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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。
' B( r# v; Z) p( s8 a5 Jnetlogo自带的social science--traffic grid这一例子当中,( h% W) ~0 \! b2 j9 b
globals, j% C9 \/ C  U4 n) P# L3 z
[+ n& l/ |( b7 H4 s; k$ c
  grid-x-inc               ;; the amount of patches in between two roads in the x direction0 E7 k* W- b9 q% {" U
  grid-y-inc               ;; the amount of patches in between two roads in the y direction3 b5 p9 U( [1 F0 d! F0 |9 d  ^
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
' P& R1 R  Y5 ?  U                           ;; it is to accelerate or decelerate
  d+ D* M7 C& @/ K5 n  \% B  phase                    ;; keeps track of the phase
  b3 s: N8 D" H9 u$ T& B4 ]4 Y  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
9 {0 B+ E8 l4 e0 x+ b+ ^  current-light            ;; the currently selected light+ m. N7 h8 M% x+ I8 |: ?

# Z) R# S7 _9 J1 ]) L8 s' w  ;; patch agentsets3 |7 J! ]' i, L! X
  intersections ;; agentset containing the patches that are intersections; q7 i+ r. D7 P8 m, z) ^2 g' V  @
  roads         ;; agentset containing the patches that are roads( U$ |% p1 [% I, {! u+ G+ n* U3 d' J
]$ x' T- b( Z9 A$ G+ `
" D! Y6 k9 S, ?. E8 I
turtles-own
% L- R4 k1 H4 G; E$ N3 x. @[! [+ {0 P. M1 Q+ v- W
  speed     ;; the speed of the turtle
! p) L4 W5 t3 N( M9 C9 y8 s  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
0 j: o3 f. D+ A  wait-time ;; the amount of time since the last time a turtle has moved2 O+ c1 Y6 k2 b
]
  o. ^" W5 ^1 |( O7 C
! w+ {+ W) D2 G8 W6 s+ ppatches-own# p1 O- i& r4 c* i9 B
[" K4 Z& u4 C0 i. a! U
  intersection?   ;; true if the patch is at the intersection of two roads5 B. f' }! P" V2 R5 M8 h" s2 {! l
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false., N0 ~/ t* C% |7 s
                  ;; false for a non-intersection patches.
0 P, L3 T/ |+ l" t  c0 `  my-row          ;; the row of the intersection counting from the upper left corner of the
3 l# t9 r5 U- N0 T                  ;; world.  -1 for non-intersection patches.
) k' r7 u' L+ `2 D8 v7 n; a0 \3 x7 \  my-column       ;; the column of the intersection counting from the upper left corner of the
* z/ T1 `) h, t7 n% y! c: e                  ;; world.  -1 for non-intersection patches.3 `5 P: T1 N/ q, t% J
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
" A. Y6 B/ n7 y3 {/ R1 N  auto?           ;; whether or not this intersection will switch automatically." y6 g- X1 m: `( e; j% f/ r7 X
                  ;; false for non-intersection patches.0 M, H# p0 f. G: z! f: ?8 @' L
]
; q* N! o4 @  F1 ]- L4 o0 B  E& G3 J

) A# `7 Z3 K; Q;;;;;;;;;;;;;;;;;;;;;;: _+ r. E9 Y6 t; w' O5 e' B. f7 Q0 e
;; Setup Procedures ;;
  z- E: q+ [; E9 n; ^( ?) q4 N0 X;;;;;;;;;;;;;;;;;;;;;;' V5 Z: R+ n' \
, r1 w- q/ {. B6 a& D8 Y* @
;; Initialize the display by giving the global and patch variables initial values.
& T0 f! O1 N7 w; }2 v+ m2 ^5 w;; Create num-cars of turtles if there are enough road patches for one turtle to
( h+ Y/ ~' T' J0 D6 f' a* Z/ Y  G;; be created per road patch. Set up the plots.+ j% y9 |4 _( x7 f4 I$ u1 d
to setup
) t/ a& B3 f/ E0 c6 k  ca
% K0 G; X$ ^" [/ N, k& N# J+ b4 e6 D  setup-globals
  c  m# x" X# X7 [* _- i8 h0 J# X: @9 h) k! C7 E  E
  ;; First we ask the patches to draw themselves and set up a few variables+ Z  P  G3 F( [- [. M- }, q, o
  setup-patches
5 h1 o; l! Z" M. J7 ^  make-current one-of intersections
4 y" Y5 q: V; K7 l8 ]2 T2 v  label-current; b2 M0 n; b$ f
" s4 Y0 A( @" e- Z+ a
  set-default-shape turtles "car"
# e/ y0 {0 V; p/ A$ M) I7 k9 H1 g2 f' i: ]' G( K" [' d) ~
  if (num-cars > count roads)7 u9 m' {7 `7 @0 n- D
  [4 @  Q" Q7 C, D( r$ Q: V$ B
    user-message (word "There are too many cars for the amount of "
: l! n4 A7 _8 f; ~& a! I5 M                       "road.  Either increase the amount of roads ". _9 J% ~' z1 x: y  u: O9 D
                       "by increasing the GRID-SIZE-X or "  o7 R; E4 \: O/ P8 N0 _+ u7 G
                       "GRID-SIZE-Y sliders, or decrease the "
, J; s; D% d8 N* ^; \                       "number of cars by lowering the NUMBER slider.\n"
! {6 Q+ I5 L. j$ E, \  q                       "The setup has stopped.")( _& R. C5 D+ C2 e7 x# U6 w4 r
    stop
0 X- f- z; f- \" x; g  ]# `% v3 P+ n5 [
7 L3 a0 p1 s' \4 o- H+ V
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color, h7 j1 ]- M$ [3 T+ i
  crt num-cars
: J, W$ m! ^8 Z$ v  [# S7 H, s0 [% y
    setup-cars
2 d7 }2 b7 x6 z% L8 N4 a- a  A0 o7 @2 S    set-car-color
; _4 V3 ~$ R5 g& C% c- Y' ?    record-data
& c, ]! F1 T7 j9 s' j5 s& ^  ]
& n+ `1 ~6 J! y% ~7 S* Z. A, I; {0 M5 c! ?2 g5 V6 K( e1 Y  V, X, H
  ;; give the turtles an initial speed: Q5 }# G; t& E0 U4 i, N8 N2 x$ T
  ask turtles [ set-car-speed ]3 }2 T" c8 c! h- Z

