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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。
3 [9 }5 D1 g( ?- T% l6 P$ G* M" Q* Znetlogo自带的social science--traffic grid这一例子当中,
5 T* a+ O$ ~, f. _/ u) U( \globals# l  v) ^; x7 R
[  Q/ U, R/ r/ \* ]6 E
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
5 C3 `  s8 |+ u) C& l7 d* k  grid-y-inc               ;; the amount of patches in between two roads in the y direction! ^" t1 l! ?( l) @6 O
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
3 t; [2 l+ s; r( @' J- |                           ;; it is to accelerate or decelerate
! I+ e& h" e8 A+ c0 {3 z4 x8 a0 [  phase                    ;; keeps track of the phase" B3 Y4 i0 O: I: J5 S9 T2 z! x; x9 h
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
, _5 d* j- `! J# o  current-light            ;; the currently selected light! d" I' h/ ~" }: a/ q3 @" y
' x' V( ]' T* R! E% ]2 s
  ;; patch agentsets! ^  Y7 d* e4 Y! m1 m
  intersections ;; agentset containing the patches that are intersections
8 Z7 {, m7 v+ Y: h* Z3 F8 E4 `7 C  roads         ;; agentset containing the patches that are roads
# A6 i7 V1 \7 V" k0 j- X+ M6 L]: l% M4 [2 B8 J, u7 n4 U

. m) k) J2 }3 z" j5 Qturtles-own
8 p: ~& y: Q9 f" [- @2 f1 X[; b) l+ w4 d( T' i6 S2 J& v$ }  d
  speed     ;; the speed of the turtle+ T4 j, ^, \, J1 K9 z4 y
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
# O8 b/ S6 l5 t( L! L: h+ v+ M  wait-time ;; the amount of time since the last time a turtle has moved5 `+ E: U& O5 o$ t5 D
]$ U4 @- G5 j$ K4 s+ z/ C# r

% D% [( b8 u' y' v+ a/ D! f0 M& rpatches-own
0 H, t( I8 q6 l" G8 G[4 ^4 \, U8 N# E6 }  {$ k+ G
  intersection?   ;; true if the patch is at the intersection of two roads
4 m+ |, }  C# k# m, P, }/ d  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.' B! |! J3 M8 G0 D, M0 f
                  ;; false for a non-intersection patches.
  i6 I  R. v' X0 _4 p" A( R  my-row          ;; the row of the intersection counting from the upper left corner of the
4 I/ B8 }$ h% Z6 o0 {# R                  ;; world.  -1 for non-intersection patches.0 p0 \. E* o* h7 J& G
  my-column       ;; the column of the intersection counting from the upper left corner of the
* F$ M1 e. ^% P: H! i( {: U                  ;; world.  -1 for non-intersection patches.2 O7 l5 b  g3 @
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
4 I/ T7 S+ {9 E1 q  auto?           ;; whether or not this intersection will switch automatically.
" U, n4 }6 }6 k/ m+ X/ O                  ;; false for non-intersection patches.8 G) w+ |; }# M7 \
]/ L% F/ ^" C" i6 O$ v# z
, Z( X: U4 Z4 _+ Y8 q7 m& }" K! y

% Y$ Z1 ]  x+ a& L( V) o4 t;;;;;;;;;;;;;;;;;;;;;;5 E4 p7 W$ W* ^4 ]4 H: O
;; Setup Procedures ;;
- ^+ F* y. X# N: e9 _4 f;;;;;;;;;;;;;;;;;;;;;;$ b; N4 K5 R/ ~' u& E6 g; }. D
8 I; _1 K& H, S% F2 }$ l% H
;; Initialize the display by giving the global and patch variables initial values.
7 p+ ?) |6 o, d- l;; Create num-cars of turtles if there are enough road patches for one turtle to
# F+ N) r/ u0 n3 z* h;; be created per road patch. Set up the plots.# |8 B1 Q: ]$ O+ y2 C8 P
to setup- k/ ?. _* g: A% N8 r# k
  ca1 O' G2 _. D' L: A) q8 B
  setup-globals4 Q$ t& @( W5 l4 {: r6 z

: g3 z9 T( F$ ^" R1 r  ;; First we ask the patches to draw themselves and set up a few variables1 p. M. s( L: }
  setup-patches  f- u& N; a' i* ~" t6 ~! R$ G( @% ]2 r
  make-current one-of intersections
7 Y0 J/ E  H' h  label-current" b6 n  W( w+ U8 [9 g
) l5 I0 t& I9 q
  set-default-shape turtles "car", k' F0 P+ ^& w0 N

