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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。
- _8 y  M7 Z+ a- f4 T. h: _, snetlogo自带的social science--traffic grid这一例子当中,
) b& c, t5 Q9 fglobals
* Z* y1 s- `) w) Z[
, s( n( X0 n3 z  grid-x-inc               ;; the amount of patches in between two roads in the x direction
; o  j# @2 C8 V3 O+ W9 {6 C  grid-y-inc               ;; the amount of patches in between two roads in the y direction' c3 j* P) P- A. Y3 ?/ L% ?
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
1 g5 m1 y" F7 N( _                           ;; it is to accelerate or decelerate
' m% d# L6 W+ x* d' }  phase                    ;; keeps track of the phase2 c# e6 A: t5 I& g/ S: l: [0 ]' r5 B
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure1 T! y+ a2 O' g. Y7 v/ a
  current-light            ;; the currently selected light
/ e- K! E8 }. _  W
- E. L2 V! F( F" O  ;; patch agentsets% P3 N7 A- {4 q( `  L6 v+ u
  intersections ;; agentset containing the patches that are intersections. L) E4 V$ T7 ~- N- U. f# X
  roads         ;; agentset containing the patches that are roads
' m6 b8 e3 T- Z2 D! f8 Y]" j& X5 g2 O- c" ?  X. I6 d. ]

4 j1 i: N- a  a+ n/ |, oturtles-own3 w* L4 S6 b2 t! |  ^
[& d+ q2 A  p, ~" r+ T' i, v& x
  speed     ;; the speed of the turtle1 O+ U4 q: l! t4 J6 [8 Q
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right3 `2 U% J% p" Z' q- e( Q  t  t
  wait-time ;; the amount of time since the last time a turtle has moved+ [' Q, v% Q$ y* ^- Z4 {
]! {- j, f1 g6 k

: f) W6 C0 c0 g% d8 cpatches-own
; k/ B) S& ^% @* U  \* l[1 C2 g; P6 g! C. ~. i/ w6 P' c
  intersection?   ;; true if the patch is at the intersection of two roads
5 S* w- \2 M/ l2 u1 i6 N& Y( j  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
) \1 \' Q9 W+ T4 i$ d2 q                  ;; false for a non-intersection patches.1 Z3 f* m7 j0 U$ [) [6 s
  my-row          ;; the row of the intersection counting from the upper left corner of the
# v9 t% ^4 E0 Q; z: f                  ;; world.  -1 for non-intersection patches.
5 {4 `2 N6 t! n+ Z" N$ L/ @5 ^% r  my-column       ;; the column of the intersection counting from the upper left corner of the
+ w9 \" R! L" Y( q! M7 W. N                  ;; world.  -1 for non-intersection patches.# s; }, Q% Z$ N8 Y. s9 k
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.0 K1 H4 I8 U% A$ B; i" N
  auto?           ;; whether or not this intersection will switch automatically.0 ]  i% ?' {' ], t# g9 N9 h' l
                  ;; false for non-intersection patches.. u4 R- y5 C7 a+ u
]5 |5 E: u8 Q. h. x
9 Q& U+ u; ~. s- u/ `2 Z9 U

  Z% Q- f9 T, ?9 B;;;;;;;;;;;;;;;;;;;;;;& U6 {; j9 N7 i. O0 R
;; Setup Procedures ;;
& P3 o& L+ V% m0 l;;;;;;;;;;;;;;;;;;;;;;7 E: g2 E- S" F
& w2 }- B' v) T# ^* `
;; Initialize the display by giving the global and patch variables initial values.* g6 b6 X  Z9 n* c3 o: z
;; Create num-cars of turtles if there are enough road patches for one turtle to
# L- ?: ^; d. p;; be created per road patch. Set up the plots.; y$ Y" R+ [- v& E! G: Q# d0 E
to setup  T/ N# D1 G7 L5 ]" y$ p, A
  ca# S* f1 }% u; @2 B# t3 f
  setup-globals
7 z0 z& K' k/ @
2 ^& e$ v8 a% v: K0 \  ;; First we ask the patches to draw themselves and set up a few variables* U: E$ V2 F* |: U% Q0 D9 b
  setup-patches& D/ T. V1 O- o. A
  make-current one-of intersections
  m' f5 c3 [! q* b  label-current6 o7 I8 l" J' j6 ?0 z
/ L7 V" Y: N3 r4 X
  set-default-shape turtles "car"4 }/ ~- W0 I1 J  k! {5 E
+ v; q( Y% {2 e' q7 y9 |
  if (num-cars > count roads)
6 |3 f" s2 }) r2 N2 G( i  [" i3 P  H: O6 l7 o+ v1 B) q
    user-message (word "There are too many cars for the amount of "
; }6 _$ h  ^$ Q1 ~3 N# Q                       "road.  Either increase the amount of roads "
4 \! D, w4 O8 C& Y  a4 @                       "by increasing the GRID-SIZE-X or "
: x  f  l- V, v* ^) z& E% S- B                       "GRID-SIZE-Y sliders, or decrease the "$ }. n1 H8 O% Z1 j: e
                       "number of cars by lowering the NUMBER slider.\n"
2 J4 S; D- m/ ]( U* r* h' ?& m, {                       "The setup has stopped."); t. T& i# F+ H# b  c6 ~
    stop
6 n. k7 L  K4 F! U) \! e2 @% O  ]# M8 i7 {3 d  U5 U: |# Y: s6 Q

