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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。5 [4 m" p! [) f' p/ z  {/ x7 _
netlogo自带的social science--traffic grid这一例子当中,* {9 e; c+ X/ Y8 D# }& i- [4 o) ^
globals' Q' \, f$ ~9 Z% P: O
[6 R: G, i, ]1 S. I
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
, y$ W) _7 [! A, P: r5 k% b0 c  grid-y-inc               ;; the amount of patches in between two roads in the y direction* y$ a& j. j' ^* a6 A7 j( M& g& [
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
7 Q9 K6 }) i) }% L/ g                           ;; it is to accelerate or decelerate9 L) P& h# M* r0 `
  phase                    ;; keeps track of the phase
& H, ^! w& O4 g2 a/ @; |% I* ^  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure8 f' R+ i. \( o  v$ ?* L$ G
  current-light            ;; the currently selected light- |7 m1 i( _* c# d% Z

5 r3 e  ?3 a! R0 Q' R: a  ;; patch agentsets3 H. r- X5 W2 L8 `' u' m" F2 U* x# ^
  intersections ;; agentset containing the patches that are intersections
: Y: V+ O1 T4 P  roads         ;; agentset containing the patches that are roads7 R  {% O! D: j
]
& k2 ^- H) T- ?- {7 I0 Q8 v* d- S' C' g1 Q" h$ e
turtles-own- W& Q% m! `7 t- e
[
2 R0 I% l3 `* ?  s5 R5 \8 T! M8 H; C  speed     ;; the speed of the turtle
+ W% d' A' O$ L, a( V& R  up-car?   ;; true if the turtle moves downwards and false if it moves to the right" d9 U* z/ [; F& F
  wait-time ;; the amount of time since the last time a turtle has moved* w8 x7 J+ R5 ?* U4 x6 _* \) f
]
$ Z5 p, K) ~' k, ^8 U8 D0 Y8 v, Q7 p3 l6 |9 C4 v
patches-own- {# E" A* k/ K2 a9 I2 _
[+ O$ Z1 S# \# e5 f
  intersection?   ;; true if the patch is at the intersection of two roads( D/ e# j0 E2 |- h! w4 w' J* @
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.$ H4 M6 z+ R0 q( D  T
                  ;; false for a non-intersection patches.3 L2 j& A- k0 \" {$ U, `! S
  my-row          ;; the row of the intersection counting from the upper left corner of the2 N9 Z6 }% {$ X6 E1 {* A2 t$ R
                  ;; world.  -1 for non-intersection patches.
% P5 {5 v" a4 J: m  my-column       ;; the column of the intersection counting from the upper left corner of the* m& Y# @+ R# ]) q& ]1 ~1 U
                  ;; world.  -1 for non-intersection patches.& e4 Y+ X8 p( y9 T( |; p6 ^% ?3 [
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.( G9 T! @+ k0 ~1 O+ B! i
  auto?           ;; whether or not this intersection will switch automatically./ ~. `! u6 Z* E# D/ O# n( i! _, W5 m
                  ;; false for non-intersection patches.
+ {/ z: j9 I* d6 V2 k/ N& q8 Q/ T& d]- Z4 B" c; z1 l- ?3 h

/ h( T5 [. _* @: H4 q! g9 j- }
  K2 n+ [% \' H6 L' U6 J! e7 R;;;;;;;;;;;;;;;;;;;;;;
7 b$ u/ _* U; R4 G( X;; Setup Procedures ;;
3 l0 Q7 o# C5 [5 U- J;;;;;;;;;;;;;;;;;;;;;;
/ F: c$ S% Y, r
$ b1 \1 }  s! u7 M- h  O& R;; Initialize the display by giving the global and patch variables initial values.  [: W' s  R" \8 c. y- ]/ p
;; Create num-cars of turtles if there are enough road patches for one turtle to' o9 h$ ?' `' N- Z
;; be created per road patch. Set up the plots.
9 x# p5 r* Q) p$ r. j2 i* _to setup* P& B7 h3 f) ~0 ~. x0 j6 B
  ca( g" a/ G; N4 F3 q" r# j
  setup-globals" Y/ X' I* Z  a
% }- i; X9 n2 N8 J+ R4 _
  ;; First we ask the patches to draw themselves and set up a few variables
6 i9 l# C$ m0 `  setup-patches
6 T2 E! j3 ]- Y& y* D  S  make-current one-of intersections7 i! |3 L) R3 l- i8 e1 y
  label-current; D. ^# G* @; q- p
5 p$ ^0 R7 q9 ]2 V6 }6 A
  set-default-shape turtles "car"( K: J0 T3 ^3 U( D, W) A