* t1 N. \' r0 E8 ]  if (num-cars > count roads)! F* r- [4 H1 L  ^8 y% u
  [
; S- [# o% o  ~    user-message (word "There are too many cars for the amount of "3 ?2 s: g. _1 p2 l% r
                       "road.  Either increase the amount of roads "3 i) P5 V/ w3 N. Q" H0 h' n  a
                       "by increasing the GRID-SIZE-X or "
. i7 z6 Y6 w- c& t* I; @2 d( v                       "GRID-SIZE-Y sliders, or decrease the "
/ B, D" `+ a; y' O' ~4 r& z                       "number of cars by lowering the NUMBER slider.\n") s2 h# ^4 t/ Q
                       "The setup has stopped.")5 @) V& n6 w/ `  _& F; Q
    stop3 q/ i* K. V0 {9 ~9 r" t. q$ p7 L
  ]# K7 d( L: F; E1 l# f
$ p4 v6 n; x; y+ V3 V) n9 B+ G
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color' P! [1 J7 e# j- z- u' S6 W
  crt num-cars
' K" m' _9 R0 C4 [' [  \  [
5 \" z( c, ]- q6 K7 u    setup-cars
; W% d5 w2 A2 z( u! P( B    set-car-color/ z, ~6 H4 O- c* B+ |& G
    record-data
$ I0 _+ C1 h- Q4 X  ]+ F* n( x+ [6 e# @9 u

9 i  ^0 Z* E2 \6 e+ |* Y4 _2 A4 v  ;; give the turtles an initial speed
" `& x# g/ t9 E3 F: ~4 }; j, h! Y  ask turtles [ set-car-speed ]# }/ ]! j+ h' j2 K, F. ?6 H+ p

: E; c2 \8 R. j* \' W# n  reset-ticks
7 S( u6 W( ~) m0 T+ b' Cend
+ Z) Q8 T  T8 O' M; a5 r* p7 R3 W* t4 v/ j. C
;; Initialize the global variables to appropriate values
. F3 V" a+ T; U5 ]9 u7 O4 xto setup-globals
5 J$ `: E# ]% ]4 G+ s  }  set current-light nobody ;; just for now, since there are no lights yet' @0 `' S# E1 E$ r
  set phase 0
+ q1 C( D- e/ a, }8 f& w  set num-cars-stopped 06 `  L3 }9 s8 n8 f5 \6 I
  set grid-x-inc world-width / grid-size-x
5 T) v0 Q) i3 y4 [  set grid-y-inc world-height / grid-size-y3 `/ q% @1 s0 m2 l- Z  U
$ r' p1 N: H- m; Z
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
9 e8 c$ ]% J8 [( W5 z, s0 \! ?. G  set acceleration 0.099
/ \% j$ b; I- c3 P- w7 b& b$ nend( v; U# e$ A0 J# R

! r% s* E+ f+ R;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
: V9 M; \2 `) S" Z6 m% f;; and initialize the traffic lights to one setting
0 `& x+ O2 ~! [9 |& Hto setup-patches  ]% Q) H% ?8 r% l# R+ f
  ;; initialize the patch-owned variables and color the patches to a base-color
6 L, e' h! O6 R$ b  ask patches
! E/ A# x" ?- |0 v9 Z  [* L' T  a2 ^: K
    set intersection? false' u# Q3 G: _0 V7 Q
    set auto? false0 c5 Z$ i+ W' l. c
    set green-light-up? true2 p' u+ S, P) T% @! c) Y
    set my-row -1
. H+ e1 M3 |( ^% b    set my-column -14 J- b& f  \' m  R. V
    set my-phase -1( T) q( R: D* T
    set pcolor brown + 3
6 P4 L# \/ F) f8 {$ P  ]/ |5 K% Q/ b8 i5 J; }

0 Q; v7 J( ]3 G" q  ;; initialize the global variables that hold patch agentsets
( q) N" a5 m8 F$ V- c  set roads patches with
3 U( z! V$ I& A8 _: B" [    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or8 Z$ L; F$ ^' _5 u+ p% h9 M  W
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
, {  w3 o( p% \' @4 F" Z$ W5 p  set intersections roads with
! D- O$ C/ Z/ ]+ ?3 j    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
$ x6 z; n9 [; I9 P    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]) A% R6 r  m9 S* _
: M& [" t, z: Z1 y, w
  ask roads [ set pcolor white ]+ |5 Y5 s; s  d# t. W6 w
    setup-intersections4 i# v; _: B! D. J: A' m# G. {
end
( t+ P* T# f7 n& T2 B其中定义道路的句子,如下所示,是什么意思啊?6 B- o  O9 }6 a$ p6 t" R
set roads patches with
1 _8 z- Y! s* K' i    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or- n! ?/ P; q  u: S+ S
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
9 P3 c$ D# X; M% T  c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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