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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。4 f; {& X* D: B& T
netlogo自带的social science--traffic grid这一例子当中,5 Y# I2 ?) m: l' V2 @- ?3 D
globals
( t6 n' ]/ x  j/ t% E[" f- ^& e4 y# ~$ d3 Y# \% |  O8 p
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
' ?" J$ z% P( P  grid-y-inc               ;; the amount of patches in between two roads in the y direction
7 _7 t2 V3 r9 U7 ]3 U5 I3 M9 ]3 p  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
" ?+ `* a7 W! q0 D2 x+ D                           ;; it is to accelerate or decelerate& c/ b$ b9 @5 I, D2 i: T; Q, u$ x, [
  phase                    ;; keeps track of the phase
$ e; G6 j  ?, n3 j/ ]) Q, E  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure' ?; z% p7 U' l; d0 L
  current-light            ;; the currently selected light  N0 _" c4 g8 B! M: }8 C2 ^; I
: z$ i! |& b$ J+ w4 T" g; h: Q
  ;; patch agentsets
2 Y, ~; l% a( \7 U& ?  intersections ;; agentset containing the patches that are intersections
2 z, u& ]" x! i5 ^5 R9 C  roads         ;; agentset containing the patches that are roads
  L& x, U0 [( E]1 f1 ?2 Q1 p1 c' b

7 E1 A2 v' O- D; }: t6 m  _turtles-own
. B6 _- u3 @, a6 e+ b% h/ q8 A[
. V  O( E+ P4 I, Z& r" _2 l8 t  speed     ;; the speed of the turtle
. K0 Q- A* u- _  D  up-car?   ;; true if the turtle moves downwards and false if it moves to the right- j1 A4 o/ J1 f3 ^# ]8 l
  wait-time ;; the amount of time since the last time a turtle has moved
  v3 {* x. u7 c1 H. o7 T) ]]0 D' F' ^  a/ i/ [. X

1 ^0 ?! t, M  d% K! Tpatches-own
3 k* j  X5 e3 w- r[
5 `0 V- J* y1 U% d6 q! U  intersection?   ;; true if the patch is at the intersection of two roads9 D$ m) @0 \  @# I6 d
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
  y$ g7 f* h. _& f+ D+ }; h+ ^$ z                  ;; false for a non-intersection patches.
; V) i) f2 i9 l$ r' j6 o6 n+ [  my-row          ;; the row of the intersection counting from the upper left corner of the6 t9 U! B' s/ C- X% f- J
                  ;; world.  -1 for non-intersection patches.0 S) j9 E$ U% N
  my-column       ;; the column of the intersection counting from the upper left corner of the
. \9 K+ J* z+ y6 ^* G+ f                  ;; world.  -1 for non-intersection patches.  p1 l8 w( I$ _, {" I% J( T5 L* e
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
/ k# J. [3 }- j  auto?           ;; whether or not this intersection will switch automatically.$ E; y# j0 N# x. x# y; t# ~
                  ;; false for non-intersection patches.. M. K5 A; o5 l% p1 c1 N/ N
]4 ]; J% @: V8 ?$ m8 _  w/ a& j
1 b3 T$ ]! j5 _0 Q* A
1 T, f& K( a9 n8 s+ N8 v3 d
;;;;;;;;;;;;;;;;;;;;;;, n, u6 Q8 X: ?9 T6 E$ b4 g
;; Setup Procedures ;;
( G& {9 _* ^, k0 _. D6 E) x) V' C;;;;;;;;;;;;;;;;;;;;;;+ z+ x+ o; i7 T7 m

