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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。
& |# m4 ]% z4 Y( znetlogo自带的social science--traffic grid这一例子当中,  L2 T9 Z: q" C( U, Q
globals* k! F) |1 b. Z3 ]' a7 d, R5 e
[
+ I: j+ ?' [4 b" w) f1 v8 b  grid-x-inc               ;; the amount of patches in between two roads in the x direction
) g' y/ @& M5 v1 p6 z9 ]4 }7 E/ ^  grid-y-inc               ;; the amount of patches in between two roads in the y direction
% \, v! H3 ]5 a' ?- ?7 |1 ~& E  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
" H: j1 J& Y) n0 p4 t                           ;; it is to accelerate or decelerate) S, n# h) v/ q! d7 A
  phase                    ;; keeps track of the phase
9 @- p9 m  D# u0 U. y& a4 \  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure# K1 N2 X' d7 N  w
  current-light            ;; the currently selected light8 \- L+ A* U- [" {9 v7 I4 e

  l' ?& r5 s2 U+ x+ c- W2 K  ;; patch agentsets7 V  x; a6 n& y0 Y$ X, h
  intersections ;; agentset containing the patches that are intersections
0 I$ Y( L, d2 l) G# Y  Y* J# M  roads         ;; agentset containing the patches that are roads5 |' P, E, W1 T/ D
]
2 \4 h, Z! j( ]1 C
7 |; R5 p9 b- t$ t$ G" o" Hturtles-own4 S: L; Z6 }- c2 @  X  q
[
1 s" ~6 A9 F! f! j9 H  speed     ;; the speed of the turtle5 n# q7 z+ f( X9 |6 A. A
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right. [1 [: E8 n2 _. H2 F
  wait-time ;; the amount of time since the last time a turtle has moved
( n0 [7 q; g* F% b% [/ f' \]0 I) T6 v& L* `3 e* d# {0 B
$ A! n' I# o$ s/ M6 W% j" J2 f
patches-own# j& ?( h0 q2 A3 X# W
[
  O( a; d. u2 I  T2 i  intersection?   ;; true if the patch is at the intersection of two roads3 ?- H5 k! c, s, A: `2 q0 m
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
7 D3 I" n1 V/ M3 C+ o! D" y! B; Y                  ;; false for a non-intersection patches.
; t: i- L4 d) v6 z& f( W8 m  H- K  my-row          ;; the row of the intersection counting from the upper left corner of the
4 m/ `: Z4 e9 K& U, r/ h                  ;; world.  -1 for non-intersection patches.. {' @( V3 v, J& J2 H
  my-column       ;; the column of the intersection counting from the upper left corner of the, }- ^5 ?( E* p, ~4 i, b" d
                  ;; world.  -1 for non-intersection patches.$ e+ H7 n7 ]. a/ F4 K
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.6 s6 i3 t  d2 A) f5 V, y5 U
  auto?           ;; whether or not this intersection will switch automatically.6 T0 C6 t3 a& Z2 ?) t5 |
                  ;; false for non-intersection patches.
$ k( c/ `4 b1 M9 }9 @]
: [6 L5 G4 H/ z* c
, a+ G9 m; a; m- b" ~' t
7 B+ x2 m4 q& ~4 K& w6 }, K;;;;;;;;;;;;;;;;;;;;;;
. w5 r6 ?8 _1 h3 I; P; U" H;; Setup Procedures ;;$ a* q% D6 f! Q  w! ]; j
;;;;;;;;;;;;;;;;;;;;;;9 j* v7 J8 l+ E9 I3 N) U0 q

% Q# j  k- n6 x;; Initialize the display by giving the global and patch variables initial values.
* U* S3 K, T" w" f! [' a;; Create num-cars of turtles if there are enough road patches for one turtle to
# r: `' W0 y# z, ?# v;; be created per road patch. Set up the plots.
, Y1 K# ^6 `8 P4 P( h3 R5 Kto setup/ Z: E" o; q8 c; `1 Z' h
  ca  ?/ ]$ `9 {( z: A
  setup-globals
: S' n1 i5 `: L$ h$ G
" e+ W1 k# d& N% F. p  ;; First we ask the patches to draw themselves and set up a few variables
# d1 u, t2 I! [/ Z4 `' l  setup-patches: W. j6 N7 M4 W5 M' ?
  make-current one-of intersections
+ Z- i+ e" B" ]7 v/ @$ L  E  label-current
6 Q+ L- q! v" r5 |# Z- p) ?
4 ^8 l! K& u. o5 R( o( E  set-default-shape turtles "car"/ [! O. W, s5 y7 E% Y9 p' d

