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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。/ y. B+ X- L/ G0 o$ Z
netlogo自带的social science--traffic grid这一例子当中,$ b2 ~7 G" Y, I$ y$ Y- c
globals
1 W3 {! j! C, ^2 o" h! r[
3 ~; L9 Z/ V0 A/ s3 g; j1 g  e; d  grid-x-inc               ;; the amount of patches in between two roads in the x direction9 d4 q, p5 g5 s4 [
  grid-y-inc               ;; the amount of patches in between two roads in the y direction
, }! ?3 W" X! T* N# W. L8 Z  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
6 [( ^% B1 U1 O8 N7 [                           ;; it is to accelerate or decelerate
5 b5 X/ V' a% Z4 [; v/ b7 Y$ f  phase                    ;; keeps track of the phase
4 Z# H8 s) a! ~1 |3 |4 Z  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure% l1 n: ~2 s& B, W) v
  current-light            ;; the currently selected light2 V' t! [. P& Z. l% i+ E

7 `% @- X8 ~, B  ;; patch agentsets
" H$ C0 U, [; C8 r0 q  intersections ;; agentset containing the patches that are intersections$ r; r7 ^) K$ c7 S4 F# G
  roads         ;; agentset containing the patches that are roads
) S/ l, p$ R1 G% p/ Q/ g& K]7 v3 W# l3 Y: ^+ c2 E" _$ F; h6 Q( j

2 F  L) D8 g. e' |5 oturtles-own
* d* v3 E* X, u* v' m$ Z+ f[' I9 f$ A1 C+ C, G8 a: U( l
  speed     ;; the speed of the turtle3 w! ?  G- d1 `" ]3 l
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
* q  {8 ~1 P# U3 e& g3 g  wait-time ;; the amount of time since the last time a turtle has moved
- q# N3 x& h" N6 ]& {]0 N* X5 W0 {$ s5 U  ?: }

  }1 R  a9 ]: J( `. t( F0 Gpatches-own0 d) V# R! }& `# _5 y* D' ]
[
; k( C" l6 g$ q) B% `  ^* I  intersection?   ;; true if the patch is at the intersection of two roads
5 G  O0 t8 N) m) U1 v6 E  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
* c# F/ b8 B/ J/ {. N  t. Q                  ;; false for a non-intersection patches.: u* V' v2 j# |$ K% O6 E
  my-row          ;; the row of the intersection counting from the upper left corner of the' ?2 ~& p2 ]5 }1 H7 }
                  ;; world.  -1 for non-intersection patches.
, ?) l9 J9 X# C4 [" |' X5 y  my-column       ;; the column of the intersection counting from the upper left corner of the
; K$ l6 T# R2 H5 H* _) E2 b2 e+ `* L                  ;; world.  -1 for non-intersection patches.
3 ~$ F' E! @: M* F- Y  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.5 ~4 u$ G' M: f
  auto?           ;; whether or not this intersection will switch automatically.
1 V: z! f+ L& D! y" }  g0 x$ m                  ;; false for non-intersection patches.
  g$ u( j* K) |$ U]7 k+ T$ m% M) g- x

3 w1 ?1 {( [% }& @
) C2 Y/ Z' e1 c8 t. B# a;;;;;;;;;;;;;;;;;;;;;;
3 V7 q! Z0 G+ e" j;; Setup Procedures ;;  A9 _* O9 \5 q) L2 e; U! g0 ^
;;;;;;;;;;;;;;;;;;;;;;1 [' V" i1 E$ d! d7 q
! ~7 {& T4 c' X0 l( Y- d
;; Initialize the display by giving the global and patch variables initial values.
5 d! d4 d4 s) X;; Create num-cars of turtles if there are enough road patches for one turtle to9 }8 z* b: K6 Y7 W2 ]" f
;; be created per road patch. Set up the plots.
6 l$ W, }, I" Xto setup
) t2 }- D" ]3 O' q% @  j* D# ^  ca
/ [5 K9 v# E7 ~  E/ H  setup-globals
$ m- s  u$ \: S% C" ?' z8 x7 L4 m. p( j( |5 G  H
  ;; First we ask the patches to draw themselves and set up a few variables/ u: Z" G3 u3 z/ f8 c
  setup-patches
# `7 `5 ^( z! c1 _  make-current one-of intersections
6 ]6 M( n- R0 l  [  label-current3 |; X9 X3 N$ w( O  ~% d