+ ^5 L  f6 @; f* r  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
( G( D$ i& `+ M( I, P  E  crt num-cars3 I0 l4 F6 N# ^9 W7 A7 C
  [3 D( A& N: U4 o5 J' Y
    setup-cars  {- I9 [4 T* L5 L# W
    set-car-color
9 w! o3 S4 @7 A/ ~0 {; }- K% m    record-data+ F' ?. E! X1 p  ?
  ]
9 O3 m$ p9 C, N6 u3 s
0 A+ D" t2 k1 X5 p- W  ;; give the turtles an initial speed; c4 K' m' Z) p3 f/ t
  ask turtles [ set-car-speed ]
) w/ b1 P  {% `! F7 \' e! m+ x2 y0 W4 H  L# h& A2 Y* P# @" g
  reset-ticks
# a+ r! P- P4 L* [, Pend
  E5 j! S1 j' w* U. a9 `: G' Y' ]( Y( m- m8 s& F1 h3 [1 R: m
;; Initialize the global variables to appropriate values8 \) x  \) v% `% d( J0 F
to setup-globals* b/ s0 h2 ?$ q+ o
  set current-light nobody ;; just for now, since there are no lights yet/ j/ Y, @8 D# j( d" Y% s! `, q
  set phase 0/ ]' w, u8 g: u3 M9 R
  set num-cars-stopped 0
: A) c$ R% {8 b( ~' U& n( E  set grid-x-inc world-width / grid-size-x. w- W. ~3 t# R- N
  set grid-y-inc world-height / grid-size-y4 D- u  c6 J. S/ O7 Y
3 {, s5 |; q- U% h( b) X
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary3 m7 ~+ V% e# p$ J  O: \0 E$ |
  set acceleration 0.099; A; d& A8 Y$ z. ~0 S* a4 S; y
end
. X% `" V8 z$ a# R2 |' _
8 n5 W2 e0 ?. O& R& |3 x;; Make the patches have appropriate colors, set up the roads and intersections agentsets,! |5 b6 m) n$ [4 ^) [5 p
;; and initialize the traffic lights to one setting  ^' H$ }+ @! @5 c" ~
to setup-patches
0 e# I7 g, t' F! b; u" j  ;; initialize the patch-owned variables and color the patches to a base-color
' E5 y5 Y* S. [/ b) }3 j' h  ask patches
& w7 b1 K) n9 ^+ S; _/ Q  [
/ y9 |7 J- I% o    set intersection? false
' u) ]' {& a4 q" Z    set auto? false
3 A7 g2 R% t% k. v    set green-light-up? true
* a+ ]3 I, E1 }+ s$ n- k% |/ T    set my-row -1' T8 |+ G4 q5 u( U# E0 _
    set my-column -1
3 e( I) {$ O# S0 b( s9 `( Y    set my-phase -12 g7 S; L" t0 w% i
    set pcolor brown + 3: P) O0 n- w1 n6 ?9 ~8 Y) e, f2 w: |" P
  ]$ ~3 T! D6 \. o! t

, W+ T7 p& B4 }+ d' I  ;; initialize the global variables that hold patch agentsets5 g; r4 m6 H2 F/ j
  set roads patches with
7 i4 m2 q3 ?' |7 t& {    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or. Z# E4 l0 W1 p1 n* \$ ^7 E+ {
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
/ r) Q0 d# @7 Z4 K. A& b  set intersections roads with
3 ~1 Y$ a$ x0 R  T/ G6 ?    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and" w- ?8 H/ m  M
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]- y4 i; d& g3 x4 h

8 d* Y" @) _% [9 l  ask roads [ set pcolor white ]4 X* y" j# m; k3 p& O( ?! |0 g
    setup-intersections
) |* s8 o/ R0 T' H3 ?end8 s  d. S4 S  |2 f5 h( d
其中定义道路的句子,如下所示,是什么意思啊?
5 ]2 {9 G, Y% @ set roads patches with, u! r! V9 }& p, t8 x
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
& P# v+ F; z1 A! s. {7 K    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
: K5 O+ I* G( ~' a# M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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