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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。
( t0 d( n* k( ~0 [- bnetlogo自带的social science--traffic grid这一例子当中,9 f% I9 y$ u1 A
globals
$ g7 F" i4 T  u0 v[
6 \: K: l: W, L2 U) k  grid-x-inc               ;; the amount of patches in between two roads in the x direction
# U- b  M3 s# [6 t5 T  grid-y-inc               ;; the amount of patches in between two roads in the y direction5 r/ ^. {7 y" H6 w. z# [/ {
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if8 \1 h% n% ?) p
                           ;; it is to accelerate or decelerate
( V& x- X  Z- s" k3 I/ q# g8 w4 p  phase                    ;; keeps track of the phase+ t/ q5 ?  c3 Z" s& {
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure- ~' w8 K0 v6 R# s7 S
  current-light            ;; the currently selected light9 M$ T* Q/ b% i
- a! q: A$ E- D3 u4 a
  ;; patch agentsets
! B% Y, @- n6 f- W( ^+ M7 R/ I  intersections ;; agentset containing the patches that are intersections
: p3 H0 f' u. A) j  W0 b  roads         ;; agentset containing the patches that are roads
  _* U# U! |' ~]
5 a. v5 k/ o$ b" [! }, |9 w+ _0 a" X6 ^
turtles-own
( t7 M. u" `5 S! L/ I[3 C0 w% }" j  Y% y; `+ |
  speed     ;; the speed of the turtle
1 @" _4 C2 D. B' ]6 F) X# w  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
& `0 h: p* [% |# [  wait-time ;; the amount of time since the last time a turtle has moved
( |9 C1 T7 @# H: P, C- ^]8 A6 h6 c3 ?7 Q0 N1 o0 p: S
' m5 X. \: f; i6 a; p: ?
patches-own- b6 V# H( B, Z% L: r5 K- V
[( i: g; o& l) ^' ?) ?; z
  intersection?   ;; true if the patch is at the intersection of two roads* p) r1 U: @0 _* h
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
1 q2 `" w5 B+ u4 B' V                  ;; false for a non-intersection patches.+ N8 h. y- G' p! u  x
  my-row          ;; the row of the intersection counting from the upper left corner of the
& N0 t, k! x( C3 f: t                  ;; world.  -1 for non-intersection patches.5 l! ~3 o7 k7 Y% z) w
  my-column       ;; the column of the intersection counting from the upper left corner of the: b' W2 h+ e% ~0 b- ]/ g. h
                  ;; world.  -1 for non-intersection patches.% h: K3 l* [# V: i8 |' Q
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
9 W1 b5 }' l. Y% G* w. j& L5 y  auto?           ;; whether or not this intersection will switch automatically.
7 M9 J9 E9 x) h  k                  ;; false for non-intersection patches.! l6 q& P: g7 w/ g0 N% p0 D
]
/ V* N! `3 t! C% H" u
0 H4 \$ M7 }1 z- W2 A1 x1 H# x: }3 ?* Q! m$ [9 s. _
;;;;;;;;;;;;;;;;;;;;;;1 a& o: l' I( K' c% J- w3 P: h
;; Setup Procedures ;;" Q* Z4 G- y9 _' E! ]& p& l! k6 c
;;;;;;;;;;;;;;;;;;;;;;
7 Z, w+ B+ z6 e5 ^
5 U, p* h# c6 I- y: V. P' ?) s+ M. f: T;; Initialize the display by giving the global and patch variables initial values.0 R* ]/ {7 a# ^# `/ ?
;; Create num-cars of turtles if there are enough road patches for one turtle to/ E* \' H- F8 {
;; be created per road patch. Set up the plots.1 R2 Y- G' v% W2 H0 G6 i
to setup
6 v4 v4 U& c$ V/ t0 H0 O- B" K! A) i  ca+ n9 c/ O5 v, K. O5 e; ]
  setup-globals
9 s4 s2 B2 P0 v3 L) _- C- m; y+ z, E, L7 P) p* ?; J6 h5 B2 M
  ;; First we ask the patches to draw themselves and set up a few variables
( `, V5 e. m! C9 x6 [- @  setup-patches
, k& q" b9 z9 s3 S) J! {1 ~9 g# V  make-current one-of intersections: ?  Y9 J8 l' n1 y- b$ F
  label-current4 O8 ^' W0 V+ o+ U

