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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。: Q5 \5 {; P4 s7 q5 u/ i+ }% c0 [
netlogo自带的social science--traffic grid这一例子当中,1 x* E1 a- F8 r; ^3 y: D$ c; [7 I
globals- b- w( l& Q3 t" o
[
2 |% J  n2 g$ S& @3 W4 U3 v5 {  grid-x-inc               ;; the amount of patches in between two roads in the x direction/ T0 [$ W7 o  u% u, n3 a' h. n
  grid-y-inc               ;; the amount of patches in between two roads in the y direction
: I# p# Y* Y" X; w$ t6 \, D" P' B  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
! ?4 L& z4 }1 ^* K                           ;; it is to accelerate or decelerate
/ L3 m6 D: ~+ x( [* m  phase                    ;; keeps track of the phase
. _+ u1 l" d! U) }9 H9 T# p  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure# z/ K+ Z# T/ w; \- P3 D( ^/ |
  current-light            ;; the currently selected light
3 h+ Z. N& M4 H1 A  ^- R% r( q( _( O9 a: V& [
  ;; patch agentsets, K0 _( }' n" J
  intersections ;; agentset containing the patches that are intersections6 }' w7 z" }, ]# p
  roads         ;; agentset containing the patches that are roads
, x! j$ F3 b6 l7 l]
+ W* N' W. f+ S0 M0 {, g
5 {- |4 [' Z7 R& iturtles-own7 F3 T2 ^% P6 w- f7 m4 }6 @
[
8 Y# u! g6 i; K: b3 i& {* d3 t+ r+ W% M  speed     ;; the speed of the turtle
1 J4 R2 l, T3 Q4 K$ x0 l, Z  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
: d: e; @& X: b. u  d$ B  wait-time ;; the amount of time since the last time a turtle has moved
3 ]7 U& g$ }4 ~5 A9 [# }]
6 f0 r0 B: @( @3 u
* N7 S& e) M2 h. Lpatches-own5 `  Y8 ?4 g& B+ o5 V  Z
[
$ E- v7 M8 v0 `. W( Q' n4 e& N1 s  intersection?   ;; true if the patch is at the intersection of two roads1 {1 |9 J% Q3 E
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
* [) v# w5 V7 e$ N6 f2 T( ?                  ;; false for a non-intersection patches.8 b0 W% y# E. k+ Z3 p
  my-row          ;; the row of the intersection counting from the upper left corner of the+ m! }; W' }# S7 V8 p' n  u
                  ;; world.  -1 for non-intersection patches.
6 \6 f# a- k# Q6 Q% T  my-column       ;; the column of the intersection counting from the upper left corner of the
3 W$ L% \9 _: Z                  ;; world.  -1 for non-intersection patches.
3 \+ O2 H5 a' z) y  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
6 M: J. T" V$ k  auto?           ;; whether or not this intersection will switch automatically.. K: i6 E9 j5 T& W$ b! t, E
                  ;; false for non-intersection patches.
& k: R5 [+ U% K5 \]
# T/ k9 A+ Y) c# C
2 z- @& F9 D! a" G  _) T$ e# a' O8 k' }% {5 ]2 d
;;;;;;;;;;;;;;;;;;;;;;
8 n. q6 z1 ^' ?- q. Z;; Setup Procedures ;;8 k3 b' T, N: v, N/ c3 S; W
;;;;;;;;;;;;;;;;;;;;;;
* w5 g' z  v4 m: V. U
  L# Q& z* F! C% o% B8 Z;; Initialize the display by giving the global and patch variables initial values.0 P: k: `4 i- P% ?
;; Create num-cars of turtles if there are enough road patches for one turtle to8 l+ h' U: E$ h; x( k, S2 t0 Y
;; be created per road patch. Set up the plots.
  t: r  V- v" B, o+ X# kto setup' v4 G) [# R! g
  ca9 M3 B9 N6 v+ x( V4 _- v) ?
