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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。
1 A+ ]. V8 g1 m* rnetlogo自带的social science--traffic grid这一例子当中,( n9 Z) M( Q' p% h: ^: t9 P) P! T
globals4 Z0 ]# w8 p# M, E
[2 b- {4 D+ r/ L0 N
  grid-x-inc               ;; the amount of patches in between two roads in the x direction0 k% @& }1 H8 U# K8 s/ n
  grid-y-inc               ;; the amount of patches in between two roads in the y direction
0 K8 a9 L: Z. S8 Y. G  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
- J! g) u) J8 t+ k; G. k                           ;; it is to accelerate or decelerate
! @0 H3 P% m' O1 j/ G0 }7 F  phase                    ;; keeps track of the phase
$ ]# V: `# R7 E8 b: L! N  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
; N6 H/ Q) p: K2 M$ v( B  current-light            ;; the currently selected light1 E+ U2 p; J+ S. S6 {2 k- z
" X, P6 d: R" @+ {
  ;; patch agentsets
8 A* B; v. o& g! p; W, P3 O  intersections ;; agentset containing the patches that are intersections" q$ W: _4 |# j$ Q+ f( ]
  roads         ;; agentset containing the patches that are roads0 B1 |* P5 \  X' c
]
, W2 ?# U0 M3 M8 S2 C- d: N; l9 J
turtles-own3 y6 y. H% q- r0 H$ ]( T% Z. v. {
[
8 @# O1 o+ }# u8 J  speed     ;; the speed of the turtle$ @" g- i  W' v7 @* D4 P: K2 S3 @
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
8 }0 X# x' t% z0 ^! ?8 X  wait-time ;; the amount of time since the last time a turtle has moved
- {1 Y/ W! \' F7 H0 S# {3 |* @& H]+ ~$ N$ B" {9 m, v/ L8 g

: \% h3 m& D# Z1 g4 Ppatches-own! z1 ^4 H/ u+ K' n  W9 i
[5 [$ n7 D! l& R9 @/ ?
  intersection?   ;; true if the patch is at the intersection of two roads+ p4 _/ C- g! n/ t1 E+ i
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false./ @# O) E6 g7 |& B
                  ;; false for a non-intersection patches.3 G5 M. d6 A8 |% ?+ V
  my-row          ;; the row of the intersection counting from the upper left corner of the( k' {) ~) q  ]6 z( g. E
                  ;; world.  -1 for non-intersection patches." B' |5 G3 x4 m
  my-column       ;; the column of the intersection counting from the upper left corner of the
+ x0 [; S9 `. K* C                  ;; world.  -1 for non-intersection patches.7 v5 k% Q2 y" J8 V
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
3 t% z8 b. t+ Y& g6 F- g7 u7 T; X" _  auto?           ;; whether or not this intersection will switch automatically.2 r) u6 }7 _2 l  C  K8 _' K- C3 M# C
                  ;; false for non-intersection patches.% a  G4 P3 d" B9 _  W; D
]
# C: x( ?# M1 _" f1 l- c7 S8 m6 ?8 ?" B" G

4 [6 Q+ \. v' ^;;;;;;;;;;;;;;;;;;;;;;
4 M6 R: U  w: N1 [;; Setup Procedures ;;
0 J0 h0 H$ S; w3 T; R6 E0 y;;;;;;;;;;;;;;;;;;;;;;% u0 r# ~! ^, u7 c& ^" A" O/ G
+ q. ~/ {+ b; \$ I/ U! I
;; Initialize the display by giving the global and patch variables initial values.) h/ I0 m9 |! V9 u7 u1 M, w
;; Create num-cars of turtles if there are enough road patches for one turtle to
' b2 x5 u& e4 o; y2 j& v# D;; be created per road patch. Set up the plots.3 m  i7 Q% O! s; }
to setup
& ]# @& M. o+ f5 y% C4 W  ca
$ i: l3 O( J7 l7 |* q2 B; j+ W  setup-globals' \. m& f; t& J
$ q& x- Q0 R2 ]# a" U7 Z2 G
  ;; First we ask the patches to draw themselves and set up a few variables7 ?. ~5 A9 f, [% g6 o
  setup-patches; a! o/ k8 ~: I4 G6 R7 i% r
  make-current one-of intersections' ~; [! _9 u" ]) m9 J' i" c
  label-current9 T( p. @/ V. i6 f5 W7 r

