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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。
$ Q& k2 `# V  b9 x  E4 K4 O6 Bnetlogo自带的social science--traffic grid这一例子当中,
3 Y  @) N' V6 A7 E5 h3 oglobals8 H; A/ R7 |) r% m/ @) [$ z/ u0 @
[2 n' H- C& ^/ `! b& n+ q
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
# Q/ f+ u4 {; o3 P+ @0 h5 n. _6 y9 I4 d  grid-y-inc               ;; the amount of patches in between two roads in the y direction
3 m3 Z+ l$ ^  T, u# x) Y  acceleration             ;; the constant that controls how much a car speeds up or slows down by if, p7 U/ {9 K) K" L+ t  v( B
                           ;; it is to accelerate or decelerate3 P) k- R1 ?9 `9 u  f. y$ E( x
  phase                    ;; keeps track of the phase* G- ~" P8 t8 F/ D) P/ b9 F" Q
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
7 f' }7 C' y4 F2 z( y0 g6 v0 E$ C  current-light            ;; the currently selected light& W& D* V# ?( E/ z8 j% G( o

, k: z& ~. _9 D: ]1 `- I* c  ;; patch agentsets
7 k  l+ t. y: @2 R- J  @! |$ [/ `1 X  intersections ;; agentset containing the patches that are intersections& K! U3 N7 D5 c0 M9 A
  roads         ;; agentset containing the patches that are roads
- m1 ?7 P; Z. X; m9 c]- b" J) _! A% _4 Y" A7 s, W
- f& }" }' c' }' I4 G5 T* s( V
turtles-own
4 j; w! `- e& f4 K/ O6 [5 V[
+ k' m0 Y8 t+ f) U% v3 ?  speed     ;; the speed of the turtle" x. _2 O5 S( l8 i. [
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right: J/ U& Z* H# H8 W* T& j/ m$ m
  wait-time ;; the amount of time since the last time a turtle has moved
0 x  z6 r4 v3 u]
: _# S0 l, k% `& i# }- D- t. q8 U* M+ G4 e% b  q( ~
patches-own
" G, c1 _6 Q9 C: I: A5 ~' p$ t, Y[, U8 E: z7 y1 A' p, Y$ ]
  intersection?   ;; true if the patch is at the intersection of two roads
( x4 Y: ~# P6 k  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.* ]1 V. Y, {4 ?. |' ]
                  ;; false for a non-intersection patches.- ?% E9 n! x( U+ [3 J5 H* W
  my-row          ;; the row of the intersection counting from the upper left corner of the
" P# e) v& c0 s" j8 T( `                  ;; world.  -1 for non-intersection patches.
- J# U7 R& @( S6 f. Q8 [- R5 j2 x2 V# i  my-column       ;; the column of the intersection counting from the upper left corner of the
1 ]$ _' w  @5 ^0 F/ T                  ;; world.  -1 for non-intersection patches.
3 l8 N8 M) C8 Q5 Q0 r' K  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
8 O6 q& Z, X) I* X8 E  auto?           ;; whether or not this intersection will switch automatically." t8 X* B( ]6 ]+ z) \6 U2 Z! v% M: t
                  ;; false for non-intersection patches.% z& H0 t6 M; v8 ]* x( G3 J
]$ b/ c' u! k( \

  T2 V. Q4 k' Z' f7 H  g) w3 m& `8 _1 u/ Y) A+ Y
;;;;;;;;;;;;;;;;;;;;;;
- U/ ~7 A' ^+ M3 J" y9 e;; Setup Procedures ;;; O$ w& |  F/ }
;;;;;;;;;;;;;;;;;;;;;;
6 w8 N* z+ @' O; a
6 I1 `% G) Y5 ~) E& G# W, ~;; Initialize the display by giving the global and patch variables initial values.
6 R: A; \) x' }5 _6 K: o3 \;; Create num-cars of turtles if there are enough road patches for one turtle to
) [9 ^+ r8 j* A4 \5 g/ s: P;; be created per road patch. Set up the plots.5 [3 ~! @" V( d- A
to setup
  ~. x$ i4 |/ w4 X8 ^7 P6 `  ca
; y, L" i/ a# T% @6 P& i; m8 s- W  setup-globals
2 q! i1 ?% x* e" `# m" C$ v+ e
" w/ P$ b1 M* D, w- }! ]+ l' q8 N  ;; First we ask the patches to draw themselves and set up a few variables, j8 n2 `5 i& R8 }' C
  setup-patches: U4 f4 W$ S# ]3 L0 ~! {! D' c
  make-current one-of intersections8 i# h7 ~' Y2 Z+ [+ v1 H! n# V" v
  label-current
/ _, H1 @& z9 |2 B. {4 v. @6 T1 D, J% {( L$ ?! P  t
  set-default-shape turtles "car"
  @9 h- l( E- z6 J1 [5 F
1 p; `$ o& k$ G" n  if (num-cars > count roads)3 K/ y6 C+ k3 F* }2 e+ C
  [
, X9 X1 L9 a; w( \" h    user-message (word "There are too many cars for the amount of "9 r9 H. P) V5 O; Q% f# T" }) v  F; h
                       "road.  Either increase the amount of roads ". j, O" d1 N9 f' a: q4 P
                       "by increasing the GRID-SIZE-X or "
8 k1 t, N4 `  x( y7 ]/ c" f8 Y                       "GRID-SIZE-Y sliders, or decrease the "4 x2 `- ]% B1 Y0 `& I4 T5 M
                       "number of cars by lowering the NUMBER slider.\n"
$ P- ?. |/ y  t) y6 z9 A                       "The setup has stopped."): h; s  y! j4 Q( X7 _1 d
    stop
, _# U# p8 V9 |) r6 T, Q0 D  ]
. ]6 V6 |- t  z4 t  H# J2 ^
7 r1 [; ~  h! ?- f  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color0 t  o) }# _6 H( W: A- \# X
  crt num-cars
( f* \% E  p$ B% x; n3 a1 N  [
6 g1 v& [2 ]  G5 W. m    setup-cars' N( S5 A( t2 t+ H. x/ q& [
    set-car-color0 a% d6 l. f0 K) }& W/ g! Q# r; O& U
    record-data/ A) Y& g! Q% O) v5 D. R
  ]1 `3 i: \( J! d/ C