3 K+ c' O5 U. s* F  reset-ticks
4 P* A& B4 r- x- r6 X/ {end, V0 A9 y5 v: J9 i

9 N5 ~: |* P* \3 V) j1 p;; Initialize the global variables to appropriate values) _# e: h9 j! C& f- @. Y
to setup-globals
) o7 A( B- K+ ^- [  set current-light nobody ;; just for now, since there are no lights yet
% e) h0 o/ R6 O; r  set phase 09 b; R" x  e% ?( G/ D0 _6 T
  set num-cars-stopped 02 t; p& L1 T) f' I9 \
  set grid-x-inc world-width / grid-size-x
' Y# c1 ~+ K* d1 A; }  set grid-y-inc world-height / grid-size-y8 Y4 ]; P0 [# T  M8 i2 \5 m
+ ?0 A0 ]- ?8 a0 q- Y; Y
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary6 o9 j% N6 V4 \& H
  set acceleration 0.099  F7 |7 c: Z# s
end* `) Q/ U; j6 G2 f$ ^. q

. S( W/ f- O- I& |7 q( \) m6 i;; Make the patches have appropriate colors, set up the roads and intersections agentsets,6 F. M4 L$ H; F' L8 U
;; and initialize the traffic lights to one setting7 P1 c+ K0 c& e8 I8 P
to setup-patches5 m9 m2 F% E, |9 m+ d  t
  ;; initialize the patch-owned variables and color the patches to a base-color
2 j! \% h4 t! _( |  @" r6 C  ask patches
7 r  E* Y; Z5 I$ i, T  [
2 K& ]0 `. H' p3 J  c' r: E/ A1 h    set intersection? false  t8 c0 ?0 D% @+ Z  Z% x
    set auto? false
$ f4 c% f8 n4 j    set green-light-up? true$ t* _: `5 X+ Q) n; n* I3 R. M5 J
    set my-row -1
& M1 b3 g; o: J3 }. [    set my-column -1# [1 U* m$ `- O7 \* P) I3 q% S  J+ ~
    set my-phase -1
/ Z5 P. r9 `8 s1 [' t. W    set pcolor brown + 3
) F1 H9 t! L/ }* h! J  ]; @8 f) c0 W  v3 [! T) c9 ^

8 t7 P, B% P# z* N  Q2 \  ;; initialize the global variables that hold patch agentsets
. M, v0 H3 n; C* Z8 O$ |0 T7 U  set roads patches with
- x; k5 A# u$ }# f    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or! C: @0 ?  i5 b/ C8 q/ h+ f/ T
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]/ P4 _" Q& z5 f* }" l# N. X- I5 b
  set intersections roads with! S: F' |$ i  y; I
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and# [1 a# B, b) Y* @+ |1 E% w
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]" l& y2 w( b- m) J/ ]0 m9 v

3 n5 b: ]$ O% i7 t# n  ask roads [ set pcolor white ], n0 A; {9 J* S% A
    setup-intersections7 {8 c7 a- e' f9 |
end3 Q/ T9 n7 Y9 y% I7 d
其中定义道路的句子,如下所示,是什么意思啊?" U5 f5 ~# \+ C/ [! w' a* ~
set roads patches with
) y" z" w1 A* H1 l! i- S( ~/ h    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or; \8 x2 q( g4 \
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
( |& L# d- |7 P6 O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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