# f! Q) P, O# F1 m* r$ f9 |4 a6 Y( i  set-default-shape turtles "car"" b( R9 v) @# t

+ H4 E+ s/ H( f4 v, r6 o  if (num-cars > count roads)( \0 l2 f' S8 M
  [
% f3 Q' b% _$ l    user-message (word "There are too many cars for the amount of "
+ V( I0 [7 g7 j5 H                       "road.  Either increase the amount of roads ": g: @9 l+ Y% D
                       "by increasing the GRID-SIZE-X or "
, ^6 |8 {* Z, t" M( O; W" b                       "GRID-SIZE-Y sliders, or decrease the "
2 x- |) }4 D+ t                       "number of cars by lowering the NUMBER slider.\n"5 i+ e$ d8 F' h; s
                       "The setup has stopped.")2 R4 N! g8 B& Q( e8 N9 q5 F4 x
    stop
1 F& c* N  J5 R; c; w1 j% K  ]+ G! q( M3 u+ Y

, h6 H+ R. C* U' k+ v  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color* \+ g. V- Y8 p: L- v& m
  crt num-cars. E  a; J- _7 R* Y
  [
% y' y7 A! a/ d% |    setup-cars
+ E: y8 O' f! k4 O5 J& k& H# u5 y9 U    set-car-color
/ [1 A, q+ {$ f) Z0 T" S, Y    record-data1 k1 H5 d$ V1 A, d) P1 S
  ]$ L6 {% R( P* ]' I1 o) V( u

9 ^  r: q( h* h0 ]! z1 Z. l# m  ;; give the turtles an initial speed. {  b* |7 [7 |! H9 |, n
  ask turtles [ set-car-speed ]
4 m" Y3 S8 e- t& M; J& L
4 D- ]0 A  ^2 w% j  reset-ticks
* [# A4 L' b, Z4 F5 v, z* Z7 a, iend
* m. X: F2 P9 L2 O7 [$ K+ p& X- \& @
;; Initialize the global variables to appropriate values
* j/ c4 w* U9 P/ q! Dto setup-globals
! i1 c9 d% @5 w+ q0 |  S  set current-light nobody ;; just for now, since there are no lights yet
; A' o/ T0 t7 }/ h% D  set phase 0
* P$ X9 t6 F6 L8 F% R  set num-cars-stopped 0
: p" s- W1 Y+ D8 w4 }& b3 j8 W, A  set grid-x-inc world-width / grid-size-x4 n8 \' I$ V$ i0 I0 H7 o& n
  set grid-y-inc world-height / grid-size-y. R" u+ J! u" G( e- {. k

+ v) x4 x( z: a% i% b9 f  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary1 n/ m. C& ?( W) W* U+ I" f% E
  set acceleration 0.099
4 A& i9 e& o: d3 w0 d+ nend
: T6 Z# {; n- y) p# d  Z- D( p9 R+ z6 Q0 U, ]
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
* A& u; {9 o* y5 U. C;; and initialize the traffic lights to one setting* |2 N/ ^, ]7 S- C, \! q% I- x
to setup-patches
1 p) R7 P& z+ A  ;; initialize the patch-owned variables and color the patches to a base-color$ n5 e1 `2 Q4 u! j! z* a* }) b
  ask patches
8 [) T$ y* K7 k, P' S) r* Z  [" D. j; U1 A- {2 W: }
    set intersection? false
# z2 e, J6 }- l" |    set auto? false
' x1 Q+ d- M- W. r& q; p8 e    set green-light-up? true3 v* V/ j7 F, c  |0 U% X6 g
    set my-row -17 Y+ s8 d9 C6 @( L9 w
    set my-column -15 S" @, E* I! c( E
    set my-phase -1. A7 L+ [3 C; f' _( Q
    set pcolor brown + 3
/ E6 F# H7 K5 G! y; X1 o  ]
+ d8 o% r; j; c# e+ t# [/ s/ F7 C  l5 L, n, s  |
  ;; initialize the global variables that hold patch agentsets
8 x, u- D: e5 W+ f  set roads patches with
! q9 {4 l* M: }" |$ ]6 |    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or9 @( i+ R. K$ m1 l+ ]
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]" a0 S/ v3 H$ {& |
  set intersections roads with# Z/ }% p: ~! N3 C& Q" p
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and1 w' e" b' A' c6 s4 T6 B3 M! X+ T3 u& \& P
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]  Q3 E# D& Y& ?; ^% x2 V

4 B/ X/ T6 ]8 x& s  ask roads [ set pcolor white ]
" u  o/ |+ K0 g3 C    setup-intersections
/ a/ h1 q8 N/ [0 D# C) A* Wend
* W5 q) l8 o+ o9 j2 L7 |  l9 h) v其中定义道路的句子,如下所示,是什么意思啊?
- W" i9 A5 D) f0 f0 H set roads patches with
, G, e7 \+ f7 }    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
# a; n$ ?2 \' ]% W' Q8 P" D% H    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]9 p- |; K( I( Y
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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