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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 X4 q. f0 W+ k. z' I2 `+ r) M
netlogo自带的social science--traffic grid这一例子当中,
! o% }" H3 W8 C7 J& M4 gglobals+ C) Q# d$ f( q  }4 h
[
2 G! z5 ]9 {( h2 K2 W/ l& R% L" Z- W  grid-x-inc               ;; the amount of patches in between two roads in the x direction0 p8 T0 ~3 t, N0 P6 I3 [* D
  grid-y-inc               ;; the amount of patches in between two roads in the y direction
, c: {6 ~' p" i" T  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
& o3 o5 k( ]: u& O6 o6 T                           ;; it is to accelerate or decelerate" \. r8 T$ Z4 E. g
  phase                    ;; keeps track of the phase
7 B& V) y  s+ ^& W; Q* N0 |  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
) z6 |" o: y9 o$ L/ u/ @) m; {  current-light            ;; the currently selected light- v. ]9 e. o8 e5 N5 W6 E
+ L  @% S# ^) d$ x: K) H# n: A
  ;; patch agentsets
& c7 f* ^* O% ]9 t$ z2 }  intersections ;; agentset containing the patches that are intersections
2 n& _6 ^0 H# x8 y, h3 i& n  roads         ;; agentset containing the patches that are roads
2 ~6 b& p& q4 {7 F) l: t]
0 F- h& h( ^6 B6 k' x5 C: r) }( f* O3 M( ~, a4 V$ e
turtles-own
$ P/ w7 @* N7 x7 {; q4 F/ K2 W: X& g[3 q. H( U. N7 k; p5 S4 b1 Y
  speed     ;; the speed of the turtle
; E- A0 v7 E* O- N0 A  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
9 v" @8 n# Y7 R0 d" G( j! v  wait-time ;; the amount of time since the last time a turtle has moved
, Y2 ?" W( F1 k]( o) V0 e2 m8 B

& ^7 [1 |3 z. ?" D; H  Xpatches-own
* u& t( M6 h# ]: J) s/ t. x[
7 m+ ?" H* l0 a5 I7 i! T  intersection?   ;; true if the patch is at the intersection of two roads" v. ]7 j6 [6 P1 R5 t$ ]7 L
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
" K6 \9 k  x- V                  ;; false for a non-intersection patches.
4 u1 C! y. C; [1 i; B! J  my-row          ;; the row of the intersection counting from the upper left corner of the
9 f! e7 `2 Z9 O( L+ b! t2 U                  ;; world.  -1 for non-intersection patches.
: v( O+ P8 c" D3 g% ]) w  my-column       ;; the column of the intersection counting from the upper left corner of the
) J7 F5 Z; G% D: t                  ;; world.  -1 for non-intersection patches.- a3 a3 \3 V2 s8 m2 j
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
2 Z  o' q3 k* i5 p  ~, e  auto?           ;; whether or not this intersection will switch automatically.4 `6 `8 L, F. b8 m$ V: J8 V7 B0 V
                  ;; false for non-intersection patches.) S" a- a* {  G4 X. U) O
]
+ U3 r  f- Y' A: h& o& r
+ {7 Y7 E5 G: m0 ?) F8 Q+ u" o+ I' B' i" a* q. ~  \% J7 m- [
;;;;;;;;;;;;;;;;;;;;;;: e6 X1 P1 f6 |0 t  I! Y
;; Setup Procedures ;;
7 M' n' ]8 U7 |1 v. \;;;;;;;;;;;;;;;;;;;;;;
- y, ?# g* ?" x" m9 L6 n7 A% Z' |( ]4 [6 @' t2 C
;; Initialize the display by giving the global and patch variables initial values.
1 o9 w/ s. a% A3 J( U. _/ _! J;; Create num-cars of turtles if there are enough road patches for one turtle to0 i" O, {0 j* P, x5 g6 D
;; be created per road patch. Set up the plots.
: K. \- f* x9 G9 ~4 ^& Vto setup
8 V8 g' ]0 j1 O  ca
% e- C  {& u8 y6 M/ u( r  setup-globals
0 ^8 i, K: w- W- A6 }! @; z4 F7 r6 Q/ f. S7 M% a
  ;; First we ask the patches to draw themselves and set up a few variables
0 a- m5 E8 z0 j; i- O- V7 m; H  setup-patches+ }' F7 Z. }. H, A
  make-current one-of intersections
' y( n* F; D5 f* ^  label-current! M! x( G7 U% b9 @: d
/ O% |0 @3 z  b9 U" [
  set-default-shape turtles "car"  q+ r7 M- u4 Q0 |3 n