) L4 C, Q2 @) L, K; p0 c) q: u" z;; Initialize the display by giving the global and patch variables initial values.
4 Y( F1 Y' N; o9 {) t& A;; Create num-cars of turtles if there are enough road patches for one turtle to3 U$ q1 C7 r  t; T, b0 s/ J- q
;; be created per road patch. Set up the plots.4 C! ?5 f3 p( d) T) A
to setup  R* B1 C  [7 \
  ca
3 r0 d, p9 v' i. V  setup-globals
+ V, G& `0 K# F9 d  ^  ~% X
# `' A- z/ i$ {$ j  ;; First we ask the patches to draw themselves and set up a few variables! E) I  A: G/ O1 P
  setup-patches0 W( |# B& T7 N$ D: K# I5 L6 y) b8 z
  make-current one-of intersections) \( v( r& `; b/ r# A6 t
  label-current
9 D! @1 r+ D$ Y! n5 n$ ]7 Q5 L; l) \* j6 R( q: I
  set-default-shape turtles "car"
6 p2 G2 {( H1 u. Y( ]: E4 s, U' Y: ?" j
  if (num-cars > count roads): R4 {6 Y5 n/ f; I
  [
/ i7 N/ p2 Z! [: s0 C) U1 m4 T    user-message (word "There are too many cars for the amount of "1 O8 \% T% h3 J
                       "road.  Either increase the amount of roads "$ P$ L1 j- X& K$ U, P' J
                       "by increasing the GRID-SIZE-X or "5 k8 m# y' g3 T5 u
                       "GRID-SIZE-Y sliders, or decrease the "
% U: w" z: Y& o9 G' y/ I' Z' X9 E                       "number of cars by lowering the NUMBER slider.\n"
" [9 l/ @' J8 P: |8 D3 h: N! o) w                       "The setup has stopped.")8 b! u6 R, ]% {' [
    stop: Q6 ~" K: T1 i" r  R
  ]
7 ^+ C8 L3 K. f$ J' E4 ^. F/ I
6 C1 }* V8 j( |  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color4 B4 ]7 B9 _( i. {( g* H* O
  crt num-cars
' l4 P; c5 Z" F  [1 ~2 U( f) U9 w4 B% f/ j
    setup-cars
5 @4 v; Z' H# {0 ]    set-car-color* h0 m  W0 T+ ^0 ^) u, @- U  h; y
    record-data
! l% O# V& X! p# ~6 L  ]
7 {% q* R; h* g; U6 N% E1 k% j* B3 \( @2 Y
  ;; give the turtles an initial speed& w0 \/ J* G- T0 P
  ask turtles [ set-car-speed ]
- c# f# W' G  v& N9 P* F& t: i3 \% q. d$ A: }! i
  reset-ticks0 }  x( ~7 `  t6 O7 W$ b
end! s* y8 k) }$ r+ A& X. s

( O$ a: k* X% r;; Initialize the global variables to appropriate values
# j. ^6 \* D8 j# Fto setup-globals
% o5 d0 K* L6 O  set current-light nobody ;; just for now, since there are no lights yet3 t# V6 G4 ?- U; e# [9 o0 D: C
  set phase 0: e; z1 ~) O& X, M: `
  set num-cars-stopped 0/ L, o- q. _, E5 A! p: X" ?6 O
  set grid-x-inc world-width / grid-size-x5 s" U3 K2 @, r
  set grid-y-inc world-height / grid-size-y1 g7 p- [6 O( I% Y

& w& R2 }( `7 d- N: O  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
7 e8 Q1 Z' w) Y+ P8 p& Z! z8 Z  set acceleration 0.0993 ]6 W( ]: e* {5 m1 w# z3 k. V
end
3 i; A6 Y1 `  w. u) s
3 A5 A1 S; f+ i7 z/ F+ u;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
8 z0 ], M/ B( s% `! b;; and initialize the traffic lights to one setting
2 A$ i4 e+ e* B' ^2 {  Rto setup-patches
6 N0 x+ K  V; |& {' I  ;; initialize the patch-owned variables and color the patches to a base-color
8 P: s! c" L1 p  ask patches
3 G/ o) c) H4 v  i0 x$ G3 v1 U  [
8 P! F! |4 N( p, |! o  J    set intersection? false1 R8 U6 j  N( J6 [% @; j6 V
    set auto? false6 a$ w# H8 d$ {- t
    set green-light-up? true/ L% x+ @! ~# `  Q
    set my-row -1
; I( V$ c8 \5 K5 `  d2 q) N  f    set my-column -1( }0 W" w1 p/ \8 P. X
    set my-phase -1: N1 v# ]4 Y% {# w
    set pcolor brown + 3
$ K+ y; c% l) s6 `  ]/ w( C* E$ ?2 Q

7 V' U% t# N% e  K) N+ e! ^1 x  ;; initialize the global variables that hold patch agentsets
1 N/ j* i$ y$ \$ S6 A# O  set roads patches with
& y, M2 t' _! T$ \- V    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or- Z: e! [: H" C* N' \
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]7 J9 O! Y; o0 m/ ?0 s* b0 ]
  set intersections roads with
! ~5 T) {; |+ {/ m) U    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
# M3 Q* o0 w3 b7 q' ^    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]5 q( N# l5 X0 ^- _" S
" u' ~1 W! A; ^' f  Z
  ask roads [ set pcolor white ]$ P' _8 M3 ?! x, t) m( @8 ?9 b
    setup-intersections
1 M0 v5 z4 ^: F/ C7 j6 lend
* b9 @, \( a& P4 s2 f6 V( v其中定义道路的句子,如下所示,是什么意思啊?9 b8 s' G* ]: L- _1 F* e/ F3 P! Y
set roads patches with
; }) @; U1 Y, x. R) r4 x& p    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or7 R. Q- P8 @: Q0 c' \9 j
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]) ?' X5 h. c1 Y' R, g- r1 o9 z
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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