  setup-globals
6 a7 A2 h+ B! i" S, D- Y+ w6 m
) Q* V' X. O2 n% P/ y* i% {2 k  ;; First we ask the patches to draw themselves and set up a few variables
# i% {- G' D$ b8 d- n1 A  setup-patches' ]4 J$ b$ |; r
  make-current one-of intersections
/ @0 C% {2 e5 h# t* U: A  label-current
6 y( b% s8 f! F+ m" A* t" t+ K4 |& Y! {! t
  set-default-shape turtles "car"
9 a3 K. _5 D  ^2 m) ~" p+ x4 \, |" [( Y  Q% X1 l; `3 q7 S" r
  if (num-cars > count roads)
. p0 D' @( k8 }1 r$ E5 t  [
+ {" \6 `6 ?/ p) l  b/ e    user-message (word "There are too many cars for the amount of "
6 j2 f& _; Q; l+ P  v0 k                       "road.  Either increase the amount of roads "
/ c0 X5 ]7 L1 a7 p4 u$ c1 Y                       "by increasing the GRID-SIZE-X or "5 r, L- U5 i. [' d
                       "GRID-SIZE-Y sliders, or decrease the "
% O4 U. q0 a% h! e6 C* l                       "number of cars by lowering the NUMBER slider.\n"0 D& K8 z8 y* E4 f, |9 s; Y
                       "The setup has stopped.")3 ~+ `! p$ p: H. M* W8 w
    stop
* r/ F& L) S7 M5 X1 C* ^0 P  ]! Y3 J7 y; e. O8 d! {* `+ k+ Y
, X5 o2 h5 p& X- f! G% u4 @' s0 q2 o
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
( S. ]% F; p9 f7 S  crt num-cars
5 y, U; [( W( |# ?+ o1 N1 F  [
' m! _+ g6 e, E! P+ o    setup-cars9 h: X9 w: R: v# e5 x
    set-car-color2 c6 ~8 s0 U4 K6 h" i
    record-data
% D& `" r$ Y' ]! Z  ]8 L8 }3 c2 O5 g9 C% O, T
0 B3 r, _3 C7 B" z/ O
  ;; give the turtles an initial speed1 b4 y; K! N$ k7 e: k) p4 w( f
  ask turtles [ set-car-speed ]7 g2 [* t/ v$ N
! H" a) i5 S: ^/ J9 T
  reset-ticks
2 c* _# j: i7 J8 R7 @end
0 j( N; J" R2 F- D6 \% ~! d; \, b3 J! Z, k" \6 I; a* v
;; Initialize the global variables to appropriate values
( A" D# }- W& b! c' M& _' pto setup-globals  T: Q* V& d1 K. _$ v5 a
  set current-light nobody ;; just for now, since there are no lights yet
' p2 D. Q+ D* L- Q' g, H. \% C  set phase 0  g9 w) y/ y2 c$ c
  set num-cars-stopped 0
1 q* u# O8 N7 i1 X3 C. d& M  set grid-x-inc world-width / grid-size-x# S! S/ u5 M2 l% r7 `+ i
  set grid-y-inc world-height / grid-size-y
& U% f! K* K0 m6 c8 e8 N! f; D( F# ]2 E: a4 I
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
8 {$ c6 S+ a4 a, u  C  set acceleration 0.0998 @4 g/ Z$ S  H
end: w3 W& a; P, U' W- i
% I; K; H  J3 v3 I/ v
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,3 _0 ~# S; m; f" F4 _" B
;; and initialize the traffic lights to one setting! H8 K. W$ O- i* }" V( e  O, D
to setup-patches% L: T* }9 _5 u' `5 L
  ;; initialize the patch-owned variables and color the patches to a base-color
8 Y  H% m! v' \. B0 F$ G  ask patches
% Z" V5 ~; _  }' N  [  s& j; u# F6 G9 y% U; L( b: s* K8 l
    set intersection? false: G) W8 H2 D/ u8 c0 |
    set auto? false! m2 p! e1 Q* o8 T0 n
    set green-light-up? true
, Z. C' [: _# a    set my-row -1
0 x7 k+ s& F+ Y. h. y0 w; j    set my-column -1
- k% H  N) l" l1 X: ]7 C0 H+ L    set my-phase -1$ K: W- q9 H! ^* x3 L4 X
    set pcolor brown + 3
. }9 O1 M# y( {1 h" P0 \, F9 L  ]
" X3 ]$ b4 h6 B) r: \2 q4 d3 M3 J& I( }. d  o
  ;; initialize the global variables that hold patch agentsets1 D; a8 U, q  D5 c2 K% K, ^  e. k
  set roads patches with+ Y; m, a* a2 e' E! {4 I! Q0 G* m
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or/ _2 G/ B' C5 X( u
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]  f3 b: h8 B9 w& d- s8 Z% ]
  set intersections roads with4 L/ F2 D0 E' Z4 a9 L) n
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and2 _6 @( t& V' I0 A1 B5 d1 ~$ F
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]1 B. j3 k; ~( M: J% W

' c; o3 r7 ~, e, p& w: s  g. B  ask roads [ set pcolor white ]
) L( m/ _) a6 h, B2 _# I    setup-intersections7 k! w+ E2 S3 G9 h( f
end" t+ W# e- Z  o4 h' l! n6 S
其中定义道路的句子,如下所示,是什么意思啊?
! h  |3 z4 q# i8 @0 g! O7 I$ i- n set roads patches with+ y2 H; ?$ l& a) n  W6 Y
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or( w4 d" r7 `; P* N+ f* V/ V
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]4 C$ o9 |9 I7 [) r
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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