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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。
6 n$ |% g3 ^- Y* snetlogo自带的social science--traffic grid这一例子当中,1 x2 r( o; s5 l
globals
% \/ d; }# m7 K$ v6 O4 z[) R( _( W" C: J$ U) ^  s+ ?: S3 K
  grid-x-inc               ;; the amount of patches in between two roads in the x direction3 }  Q/ f+ M. n" M' l4 l
  grid-y-inc               ;; the amount of patches in between two roads in the y direction
: v1 h2 _9 B. w6 e* y8 ^  M" T5 G  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
( ?. S- i/ p; m( A                           ;; it is to accelerate or decelerate" q* k% D7 d, b) {9 E
  phase                    ;; keeps track of the phase- U/ I' H- V. K- H8 [) z
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure
" F! {0 [  u" K8 l6 P8 D. D  current-light            ;; the currently selected light
) x2 `: @7 }7 K- _
! n5 O, p% j3 {- {& `5 ?6 B, g  ;; patch agentsets2 f% L( C4 p8 g- _. D. G* G
  intersections ;; agentset containing the patches that are intersections
! \5 V* ]" _7 S! `6 M8 H% W  roads         ;; agentset containing the patches that are roads
2 _+ Z* S) O+ Z6 |& ?; W+ C]
4 F, I0 O# M5 q$ c( I; h5 _+ n& r" Z
turtles-own5 r$ x2 g4 F0 U" f  I+ v
[' e/ ]$ X& _7 b& D
  speed     ;; the speed of the turtle6 m. `2 W" T: D
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right  d1 f7 M: {7 H$ @9 _
  wait-time ;; the amount of time since the last time a turtle has moved
/ j5 ~( Z3 P2 R/ i]: ]9 Q5 {. _% w+ Y  T/ a4 L% ^( [! q
5 A1 G' J$ T- Y* l
patches-own
- p' Z$ z3 |9 ~$ W) {) n2 m$ y[! W; _$ y8 x- R9 F' B
  intersection?   ;; true if the patch is at the intersection of two roads: O3 V( l" I8 w6 @0 ?! e5 A& {
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.8 R4 y1 x1 q' v/ c
                  ;; false for a non-intersection patches.5 F* C8 d' v: I' K  J3 ^2 I" E
  my-row          ;; the row of the intersection counting from the upper left corner of the
6 B  ^; K" k6 Q3 N# g" _                  ;; world.  -1 for non-intersection patches.
' [3 g9 ?- ?  N. z7 L5 `; G) y  my-column       ;; the column of the intersection counting from the upper left corner of the
4 _, c3 k& n' p* K, `                  ;; world.  -1 for non-intersection patches.) Z% q" N3 t; ]+ r* U- O
  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
3 c% i. s, ?% }- ]  L& O  auto?           ;; whether or not this intersection will switch automatically.! k  p* @# S( ~1 c% b) h
                  ;; false for non-intersection patches.
9 b$ A. H8 r8 N]8 G9 Q' ^0 u/ |
2 K3 l5 S5 t6 v  ~2 [: h! p/ U
6 v" q: V  o1 ~1 N" o2 u
;;;;;;;;;;;;;;;;;;;;;;6 j% b& i+ z1 |7 A
;; Setup Procedures ;;" K: S6 P2 k1 m% D+ g5 n
;;;;;;;;;;;;;;;;;;;;;;, T/ C, q. s5 j

; k) G+ Y* |( A5 L4 B;; Initialize the display by giving the global and patch variables initial values.# c1 Z  J5 _" e( Z5 ^! o9 U
;; Create num-cars of turtles if there are enough road patches for one turtle to- a# {7 `9 l# l
;; be created per road patch. Set up the plots.. U9 ?3 Z/ [5 x! E$ k
to setup
9 z: R  E) j5 w% a5 l3 u  ca
7 U2 a9 Z" L( U8 U+ b* C6 b5 A  setup-globals
2 C; ?3 M$ c, k) ~1 z& d3 N" b+ ~6 v0 [
  ;; First we ask the patches to draw themselves and set up a few variables" e4 q: R2 ^9 Y6 a  M
  setup-patches
- C+ c% i8 E# }2 ?$ J  make-current one-of intersections
; Z8 F! R9 g5 i" ]  label-current
6 E) N( A1 w7 y% D% x3 ~3 B. v: h7 W, r8 y9 u5 ^
  set-default-shape turtles "car"
, J$ ^! B1 v  L1 }- Q% C7 m0 v8 l
4 B4 j# P8 u- l+ E4 X" `3 X$ L2 k  if (num-cars > count roads)
9 l2 x  u8 T! m& J6 T  `' d9 a  [! H" }; P; r4 @% a  t: U" g
