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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。
/ K, \( x1 l9 m# c5 D$ D* O5 ~% lnetlogo自带的social science--traffic grid这一例子当中,
. g8 u, O0 X7 w' N& U; M4 |! Zglobals" N! ^( f, y4 ?$ u" p" t. m
[& \! X) q: b! ?) G2 m
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
# R- C5 ]3 S  j7 ~& Q  X  grid-y-inc               ;; the amount of patches in between two roads in the y direction
4 M6 h# V( W0 m+ |8 P  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
5 ?  q6 ?( R& P: H& l, W                           ;; it is to accelerate or decelerate4 C# f8 I) w9 ~9 X  a
  phase                    ;; keeps track of the phase
" U9 c) \4 p/ _$ k1 m6 r" r& Q: l0 r8 \  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
8 m0 u8 [& z# Q: i; I0 h  current-light            ;; the currently selected light
, B& d$ M1 |' Q% a* J1 x$ F8 o) z1 n: b* s# I
  ;; patch agentsets
. d5 e0 u3 H" a  intersections ;; agentset containing the patches that are intersections: X9 Y4 Y3 ^' G3 b$ r
  roads         ;; agentset containing the patches that are roads
6 p$ o! x) \& \  `% {0 t! v]
" r) z' n4 b. B7 @; g
9 b4 Z) A& w8 x8 fturtles-own
/ I+ ?0 I7 k, [7 U) Q' |[
; K, {' k5 |, D" u2 O# |  speed     ;; the speed of the turtle
! m; W, l3 G* o7 K% a% u$ V+ v8 ~  up-car?   ;; true if the turtle moves downwards and false if it moves to the right( S7 p+ }; r1 Q0 y8 T5 c1 f$ q. v
  wait-time ;; the amount of time since the last time a turtle has moved) R/ S2 U7 H, C/ T+ x7 g' M
]
; T) y' g8 s: I9 G, d5 P7 n. t; c' y3 }7 l: ^
patches-own/ S/ S: Z7 I! w3 c" T# ~+ z. K- Y
[, z3 }# [- v* R, W8 P, X& ^8 F
  intersection?   ;; true if the patch is at the intersection of two roads
$ o4 q) P4 Y. r$ f  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.- C+ G  V$ c4 `, v/ W: E
                  ;; false for a non-intersection patches.
0 m/ U! d' j: Q/ z4 s1 B  my-row          ;; the row of the intersection counting from the upper left corner of the
% ^3 ]: a4 p2 i                  ;; world.  -1 for non-intersection patches.
" J% `0 n1 _. u+ g0 l' v( p$ S  my-column       ;; the column of the intersection counting from the upper left corner of the" h. P5 W* @* Y: k5 U& V4 y8 O4 @: m* m
                  ;; world.  -1 for non-intersection patches.
( _5 n. n. f9 X# z8 Z- k  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.2 v2 ~4 ^% N, l* n
  auto?           ;; whether or not this intersection will switch automatically.; p' L( ^+ c5 H: j* g8 {# X& b& g; X
                  ;; false for non-intersection patches.8 J7 [7 E: ~1 `/ C  ]
]4 ^( f/ U+ A/ c4 ^
, V3 `% U6 o: e3 [/ A" G' u

1 c! x3 H4 N/ ^( J- l1 g;;;;;;;;;;;;;;;;;;;;;;
0 O+ a* o- [6 l  c8 I6 e, y;; Setup Procedures ;;/ t  ?2 g& b: O- O5 R- n, L) v, D2 o
;;;;;;;;;;;;;;;;;;;;;;6 n; n' R0 O( B1 j5 V
8 A9 r+ q+ J, X5 v8 d: L, R
;; Initialize the display by giving the global and patch variables initial values.
. C8 r8 G# `2 `/ \;; Create num-cars of turtles if there are enough road patches for one turtle to& J& f& z; f2 T9 }. _* e
;; be created per road patch. Set up the plots.% g4 L# A& P: Z3 g4 a) g; M; d
to setup
4 N) h( E+ H) Y+ X  ca
8 C- Y! h, X/ W6 x2 }( n- C  setup-globals
8 D$ N1 p2 |) U# x9 p/ D- O7 `
1 b5 I  o9 R1 X$ l+ t3 e* ?  ;; First we ask the patches to draw themselves and set up a few variables
3 t) |  c8 l9 O1 E# ~& o; w; N6 d  setup-patches
5 L6 M+ a2 ]$ x* ~* S  make-current one-of intersections# F9 J+ y- Y0 Y+ C* j# ?
  label-current
, E, t/ l! o4 x4 r9 |5 @  l
' l* \, |% M+ B3 t  {( v  set-default-shape turtles "car"0 D5 H7 I1 m$ m3 c3 r