' G7 Q: V0 f# o2 L  set-default-shape turtles "car"
, n5 V: G7 U5 {! ?# g. y
6 W# l- I" c# L# S$ }  if (num-cars > count roads)4 t0 E& M$ w+ M: e; `7 r
  [- }; K0 h9 i6 Q' J# w/ \( y' k& P
    user-message (word "There are too many cars for the amount of "$ {4 u! A6 _1 F4 g0 W' t5 M
                       "road.  Either increase the amount of roads "
' R- x+ L" g& D& K. R                       "by increasing the GRID-SIZE-X or "
3 d2 P0 b. E4 z& ^& `                       "GRID-SIZE-Y sliders, or decrease the ": m8 z5 B& x& M' `( [  z* _
                       "number of cars by lowering the NUMBER slider.\n"
6 [" J4 f. y2 h& L5 ]& Y                       "The setup has stopped.")
4 d2 d6 @4 D) [/ S& G; {    stop1 R+ C  [  c, f/ J' x& H
  ]
/ T6 S& E+ [8 Y) M, B3 |8 k. N$ e: ]4 Y& w
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
* O: Q3 [! I8 u$ k" \  crt num-cars
' _% y+ c5 ^7 `: Y4 R  [) K$ P* j# A5 T/ M0 ^! a0 K
    setup-cars: ~' f4 P2 T% @3 E6 K
    set-car-color
8 U( M" ~2 N% [4 N% f! M8 ~    record-data; v) O" ~! z& j: ^/ N( `
  ]
3 a  l2 G( y4 g( ~( k
( n+ U1 `: s1 t8 B) b. U  ;; give the turtles an initial speed4 k  ^7 v" T& e+ B7 q' |  u/ T+ E
  ask turtles [ set-car-speed ]' n' v7 f% v0 M, X
1 L5 n+ P* d5 C3 x" S
  reset-ticks4 V9 Q; W* H& w, U; t: Z% C  e
end
! T6 f% @' q! m# U) B2 }9 M+ n: E2 R; W+ O' i
;; Initialize the global variables to appropriate values! Q1 f! f' F! B7 ^% r
to setup-globals  j+ y! \9 N* ~7 c0 |
  set current-light nobody ;; just for now, since there are no lights yet3 [  y' p3 U7 @8 J2 l1 n& S9 }! J
  set phase 0/ L- v( Q* y3 p; ~" C- t, e6 C
  set num-cars-stopped 0, Z" _! H' H7 u; C+ W& ?" s
  set grid-x-inc world-width / grid-size-x9 V2 b& y0 d. d) H! ~& w7 m
  set grid-y-inc world-height / grid-size-y( t/ H6 c7 v6 V3 W, F! K' W7 ~# y
, j* _+ G/ n+ E0 n( p
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary* {4 L. z* k* @- ]7 o( E
  set acceleration 0.099
7 d0 s/ h* V% o. F1 pend3 {+ O6 d* y' I) o

* }+ ?9 a: [' ^;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
5 r0 ^7 A0 q$ c4 c, E9 t;; and initialize the traffic lights to one setting8 e4 w5 T2 ^/ x* h5 c7 Z. [+ T8 F& E
to setup-patches
9 [  y5 w) B5 K) z5 A+ q  ;; initialize the patch-owned variables and color the patches to a base-color, ^1 q$ r8 O0 k* @- B+ w) Z
  ask patches
3 w1 W4 u! L0 J4 H* c& ?  [8 O% m7 z. Y: [( I+ |# j
    set intersection? false" V2 O- k6 b  p; O+ L& Y7 m
    set auto? false1 E2 @- Q+ @2 K/ U* `) k
    set green-light-up? true
! X  H$ O6 H) `5 l    set my-row -14 V+ M. R! _& n8 p- e6 P; |
    set my-column -10 A: [3 k- `: N
    set my-phase -1/ g  b; |: t, }) `0 {" U6 a" r
    set pcolor brown + 3# M5 L- A* C- K7 K
  ]! T2 J+ K1 M! S& o

* B5 n, L5 H; ?) n, d) M8 U  ;; initialize the global variables that hold patch agentsets/ b+ e, ?" j5 x
  set roads patches with
  t) ]# |( q& q- k& ~5 b    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
# ^& i+ {+ N# `- D: G& @* F    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
1 U3 k% t; }& l$ s! q  set intersections roads with
% L0 t! c! P7 R& t    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and6 l! c( a$ j% C
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]5 S# Y6 o( B# X. z2 ]
' H2 j; c& F5 n4 h3 k8 p) L0 U
  ask roads [ set pcolor white ]
5 T( W) i* _" s    setup-intersections
9 V# J# G' d' ?! Z1 f) \# e) e  hend) ^4 H* _1 ]. l. o: C3 j
其中定义道路的句子,如下所示,是什么意思啊?
2 j( x+ Z8 H1 b0 O' u& ~9 b+ ~ set roads patches with
1 J! ~/ _1 l5 a6 S# d, b( U    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or6 y% M" p9 A' d: j
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]; x, i/ m+ u1 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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