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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 d. L& J; k7 p0 S; Z. Tnetlogo自带的social science--traffic grid这一例子当中,; `: M& {6 R, U2 y7 X% {# r
globals
% r; s- u& }( v. T1 T[
+ P) }& T# O1 I7 D2 n& |2 G* `  grid-x-inc               ;; the amount of patches in between two roads in the x direction
: }5 I& T' a9 k  grid-y-inc               ;; the amount of patches in between two roads in the y direction% I* D. `) V' [: O
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if* {: E3 N# j+ h3 ^0 ]& x
                           ;; it is to accelerate or decelerate
1 e8 H! W$ s- L! k: U  phase                    ;; keeps track of the phase
/ q* P2 ]# c; N0 q" M9 ]' {5 t  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
  G: _$ k% W4 y" g, k' l  current-light            ;; the currently selected light6 V  M9 ?& X! x! N% |: h+ n$ A

& [# Z7 q/ ^/ m+ B  ;; patch agentsets
" C1 g* \+ ]# u- A. S; D# w, O2 p5 G  intersections ;; agentset containing the patches that are intersections& |/ F+ G' H3 i  `
  roads         ;; agentset containing the patches that are roads
1 Q# a7 J3 G& r' }2 ^' `]: ~& g/ N6 K3 C: @

' F+ o9 Z5 d3 A1 F7 B; hturtles-own
7 l, A/ W4 n( U* Q! i/ x. g[
& Z( Q1 C9 a- F. M; R/ z  speed     ;; the speed of the turtle
% H7 B; ?9 N5 ]  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
5 L8 E& Z! i4 C* S% P" ^9 B  wait-time ;; the amount of time since the last time a turtle has moved
$ z6 F' g3 Z$ o# L) E]
( ^) s' }  a& I. s+ u9 }2 I0 L
- J2 C2 l9 O: O& @2 V# r$ Bpatches-own7 ~1 f1 k7 A2 H" A( Y
[+ s/ b! M7 ]! V! _2 H0 i
  intersection?   ;; true if the patch is at the intersection of two roads
* m; w- d' x" X) Z1 I  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.! X7 ~4 c9 A1 K2 O6 [& w4 d
                  ;; false for a non-intersection patches.: M) _. C6 Z8 a4 g; C1 Z
  my-row          ;; the row of the intersection counting from the upper left corner of the4 }5 a+ W9 V! C; G
                  ;; world.  -1 for non-intersection patches.
& a# f' w  G2 d, [# E  my-column       ;; the column of the intersection counting from the upper left corner of the9 R$ w9 z2 ~9 q( n- p
                  ;; world.  -1 for non-intersection patches.* O& p1 h' G& ?' C% l7 Y- n
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
' M- Y) N, p/ J* n4 e  auto?           ;; whether or not this intersection will switch automatically.
0 Z$ s: ]- Z( a) I' z                  ;; false for non-intersection patches.$ D; L: O4 u& ]0 f* \
]
) C* I' K: m: X
' J# V& f* I' m/ o9 A9 G4 T0 ^1 W+ z% c1 ~4 k) @; j' o
;;;;;;;;;;;;;;;;;;;;;;' }$ c; j9 A  E% W$ p$ H( W; i& N
;; Setup Procedures ;;) Q% e0 R7 l% I2 z$ r
;;;;;;;;;;;;;;;;;;;;;;
; t& _+ F7 }. L6 M. e6 ~7 ?9 l8 v+ K
  ?' z) v( v$ L7 e;; Initialize the display by giving the global and patch variables initial values.
8 |; {5 H! c" B;; Create num-cars of turtles if there are enough road patches for one turtle to2 I0 r3 }& X0 G4 `' J
;; be created per road patch. Set up the plots.0 R9 y$ U/ _" a1 S
to setup/ x. R6 _# S8 W+ B; w: e8 \7 f
  ca
, g8 T9 q. T: ]" x  setup-globals6 c, s& u2 D/ H0 z1 Y$ K- r7 z0 ^

