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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。' c5 @; r) t8 G
netlogo自带的social science--traffic grid这一例子当中,
# R8 Y3 l+ T! N! u4 [globals
( }; F  i: @& L6 a[/ S& v( F6 u$ }4 s- ~3 B: R
  grid-x-inc               ;; the amount of patches in between two roads in the x direction4 u) m6 ~. ^. X% Y0 }
  grid-y-inc               ;; the amount of patches in between two roads in the y direction5 i9 {" j/ {; K& I1 h9 V1 }7 {
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
8 z6 H8 H) _2 z1 G& n7 y6 ~+ E                           ;; it is to accelerate or decelerate
" f! t$ k! Y3 T% l) W+ U  phase                    ;; keeps track of the phase( N, @" Q# j/ M. G! _
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure  d: `$ ]# L" l* q0 F
  current-light            ;; the currently selected light' R3 r% ?. J1 S& A

, F6 R  W% q# c9 C9 [8 b4 n5 A  ;; patch agentsets% l3 O& s; [3 v+ j1 i" C: g
  intersections ;; agentset containing the patches that are intersections4 U) H8 _6 j% I1 Q# f9 r* k  O% d
  roads         ;; agentset containing the patches that are roads
* ?! m. c/ [5 \- o! C7 H6 L]3 K4 o8 L& s( L& M

5 T+ I3 S2 ^8 u7 F+ Dturtles-own
- y9 q; o2 B* t- p+ `[
9 C& j8 O, [/ w. U* U  speed     ;; the speed of the turtle
5 m' H; x+ D+ ?  j+ h3 ~  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
4 K' ~2 ^2 p& U, U! Q; @! U  wait-time ;; the amount of time since the last time a turtle has moved; N! Q+ @5 k' a; S
]
4 }( ^' t9 I3 d/ ~+ ?) W. r' M7 D5 [
patches-own
7 n# l8 J' m7 c[( N% @4 O6 k' {) f9 y) z
  intersection?   ;; true if the patch is at the intersection of two roads" T. b! \+ {8 s, C: s3 Q, H
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
: m/ R! B2 S9 {$ y* Y. }8 \7 F                  ;; false for a non-intersection patches.0 @$ P2 o3 {- U  w, v3 f
  my-row          ;; the row of the intersection counting from the upper left corner of the8 X" q6 D4 T- v3 a2 H( R
                  ;; world.  -1 for non-intersection patches.' a: V& `" d, x$ w
  my-column       ;; the column of the intersection counting from the upper left corner of the
+ W6 l. \0 F2 N+ \                  ;; world.  -1 for non-intersection patches.. T( f8 m" H( O. m
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
, E' X. a$ m- X$ g; m1 D  auto?           ;; whether or not this intersection will switch automatically.. O: l% _( ?1 ~" D' T7 x0 L- e
                  ;; false for non-intersection patches.- S3 R! n* b5 z1 w' R2 \6 [
]
1 @. ^3 ]2 c' j  m* G$ d1 a3 Y+ C' s/ s3 D' c3 j  g, o) ?

8 p* f5 ^. d# C% |( z! m;;;;;;;;;;;;;;;;;;;;;;2 ^8 G7 y: W" d( Z6 z
;; Setup Procedures ;;6 y; V" A2 ?" V- y3 j; H' C
;;;;;;;;;;;;;;;;;;;;;;
# ~# x% S& ?' l/ g& v3 ?4 y+ ?, R9 Z( q; i7 F, D, \
;; Initialize the display by giving the global and patch variables initial values.7 Z6 S- x" Y- i, W7 x; W6 w2 L, q
;; Create num-cars of turtles if there are enough road patches for one turtle to- B* o- u' i* u6 A. ?+ T( Y! h- O
;; be created per road patch. Set up the plots.: Z# o+ m! f6 X2 F
to setup
: ?) ]+ F( @& l5 u3 w" R  ca5 m* s' d. O4 j+ E, a# a; ]- F2 V
  setup-globals
# S) C8 x9 m- s0 q3 L
4 Q) e, @9 h( h3 [3 p. l9 {2 ^- m  ;; First we ask the patches to draw themselves and set up a few variables
* r  {( x) u: F0 `7 {  a3 r% i  setup-patches( J1 l5 T7 p0 O+ d* b  l) l! R
  make-current one-of intersections( z+ M. |9 j# y) F  B& ~
  label-current, d* O6 f6 {# z8 _' `; h
, ^6 V4 }% E) w, x
  set-default-shape turtles "car", A, p% r2 b6 U8 n4 |( ?+ Y
; S' f* B$ k) e, d' D& Q
  if (num-cars > count roads)& X5 o/ u7 {' v' Z+ K) Y  a4 _/ C, A
  [
3 x1 ?7 G3 ^2 _7 f4 z    user-message (word "There are too many cars for the amount of "
& c1 {  P: L- F' \+ l                       "road.  Either increase the amount of roads "& h0 z$ L6 j3 r- R; P
                       "by increasing the GRID-SIZE-X or "
  E! L7 |& @7 S8 P" U, e7 F% f                       "GRID-SIZE-Y sliders, or decrease the "
1 [4 s* T0 m1 i; T0 U0 R# m                       "number of cars by lowering the NUMBER slider.\n"( w  E5 {: T$ t0 V- P2 Y
                       "The setup has stopped.")
3 E9 A  P4 R; W" \    stop
3 R% k& Q% v4 o) O  ]- k3 S: O  V$ d! e9 S