! q1 X* b$ s; Q5 S& d, H  ;; give the turtles an initial speed* Z) d+ c' q7 ~2 {
  ask turtles [ set-car-speed ]
' z2 N" n, e' C0 c2 _
8 W3 x! B0 D! M' k: {  reset-ticks, l9 K6 M9 y; v+ x1 x* q; W. w9 i
end2 }  Z" L- j2 m, q
( p+ F% `- ~0 L: P% E4 r
;; Initialize the global variables to appropriate values! w4 d9 U" C& I+ X1 ?
to setup-globals, |1 ^# E7 \/ g( T( I
  set current-light nobody ;; just for now, since there are no lights yet/ \% U: l* N7 n- |
  set phase 0" U# G# j1 l! V7 \; s2 J; c% j" ~
  set num-cars-stopped 0
* E: {2 H# T+ t( C  set grid-x-inc world-width / grid-size-x
* y' ~6 R) m) {8 V0 @& V) f2 I5 l& }( n8 C  set grid-y-inc world-height / grid-size-y5 z! e* t. d0 J! u4 h
( Y$ R8 ?6 b. e6 q/ y9 |; b
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary0 n. t5 W2 @& _2 m0 Z0 k; ~8 l6 X0 ?
  set acceleration 0.099
% v3 G! K. }9 I' Xend' C# d3 |. {- M: z

( L# Y& D3 w7 I' {. ^- C;; Make the patches have appropriate colors, set up the roads and intersections agentsets,/ J. t8 ?# w; d' L$ w9 Z# \- j" J
;; and initialize the traffic lights to one setting
( s2 h6 u5 v% _/ l# Dto setup-patches- K4 D2 G8 X3 g& R9 W2 E! q5 B
  ;; initialize the patch-owned variables and color the patches to a base-color: s7 S6 F: o* t3 @1 w0 w. q
  ask patches" G; G) z2 D6 O1 C: b$ R# C
  [: F4 f: J( b6 e! @
    set intersection? false- K' u$ O. p6 Q3 j$ w
    set auto? false
% D  S) Y7 W8 U8 t& E, t    set green-light-up? true
5 z) i) \) h# T    set my-row -1
" |; {! J# u0 T2 i) U# V- |' c    set my-column -1* H. D: k1 K' i0 H
    set my-phase -1
; d+ S0 a3 F8 B    set pcolor brown + 3
. V1 B0 u0 e& D* i. C- E  ]
5 X1 ]. i0 y0 i) I) B3 c, ^  m
+ }9 ]/ ?  N1 ]  ;; initialize the global variables that hold patch agentsets  \$ L% Y3 X  ^
  set roads patches with% v# o, f- \3 @
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
; d. q' m' i  ?) w# a" Z7 D* s& S    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]' @; U; ?( b0 }$ A5 A# S0 Y
  set intersections roads with/ g9 _$ J8 \8 b
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
5 k* L7 f( M5 M( q    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
5 ?8 g  t4 ~  `, f0 Q  e# Z# M# O6 {( o7 P, n0 C" j( V1 ?
  ask roads [ set pcolor white ]
- J: I) `, |8 [    setup-intersections
8 w" H3 R# @/ R5 Kend; V8 J4 E  |) ]
其中定义道路的句子,如下所示,是什么意思啊?
5 x+ W1 A. a% P6 j- U9 Z8 C4 } set roads patches with# {$ T% K1 T( L8 s
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or# a) J1 o7 W, }' o5 s: w! u$ L7 G5 J
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
6 ?1 Y5 i" n2 X. K( M2 C/ w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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