' S8 W, s. R1 l1 W) l  if (num-cars > count roads)
/ [3 Y& d7 }  U  [* v; ]* I; \% a$ Y8 o
    user-message (word "There are too many cars for the amount of "' T2 d4 }3 q: `/ r- q
                       "road.  Either increase the amount of roads "
! T& g0 B9 s2 h9 a7 `& k                       "by increasing the GRID-SIZE-X or "; U2 N) h! }; L5 X2 V' ?
                       "GRID-SIZE-Y sliders, or decrease the "; i* x& I; j: O9 I( S# l7 j
                       "number of cars by lowering the NUMBER slider.\n"9 k) d0 k, L# X- N' b; C
                       "The setup has stopped.")' K2 _; b! {5 a. }6 L4 y% f( Z
    stop
* F# P& d# W1 Q& D; ^3 _# }  ]
% p( J: L2 W1 R  b+ n( ?! f
6 g& G, n0 m7 Y* `8 N( n  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
& O6 o! O4 G8 }  crt num-cars
& \1 v0 m' W/ m: T% x" c1 p  [( Z' w3 q  w/ t' m- [
    setup-cars
, _/ R) x: q- s$ }' U' i    set-car-color
( \/ N6 I# i& ?6 M5 f    record-data
) M2 y* E8 }( ?6 u  ]
% F6 |5 w* C/ _0 W# |
* r$ E: s8 E. h$ z! q8 A8 G$ ~( @  ;; give the turtles an initial speed
0 j* c# T, I  x; ^2 u  ask turtles [ set-car-speed ]: A. q* I3 D. ]1 |0 w

2 `9 k4 D( V& D! p6 H  reset-ticks3 }, ?2 W1 s- S, o4 W" }
end" |! D  i% o- `% l' ]! Q

9 R) `* E& A- h' P% W;; Initialize the global variables to appropriate values
8 l- k5 S# \/ ?# H; r: e' a: h5 ]to setup-globals- v, X# J5 A( ~
  set current-light nobody ;; just for now, since there are no lights yet
2 y3 `0 g% l, Z- c. k  set phase 0  ~7 c, \+ k/ T
  set num-cars-stopped 0' Q4 e! d" y) V3 o9 _) s# Y/ t! e
  set grid-x-inc world-width / grid-size-x- \  A( D0 D; Z% n- o
  set grid-y-inc world-height / grid-size-y
  G5 [" d$ D% r8 x& e
' ^1 A( f% ^8 B* e4 N8 M3 K  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
, F) P9 f# {4 y" B  set acceleration 0.099
4 v* n9 m9 v# @  Z; Z: dend# q; H3 ^. t) Z0 p( _$ r7 g! L
& e$ H8 [3 n4 {. t
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,0 K7 S- ~' N5 ], R
;; and initialize the traffic lights to one setting3 ^% {( W  e! Q5 T
to setup-patches9 R5 d9 O. }* R7 J* H1 y
  ;; initialize the patch-owned variables and color the patches to a base-color" b) l/ C0 X4 B4 M. k6 s( d
  ask patches) n  e2 o; z4 p
  [) H% ]+ ]- e, L+ T% q
    set intersection? false* E$ T* b7 |' k$ p& c# v
    set auto? false0 [# ~7 J" r: w( s; @, `
    set green-light-up? true
; {, y  k" x' ^1 S" E: `, r5 r6 k    set my-row -1: K; U; z* j/ U2 y9 ~
    set my-column -1
! F% ^0 |- N  G% v: |    set my-phase -19 g  P( Z# m* E4 p& f; P# L$ T
    set pcolor brown + 3" G6 x' r0 f5 }% q
  ]
  b6 o) f) v+ C0 U3 C% o  ^$ W. G4 I- F
$ f9 ?$ p, n1 F7 `3 D3 e  ;; initialize the global variables that hold patch agentsets+ R3 M+ c' N( @- |3 V
  set roads patches with8 S8 I' B0 Z4 I: ?
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or1 @  `% m' M5 c! O% v
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
  f+ s+ I+ I. V  set intersections roads with4 Y  B# h0 P) m& ~3 f  d7 {
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
% s$ h# @+ e& f    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
2 p' d% I2 g  _  A1 M: |4 a; I0 z! s4 G3 O) o
  ask roads [ set pcolor white ]
* c- l. g3 N4 x8 R: w- U# G    setup-intersections
0 C" n8 Z  F8 V: Xend
7 H  t* r# ?# P0 E1 \! X5 F其中定义道路的句子,如下所示,是什么意思啊?8 A2 ^) X" J0 @8 k2 r4 x
set roads patches with
9 V2 x, y' k, X  Y& r    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or8 p, ~9 |. s. X- A( r2 r
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]2 \, q% F) k/ w$ C6 b
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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