  v! c$ K$ ?1 |% F5 t1 O: T6 \    set auto? false
, ~, w1 C# s% }4 I% Y    set green-light-up? true
* R- H/ c# g' Z    set my-row -13 K. o' o! W& f- g
    set my-column -1
" }4 P( B2 W) H5 e2 h    set my-phase -14 w: ~8 l/ q  P3 k
    set pcolor brown + 3
4 [9 W: y- u2 v% e+ R1 ~" ^  ]
7 ^9 V, I1 c8 A5 i# g! o* @$ H" f/ T, ]
  ;; initialize the global variables that hold patch agentsets
" f5 J( U5 t) \+ r6 _" M1 p( Y7 K  set roads patches with
1 i* x4 O+ S2 s+ E+ e3 W3 {7 q    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or/ u1 S, S3 `1 L$ O" V* A' Y6 J
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]8 {( w$ e1 G- T1 j7 K& I+ U
  set intersections roads with
0 a9 h" Q7 P" y$ B    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
/ n. c7 A8 L. ?( A5 s    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
4 |/ N5 Q3 C% @0 G7 z7 ~2 D3 ^9 X7 w/ N! J5 g& j
  ask roads [ set pcolor white ]
6 O) @8 G* D4 s$ y$ m" }$ {2 Z    setup-intersections; ?/ H: M1 w* X6 Z# c
end2 a, |/ w  f7 W4 A. ]$ f$ y
其中定义道路的句子,如下所示,是什么意思啊?
7 Y8 d7 o/ M; O" `% Z set roads patches with! l+ }2 N. s3 S1 L  W3 l
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
3 H0 y$ I: E; ]    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]# m$ D2 z: q" R* s+ e8 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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