8 H& l9 L' H. [2 u3 W  if (num-cars > count roads)0 Z9 J6 o( Y  D1 `
  [
* N* H! K9 x$ Y# n' l4 [; z    user-message (word "There are too many cars for the amount of "
. o' v/ V) R3 Y: J5 w5 C+ t( j                       "road.  Either increase the amount of roads "
5 w4 H3 o3 F  Y. ?: d! v                       "by increasing the GRID-SIZE-X or "2 m0 R8 j6 f3 o; @  E4 C
                       "GRID-SIZE-Y sliders, or decrease the "4 I$ ]- w9 K. a) n9 c& N/ l
                       "number of cars by lowering the NUMBER slider.\n"6 |5 T9 [# T# _
                       "The setup has stopped.")# f4 z8 W, v9 Q$ c4 g
    stop
% l  b+ b  U+ E( X( z  ]
4 |4 w9 a" U# ^* H+ ^$ `
- `& s8 H: A  x* |' o0 k9 r  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color, J  c) }  V1 Z2 L- U
  crt num-cars5 @6 s: @! U, u" C# A  L4 D
  [
3 r0 ~6 W$ ]! S: a* k* T    setup-cars' r( @: ~4 U" O% M8 z
    set-car-color# g8 c2 I3 m: t) x1 ]3 m. `4 [
    record-data) X( N; H# V. z! w- V; m* G
  ]
' W  |# N& B- \# }7 [  r' ?2 o! r5 i! V7 `; C% M. ~
  ;; give the turtles an initial speed& C8 x. R, A3 n9 O9 }" F  _
  ask turtles [ set-car-speed ]
- \* h8 i3 Y7 a6 R& b# E' ~3 T7 k, O" r
  reset-ticks
! h% q6 v( e8 k+ L" u" }end8 b- l& P" h3 i: F, V, \+ d6 x
5 c+ s$ k: R' U' x6 Q
;; Initialize the global variables to appropriate values+ ~2 l3 J/ N4 k3 k" U! F9 d) e
to setup-globals
) w2 r$ J; O, K. D8 p) `% G2 _  set current-light nobody ;; just for now, since there are no lights yet7 s/ B7 t7 [4 x( D! n
  set phase 0
8 o, a: Y2 ]0 z  set num-cars-stopped 0
6 `8 ^" G8 g5 }  p/ r* k  set grid-x-inc world-width / grid-size-x
0 ^+ ?' M6 s. e# W( P" ~0 o, c! n9 s  set grid-y-inc world-height / grid-size-y0 E4 H- V, @! n5 [! v" G, B+ I! `( {  T

$ M) E' J0 D; n- Q3 n  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary6 ]/ P" v; r/ ]4 H
  set acceleration 0.099# f; |4 p" H! J! Z$ O, O4 L
end. F( t8 g# _: S; L5 [
6 x$ F7 k+ j% U
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
5 ~: M; q8 K4 M2 O;; and initialize the traffic lights to one setting( ~% c- l- j7 |3 u# n5 U
to setup-patches$ d# b0 v" }, q( B+ p* d! t; T
  ;; initialize the patch-owned variables and color the patches to a base-color; A: ]0 {) _- S0 C% ^- k5 W
  ask patches
, T6 l2 V  H4 E4 q8 h  Y2 W+ E6 S  [
* @/ w- Z: Q6 _3 T6 a6 I  w4 B    set intersection? false: V1 \. R& N, R
    set auto? false
+ ]6 z2 F  u) e( [    set green-light-up? true
& v9 T! N' N% e- S    set my-row -1& ?+ b9 E7 c: U9 Q6 m
    set my-column -1
# `! a4 d8 J& X' D& ~% S  _    set my-phase -1! _0 P: S. ~4 i2 R6 c) G, k
    set pcolor brown + 3. d/ M- g5 V" z2 `9 {/ g. ]( e
  ]# M* G4 v3 E5 g1 @8 ]
& t1 h) |$ k! C* \0 v. _
  ;; initialize the global variables that hold patch agentsets
. B/ d6 M( ~+ V8 l' O) W: F+ L  set roads patches with
, I- e; c7 L) `8 k    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or0 d8 ^* N+ A# P4 W4 x% u
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]& G: o7 z( Q5 V8 J. Q
  set intersections roads with
/ ~0 H+ Q) U/ d$ e    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and- N( E7 E. y1 B
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]( [- b% Q" [/ v4 h. ~9 o

- _3 h0 s6 m% g9 i, f  ask roads [ set pcolor white ]+ W6 }; k0 N7 O4 @) G0 M' ]: V
    setup-intersections& S6 I5 D. F) ]! S2 D% k
end* a6 T6 u3 N3 Y+ w
其中定义道路的句子,如下所示,是什么意思啊?/ ~) w& C3 H  H! ]
set roads patches with- ]! D# k$ V2 E% k1 p+ c
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
, o6 Y0 N7 a4 L" \2 }5 A$ m    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]- F+ k, _1 J; I
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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