    user-message (word "There are too many cars for the amount of "
7 K8 A5 ~3 d' R. p. F0 W                       "road.  Either increase the amount of roads "5 j# D! t* B  v4 H
                       "by increasing the GRID-SIZE-X or "+ |0 i" a; T4 R# c' r- U
                       "GRID-SIZE-Y sliders, or decrease the "1 |/ @+ V, b5 p9 |
                       "number of cars by lowering the NUMBER slider.\n"
8 ?2 z& E2 C  z, x2 D3 p                       "The setup has stopped.")* b- K& c. h* _
    stop: `7 k: j- s1 d5 K" P
  ]3 ]1 U( J/ o/ H- Q: G# X

2 h- J% g- x1 c: b( }! S  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color! l: H+ ?% ~- R0 O' p7 A$ a
  crt num-cars
) [; L) l9 g5 U) X7 W  [" q" Q! V6 S0 s# V( o% i, y. g! M
    setup-cars3 p  f7 H" E. w) l) ?3 R
    set-car-color, \/ e! K+ _/ a( b+ {2 ?$ f
    record-data* z" c5 T" l$ C/ l; d
  ]
& t, I; a) y" x( V! {3 `6 ?$ B6 A, B  }. C
  ;; give the turtles an initial speed  _$ {5 [5 B; z( ]
  ask turtles [ set-car-speed ]$ T9 l+ a6 H% g8 D
0 a( I! c0 V: V% Q& z5 }' `
  reset-ticks3 J* i! d: a  V. w3 X: k( \0 I- W
end
# m  N! X# z9 v* i( q5 L* {$ E- \% N) U& t( y) E
;; Initialize the global variables to appropriate values2 n2 _3 |+ O+ N. |% M2 \
to setup-globals. y3 ?0 y" Z5 U0 f4 O
  set current-light nobody ;; just for now, since there are no lights yet8 r6 _- A" S0 i9 U
  set phase 0* q: z! t+ R# }$ h$ l2 U
  set num-cars-stopped 0
5 `( b9 K' ?8 N, q1 U/ W  set grid-x-inc world-width / grid-size-x& R, J* M+ I: r% N- _( g* p
  set grid-y-inc world-height / grid-size-y
- L! ~/ U! L$ d7 y, y) U7 G" J. l
- l3 C! {) ~' p! s  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary! J6 P9 u: i% s. B
  set acceleration 0.099  _! x4 a) b- `  e
end
! U, S1 |3 F4 c- Q- z: S% Q: H# `5 W/ ^- I6 Y8 h0 E0 y7 s+ g
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,0 O+ ?' o: }7 B+ t5 U& Y  N9 U5 ]
;; and initialize the traffic lights to one setting- I% Z: w$ B# }$ Y2 a! c
to setup-patches. d7 N7 m8 [% e  D" T8 ?
  ;; initialize the patch-owned variables and color the patches to a base-color: F, X+ q9 d7 Z% X% e5 Z
  ask patches
: `  E2 \1 E6 b5 Q2 R  [
% w( d. h3 z6 Z6 \; E/ \9 O    set intersection? false; g; Z$ [/ O, X* ?8 J- q# l$ E
    set auto? false. F" e) H" Y& A) W. q
    set green-light-up? true% e3 s8 T" U$ v, L
    set my-row -1
' o7 Y6 H2 ^" k) Q    set my-column -18 a* f# Z& {- b7 R3 x& m% a
    set my-phase -1( Q, C& d. T8 b" y# a, }; H$ d
    set pcolor brown + 3: s1 [, \$ f, i* H( X& ?6 p
  ]
0 _6 T) _& [8 L" W" g
+ Z! r/ i1 A. p# l  N. H3 p  ;; initialize the global variables that hold patch agentsets
+ P! a- d4 q8 w+ h4 G# R' u9 c" ]  set roads patches with
1 U4 L7 R' |3 L7 b' [$ |    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or5 S; Y. v( u+ z4 G/ K8 o2 \/ {
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
/ t" [0 ~* C' }+ ~" l% N4 A& w  set intersections roads with: d. v" j3 V# q$ |% ?( X" C2 T2 C* X2 D7 c
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
1 u/ s* u' N; z# Z5 z    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]( U; `& U3 ^, y+ [: X9 c
( J( v& u7 l% B0 q* g; a  q, B+ ~
  ask roads [ set pcolor white ]; O- I( V4 x* C
    setup-intersections  F; l! |: e* i  Y$ E7 z
end
1 j8 m1 j* @) ]- u其中定义道路的句子,如下所示,是什么意思啊?
$ S7 [" T$ ~3 @% d( w set roads patches with& l+ `6 u7 s4 K: s- J
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
1 O- n% d$ u, u8 C: Q    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]# a: _* I& g& w& {
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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