9 Y0 l5 ^, J2 u% ~4 @1 _, Y  if (num-cars > count roads)8 F9 M$ S4 a: N7 [
  [7 i+ ^6 ^: L  m, w
    user-message (word "There are too many cars for the amount of "% P  {& k- }* h$ D  }: v
                       "road.  Either increase the amount of roads "
% s1 k1 k& T- k3 ]8 l5 {) n6 R                       "by increasing the GRID-SIZE-X or ". B7 T- ~7 f1 I6 E! U7 ~
                       "GRID-SIZE-Y sliders, or decrease the "
' H2 X" {7 n) S: j( a                       "number of cars by lowering the NUMBER slider.\n"2 w+ N# f- g6 `4 T- P
                       "The setup has stopped.")/ c* g- Z" v6 n
    stop! n' T3 x# W7 ^8 E. |; C
  ]
" h+ d3 I/ w: q: V; {1 m0 N5 M) R6 e+ ]+ b; J- ~8 ~/ A. l7 X
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color2 S& f" c# `3 g6 K8 Q7 u( ?) t  u
  crt num-cars
" B" g2 t- [$ s5 Z  [
  K* ~, Q. K8 ?+ \0 s    setup-cars$ N4 y; v6 W5 c2 |7 B
    set-car-color* @+ u6 [$ M3 B$ P; R
    record-data: _6 `$ C" u- T1 S' @; W0 U
  ]/ x) w+ }$ p! [

" L/ u* F8 x4 Q' u1 {+ {  ;; give the turtles an initial speed
1 ~2 b2 P% _/ ]! `& b! O" n  ask turtles [ set-car-speed ]7 X6 G" J% J: o% x: c

7 z8 F4 ]6 q1 s5 v" s: B  reset-ticks
5 f, I& }1 s$ K" q; O5 c* qend- t  f. f% K! S

7 c) c3 W$ b% S* `& [0 Q;; Initialize the global variables to appropriate values
3 v: t" p5 R7 Q4 ]. eto setup-globals
$ D5 c4 [  i, F+ X% E* x' \% @8 F  set current-light nobody ;; just for now, since there are no lights yet. B! S+ C# M/ `2 O% r3 X
  set phase 0
8 e* @6 t/ @9 W! @& J6 r  set num-cars-stopped 05 m( h3 o5 d& H5 m2 J
  set grid-x-inc world-width / grid-size-x
2 m' H6 E8 p+ m' z  set grid-y-inc world-height / grid-size-y/ y4 W# v+ `; {( u$ [1 k: q
9 F# h: h4 l$ Z/ `7 @. g2 s0 X2 M
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
8 b+ R! w! f* f) a2 R/ _( l  set acceleration 0.0993 ?3 }9 R5 F+ s9 j, N* [
end
) S+ i" x' u; L) Q1 ^; I: u9 `
" q# F  B# F  q9 o& O;; Make the patches have appropriate colors, set up the roads and intersections agentsets,$ e: ]( [4 M5 b2 }/ \  Z. G
;; and initialize the traffic lights to one setting5 U9 [9 T8 L6 ^; o, j
to setup-patches
. \0 N6 G2 ]# Y/ q  ;; initialize the patch-owned variables and color the patches to a base-color0 i5 r( Z# m  L  w  h
  ask patches6 {  G8 W7 b4 b: r1 _
  [8 A  Q: t/ |" {. ~
    set intersection? false
# w7 Q7 A; O, b% y& k    set auto? false
9 m) N  F/ O( [3 c( Q    set green-light-up? true
4 l/ M. c) R2 ]; F    set my-row -1
; W* t8 w5 ^& i) L. h    set my-column -1
- K9 s( k& {( O% J    set my-phase -1* C; i( a! M& v0 x
    set pcolor brown + 3  n3 q& n, ]+ t8 j
  ]
  ^. E+ Y, G  T. _
$ P( ^$ ^4 ~; g, ^  ;; initialize the global variables that hold patch agentsets
6 q* s6 \# y. K: a  set roads patches with4 G, D4 n: N  c
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
4 T# _; p+ B2 r# s; [    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
  D  ^( p( ?/ W  set intersections roads with
# H0 {- U$ ]. C0 B    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
  p( m9 i* c8 a' k# I& ~    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]4 Q5 m# a3 x! N: `" C
8 Z: t# {/ \0 w- ~
  ask roads [ set pcolor white ]
4 k% y1 a9 W3 u- C    setup-intersections
% w# w6 W% \) N: |; w  jend
+ h, I0 b0 F& `5 v* D1 o其中定义道路的句子,如下所示,是什么意思啊?6 z  r9 n) n3 H4 v2 n
set roads patches with; ?4 a( q5 {2 N/ {9 G; T- D; _
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
% R5 W( [; B2 Y7 U    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
+ r$ y0 f; |- M# g: 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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