# ^. {" h3 s* y* D* g( a4 w  if (num-cars > count roads)
5 V/ `6 i9 Y! Z  _/ n* R* g9 a6 F  [
- @$ q4 x7 d" e) }/ C    user-message (word "There are too many cars for the amount of "0 H( y+ m  v. n* }9 ?" i# K
                       "road.  Either increase the amount of roads "1 W+ L% z  i* u& a) Q& n
                       "by increasing the GRID-SIZE-X or "
) B' p. Z& C! y: [                       "GRID-SIZE-Y sliders, or decrease the "
9 t8 e9 y6 m; p: n0 n                       "number of cars by lowering the NUMBER slider.\n"
- X! M( q$ Y' P$ O, l( r& i                       "The setup has stopped.")  X+ F* x! F  x- i' Z: Y# I
    stop$ Y' \# d. r7 d. g5 d6 i. V
  ]
( J# O  @, `( f: J: `
9 `% {$ w/ p8 g! t; e: y  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
% H1 b$ j, v$ c' i4 K  crt num-cars
& \( Q4 B1 u: ]: O2 `" t! s) {  [; F" v" P' ]5 @, H9 I" a) `
    setup-cars
' q# t$ Y0 {. }7 q# K5 i1 v& p    set-car-color
  ?- I' m* c' E  f0 ~# t    record-data
" D* H. s7 q' [0 J9 Q$ F2 M$ ]2 |  ]
) t8 v9 k5 J0 b. w8 p9 ]# Z, a( v5 ^7 D5 G
  ;; give the turtles an initial speed
6 ~& f' U$ @) ?$ P# @% f+ `  ask turtles [ set-car-speed ], U; {% N7 n8 v, T8 z

! Z; h+ ]' x0 P, r2 D  reset-ticks
9 v" x! p5 [# g: F% B; Qend6 i6 s/ ~& H& i. `4 Q1 F
: p' A: @/ `3 d; k' T) {
;; Initialize the global variables to appropriate values8 \8 G( g) O; O, Y+ R& o
to setup-globals
& q% X8 B2 q1 z% b  set current-light nobody ;; just for now, since there are no lights yet
# U# M! M6 m" E8 T) Z6 [. w  set phase 0
$ g$ H9 x0 y* g$ U  set num-cars-stopped 0  T/ h8 }8 Z/ A! w' x+ a7 |
  set grid-x-inc world-width / grid-size-x( v# _! a8 y# ?; a! Y
  set grid-y-inc world-height / grid-size-y" u1 ^+ _. L3 l0 Q7 [& `3 X

8 \, B( [$ M& F- f  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary% G. A0 ?" G) D5 p  }) B5 J' N
  set acceleration 0.099$ r% n* j) j, [2 B9 H3 U
end
- v6 C# \  `/ s5 f) }2 U; J
% v. C& D& i% G$ a;; Make the patches have appropriate colors, set up the roads and intersections agentsets,  b; Z, S  g! b& l: F! V: U
;; and initialize the traffic lights to one setting
- n6 R$ {1 N: `& |8 q/ k6 jto setup-patches
  _7 ?" M1 t- |  _3 O  ;; initialize the patch-owned variables and color the patches to a base-color: T( ?: Y; o7 k5 B
  ask patches
( q! _: w5 s& l" s; ^. r  [) w+ P2 p, D; g
    set intersection? false/ c8 t# A+ M1 O: d" k
    set auto? false
2 k' Y( F1 T3 b. Y7 u    set green-light-up? true
$ q4 X/ I1 d3 y3 P; x! H6 Q) s    set my-row -1  N8 {3 Z! p& P5 k
    set my-column -1
! Y% A9 o2 Q5 e1 |2 b. M. a. J8 |% u    set my-phase -16 f2 k7 v8 [" ?( f  F
    set pcolor brown + 3
, D; p. A. h3 }5 ~7 g  ]7 p7 I( c* Y  a# `6 U+ v) G( V0 \
1 a0 K2 n2 k; C  b+ C/ ~9 h' y7 U; I
  ;; initialize the global variables that hold patch agentsets0 J+ _7 e0 ~$ x1 ]* @6 m
  set roads patches with7 [, g& F9 ]3 \" E) S2 b; g) D) {
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
1 D) g9 m' w+ n: k, q    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]1 |% {7 U$ b8 a6 R0 b
  set intersections roads with, R0 H) h* n+ ?
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
0 y5 @) H, |0 h8 N9 E+ V0 s    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
& ]/ D8 y* c- X( O. e# Q& w0 S& f& o
8 D$ [! N1 J* h4 [8 C  ask roads [ set pcolor white ]  c  A  s: u- g0 a6 Z5 `
    setup-intersections
& [* ], a1 v) {, H$ t. {2 ~end* s7 M8 N( N0 |  R/ ~/ c- W5 y1 f
其中定义道路的句子,如下所示,是什么意思啊?
4 e" {% O3 D, W$ ^& e7 e- Q set roads patches with( {, d0 N8 \6 w4 c
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or2 H% R3 b, ~6 I$ m9 }7 O
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
; N3 t/ z9 `1 {+ E8 q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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