2 d1 ?- t; w: [5 X) k  set-default-shape turtles "car"
1 j3 q. H9 a/ A6 b3 b; |' i; i2 f% h9 B' l* ^" W/ M( n4 |' g
  if (num-cars > count roads)0 e; P2 [5 e& J. f
  [6 I9 r0 P+ w$ `1 |
    user-message (word "There are too many cars for the amount of "
& \6 @% ?) _, o: s! R$ U2 I& ?3 {                       "road.  Either increase the amount of roads "
* ^- H5 Y( L3 F                       "by increasing the GRID-SIZE-X or "
7 p  U7 w% V1 }9 p* x                       "GRID-SIZE-Y sliders, or decrease the "
, z& s* T  j. Y" p9 B% `                       "number of cars by lowering the NUMBER slider.\n"
1 }" W8 ]0 C, A/ J8 k# A  N# z                       "The setup has stopped.")8 Q1 g$ |- N1 H' X
    stop7 N7 w; D' {+ H+ {1 [" }+ K# T5 ~
  ]% v& }$ o: K4 p+ o
, e9 d7 {. v8 Y( ^  d
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
5 x0 x5 t. @& j1 o9 z) |$ x- _/ z  crt num-cars
  {  D. D* I/ B" ]1 e6 m  [
+ A- k* O% h9 z/ I    setup-cars0 B3 X3 k* D; z8 C
    set-car-color
5 N- E% @3 R, j/ ~( C* i    record-data( b) F/ g% O7 S  v& T, X) R' ^& Z
  ]9 C8 Y: O4 X" C0 M7 G0 W

% t" j" n* x  Q" c# [* Z  ;; give the turtles an initial speed
3 H/ V2 x  K4 a4 j7 q& ]6 g  ask turtles [ set-car-speed ]! w4 V# U" \: q% F8 ?% n( O  ?) A; q1 F
# E1 Z7 L+ A' e7 i2 m
  reset-ticks
+ l% @5 D3 w5 e* b) cend
& W& U! w( Y- w1 r4 V& b8 u
% e- c& s6 n( ]% u  p;; Initialize the global variables to appropriate values
) _* T2 {) d$ q9 m, r1 J& ?0 kto setup-globals; {2 O( X! z. \1 c  s6 s: r
  set current-light nobody ;; just for now, since there are no lights yet. u/ c. K1 c  R7 B
  set phase 0
1 a! Q4 |& n7 j, a% o/ U; I6 W  set num-cars-stopped 0
& i+ F; e. M: P2 ?  g  set grid-x-inc world-width / grid-size-x
6 s* h3 E4 t+ u( v- B3 |  set grid-y-inc world-height / grid-size-y0 j: C% j4 H$ r0 _0 [+ h& V

* V  J3 k8 c, f: P9 P# ~; Z  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary9 y+ m: s3 T0 E
  set acceleration 0.099
' \( p) @2 C7 q* w# Zend7 u% l- v+ e$ a& t8 b1 c, h

: q) W7 _' e6 X. G6 O$ c;; Make the patches have appropriate colors, set up the roads and intersections agentsets,' i; ^% o. Z4 d+ e
;; and initialize the traffic lights to one setting
" W$ h( Z& d5 eto setup-patches
7 I) y; S% m9 q) t" e3 y  ;; initialize the patch-owned variables and color the patches to a base-color7 C; A* A  {+ H( X
  ask patches
! X5 N6 Z8 ]% @9 D  [
7 j* _, D7 M# M; l    set intersection? false
5 }( {9 |! q" B5 @% A  A    set auto? false. B" j/ f7 I% p! Z$ X8 m
    set green-light-up? true" p3 H, O% ^) R+ _2 K- ^
    set my-row -1
6 X5 [. Z4 d2 m    set my-column -15 O, j( U$ x7 N, g) @* p& x0 P
    set my-phase -1
8 ]& G3 h. z1 x, f$ Y# b7 C    set pcolor brown + 3
, P  Y1 o) h6 ^8 D- x0 k& x3 q% v  ]
- K8 D, q7 x" R) N  J8 {$ ^/ ]- F3 b; x' H5 X* j, w5 ]* k
  ;; initialize the global variables that hold patch agentsets
' s* A6 e0 X0 _5 d$ m  set roads patches with* T* Z/ s/ z. l& c( _
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
1 [( h! Y7 L) Q2 Q: S  _    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
# u; Q* f7 ^% |. }  set intersections roads with. B2 r4 S) ^6 s. L; R
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
$ O1 x3 B. |- a$ D9 H    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
+ X7 l0 B! w8 g4 j6 A1 m6 W4 [7 R+ H9 @& q0 N  ^" X7 q. W$ v% w% O
  ask roads [ set pcolor white ]
0 |# [) P+ H) W/ r$ n$ `    setup-intersections- ^+ Z( \# B' E
end# o( q( e; w5 C
其中定义道路的句子,如下所示,是什么意思啊?6 E, X) |7 X8 s" y$ R& c! W
set roads patches with" g& J( G' }* d1 y" T
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
% L1 g* S/ k* T  r    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
3 p7 L$ m0 E( E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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