) ~+ ~- Z& l. r; }9 o1 _+ W  ;; First we ask the patches to draw themselves and set up a few variables/ ?$ E, r4 F3 ]/ `/ [6 I4 X( [
  setup-patches
  [' ~( S9 _, f8 j+ f9 Y  make-current one-of intersections( U, j* m- j2 B; t; i
  label-current
5 V/ \  d( N; U0 W8 `
: G7 M. U9 w3 u5 w4 A5 K8 t  set-default-shape turtles "car"
: w* |1 X! }7 ]3 [" d% O% j& X1 l0 F) a9 s
  if (num-cars > count roads)- k, }% s% e( J+ U" W
  [2 n2 Q* z2 S; r2 z7 \
    user-message (word "There are too many cars for the amount of "
! J- c" ]) @+ Y7 O7 y                       "road.  Either increase the amount of roads "
# ?7 H' i+ r% }6 F                       "by increasing the GRID-SIZE-X or "4 v/ _, t4 b/ ^& A& e  v$ H0 R
                       "GRID-SIZE-Y sliders, or decrease the "
0 P" _4 g1 `3 R6 `5 a$ ^7 Q  v9 `                       "number of cars by lowering the NUMBER slider.\n"
6 H- _: ]! F  I3 {$ \                       "The setup has stopped.")
! F4 a, V7 x1 x+ k. m) A1 V1 _    stop
' U* G2 f, V. e: B8 f. f  ]; o+ D, L7 h# n7 R5 F% d* p
$ i# \; V7 y2 g0 `/ [
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
; ]8 \5 u" l8 w/ M  Z& t8 U  crt num-cars+ E( Z$ j. d0 J3 x% O) N
  [; |' H: d: Y+ H% v
    setup-cars
0 E+ [8 h$ d& k1 c  u( U    set-car-color' @! o; n: D3 z% W# ~# b
    record-data5 ?! L- ^( t# O) M* `/ o
  ]* |" m! @$ I* M0 @

% ~2 B& f0 d1 K! p  ;; give the turtles an initial speed0 e" X9 Y5 ]' @8 p3 J" c' p
  ask turtles [ set-car-speed ]- E- I3 V9 M2 i  C( d
" q! F/ J0 ^/ {* M$ P9 R2 T/ n
  reset-ticks
7 L" k- H! w) ]& b0 j& @end) z) a, S1 R/ F6 q

; r# H! q, g; c4 Z  u;; Initialize the global variables to appropriate values
3 H8 d! i7 q) W  L+ m, yto setup-globals
( F0 L: o/ L1 A2 t; m. V3 y* n  set current-light nobody ;; just for now, since there are no lights yet
0 L6 \/ b: X" x: Z5 {7 T! R* x  set phase 07 \' ]& Y; M& ~: L( r  m' h
  set num-cars-stopped 0
! X- e6 X1 P, Q4 N5 [1 F/ ?5 Y8 v) v4 F  set grid-x-inc world-width / grid-size-x
* M: \, n  L1 }# W  ^9 n  set grid-y-inc world-height / grid-size-y
' j, F! w3 n0 C  S1 a' u8 }& ?7 v  J# S5 H& i6 B( m* @
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
- y: Q' r, m* M/ q, Q  set acceleration 0.099
1 K# o  w: y* G7 `1 n7 M$ ~end
: v: M  G' B, U  d' E) m6 `+ h6 A) H8 Y+ [# O. J" Y/ \# ^
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,& _9 Z  d+ F( u2 w" H
;; and initialize the traffic lights to one setting0 l8 Y( `6 m! K8 s& ]
to setup-patches
/ D+ ]: p8 T5 S# _2 L! P; ^. _$ z  ;; initialize the patch-owned variables and color the patches to a base-color
7 a7 h$ {* p" \' j* Z  ask patches
* L( T# D# V$ a8 j' ~4 e  [
$ x5 Z; _" |* j6 l" u7 r    set intersection? false
% _2 U. h- S+ G# n1 o0 I    set auto? false4 {- ^+ B& Q+ ^
    set green-light-up? true7 j" g. S: n$ |0 ^4 S  y, X1 K$ P
    set my-row -1( u, C0 d9 O0 _5 o; I
    set my-column -14 t  [1 q4 u" w
    set my-phase -1
( ?* V& s9 b9 E3 r) A% e    set pcolor brown + 3
: W! _" X; ^' R8 q4 z  ]( Q( O* E0 m3 m2 B

% j0 h/ v, k* o# L8 O  ;; initialize the global variables that hold patch agentsets
( S4 C6 m. n8 q" N  set roads patches with
6 }( f. s/ l  L2 r    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or0 H: Z, e8 m- w; }' n- M- \' }9 T
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]8 t- ]$ y5 Y; o
  set intersections roads with
( d0 @; C  E7 B! Q, C. F    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and0 B) u  N/ {4 r1 t, T
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
. z+ J$ f. E7 A# E  b
- C0 ?! F, W8 `2 n1 L2 u; y- y  X5 Q% M  ]  ask roads [ set pcolor white ]
7 R7 \# `) W+ f+ W: G6 P    setup-intersections* ~: Z$ M) q+ ?+ a
end
! k4 j7 L1 J5 n4 E, E2 d6 z( @其中定义道路的句子,如下所示,是什么意思啊?
+ C2 t+ k( J& z' W) s5 i) a( Y7 D) W set roads patches with9 y7 v* P3 ]- J: b+ C
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or1 l. `- z7 T# K9 V6 W
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]2 D. e& K+ c# N% j2 P! p  ^
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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