2 F$ m/ j$ i% |% B6 `  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color5 e8 L) g/ t% S+ S9 G
  crt num-cars% A6 S, |! F, Y1 O: p
  [/ `$ x- |$ s: |
    setup-cars/ l, L" T4 P2 K7 I
    set-car-color: p7 `0 L3 O% E6 ~. N5 e& p
    record-data" D  [4 n6 j6 ]# k/ i$ v0 p
  ]
& y, a9 p& v- Q
" u& W# m; B& {  ;; give the turtles an initial speed. A% B! j( `& B4 B4 }
  ask turtles [ set-car-speed ]
2 f. _$ ~2 I$ M' I3 t/ v
( K' r3 I: N+ S4 U6 L  reset-ticks
8 f# V5 v" a4 z" h3 n2 e4 aend
9 I8 i; y$ s! E, ^
3 x8 T4 U# m" a/ D/ m$ W" f;; Initialize the global variables to appropriate values
/ u9 x9 F( Q7 Ito setup-globals
4 g* T0 W$ h; x! m8 p  set current-light nobody ;; just for now, since there are no lights yet
) v* ~" c' v( `) f: z. G5 O  set phase 0
* n8 ~3 Y: \9 A% s3 X3 s/ V  set num-cars-stopped 0
6 O+ a# Z7 I0 Z* E0 A  set grid-x-inc world-width / grid-size-x; h+ N; M& b4 b4 D6 G
  set grid-y-inc world-height / grid-size-y, T6 ?& V$ y) S  Q1 Q  `- ^3 ]
! f1 G  O* N0 X5 [8 Z# b
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary3 L( ~8 z$ w- @. i1 O
  set acceleration 0.099
+ z9 M' [! s3 z+ q( lend: f/ n4 x4 z) l! t  ^( V% s7 @$ p

; ~0 ~/ x* c# Y9 n4 u' N6 D. M: e;; Make the patches have appropriate colors, set up the roads and intersections agentsets,: V3 |: r1 D4 M8 l$ V
;; and initialize the traffic lights to one setting9 X1 l5 ?4 p' t$ h$ K! q6 m
to setup-patches
8 l, N- Y  S1 j, L0 e0 F4 B  ;; initialize the patch-owned variables and color the patches to a base-color8 @1 b( A: x! y, s$ v  E
  ask patches- I% ]2 X) {( `+ M8 Z/ y1 W
  [& ^' m& O* R- q& V/ k1 R
    set intersection? false
% Z! k6 n5 R' A  m' v    set auto? false
( ^0 p2 K" W: q; F+ U4 t# X* q8 N    set green-light-up? true
3 Y2 X" m$ W4 x5 Q; @' a  f, f    set my-row -1$ I' b5 W+ U1 g' H) d. f
    set my-column -1, A1 p4 W6 J5 g6 G5 C0 T
    set my-phase -1+ s3 Z" [" I. k) L3 m  h4 v4 S$ S3 \
    set pcolor brown + 3  d, a" D. B$ H
  ]
) n- t9 A' B1 H. K1 N  r" c( B. b) D5 h# F8 t- r) [
  ;; initialize the global variables that hold patch agentsets, f, B. `. d: V
  set roads patches with
0 i; @; `7 q$ I' I+ o    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or* K4 V- {) t, y# r9 O& R0 L2 O
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
  }7 p. F0 I- e+ q  set intersections roads with
/ t: J9 J3 S& x' f    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
9 i; V. w% q- L0 K    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
1 q4 {  C( r/ o4 ~8 C
* C2 m" X7 _( A  u6 h, S  ask roads [ set pcolor white ]
1 l/ c5 n/ P6 }4 ?6 z    setup-intersections; Y+ a0 j0 z4 ~0 I$ ]- v. |3 e" g! _
end
' Z( V- u& u8 g. c5 ?! C1 G* k. W; \其中定义道路的句子,如下所示,是什么意思啊?4 g& L; P2 b& X% ]; w6 s! c3 s. k
set roads patches with# o# O$ u6 T7 |" }  G( b  x
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
2 L- u& n( j- E* [& u    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
% G; j6 c# U9 @& ^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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