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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。
5 N, J% m' y+ [4 ^% @netlogo自带的social science--traffic grid这一例子当中,
9 i; k8 ~- r6 aglobals
4 L; i7 h2 m* ~7 P[+ V. i9 w7 N' |9 M4 F
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
8 E8 V* ]" h- V; p  grid-y-inc               ;; the amount of patches in between two roads in the y direction* K& z# X8 a* G+ \' U7 D
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if) N, _9 {' o4 ?( [& L7 A4 A0 i  R3 `
                           ;; it is to accelerate or decelerate
" U! R5 e9 [- _+ R3 Y9 y  phase                    ;; keeps track of the phase9 Q, N: a* U! h
  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure3 D  p$ c! {0 Z& J
  current-light            ;; the currently selected light
0 O0 p& O, U, m' R: m  n
- I" J) M. X" e) k  ;; patch agentsets1 D) {/ U! {! c/ Y6 v2 |
  intersections ;; agentset containing the patches that are intersections
; r/ _! S& Y4 {  roads         ;; agentset containing the patches that are roads: r% Z2 X, A* @! B0 S( O
]
( W' G1 D5 l  c, E5 g
3 W9 B( g6 E) G6 Iturtles-own
/ C% X! V0 w( ?0 f' t8 i; D[0 u2 n" l1 r& F6 P
  speed     ;; the speed of the turtle
4 U( _+ K% p) j# W5 Y# r5 m  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
( G5 l" t, G4 r* j# A9 w  wait-time ;; the amount of time since the last time a turtle has moved* C6 P- Z4 B4 }6 M; Y: i+ X
]5 v1 ]3 D  o6 h) y

- L7 x* [# X! D+ R) L% Gpatches-own/ z% a1 z! F: X- `. k9 [
[
8 Q; M6 ?# {0 l6 I& Q# ]+ v  intersection?   ;; true if the patch is at the intersection of two roads
  Y0 R( i) w$ z' w8 L( |8 e) X4 E  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.4 I( v5 y8 d6 b/ _3 C
                  ;; false for a non-intersection patches.( l; ]$ c7 l4 T7 e# R
  my-row          ;; the row of the intersection counting from the upper left corner of the
+ w0 C, D8 c+ Y3 |% v: e8 u                  ;; world.  -1 for non-intersection patches.
6 r3 q5 x- {. E( K& I  B  my-column       ;; the column of the intersection counting from the upper left corner of the
+ \( I2 V9 F9 y; \) W                  ;; world.  -1 for non-intersection patches.
8 V- G4 i$ u2 z- y  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.
0 f' K! E- j5 x: f3 _5 F" i  auto?           ;; whether or not this intersection will switch automatically.1 O/ E& u0 `/ \# R2 f% e; d
                  ;; false for non-intersection patches.
7 K, {& T4 \$ P( n+ z3 O]
/ x7 n2 z( _0 T
* y' @6 Y4 i: D7 X" z, a  L
0 t. l/ S: [$ I) @' n;;;;;;;;;;;;;;;;;;;;;;" Y# C; A$ ?% T  c, f
;; Setup Procedures ;;& L6 Q  O; A0 Y
;;;;;;;;;;;;;;;;;;;;;;0 G& `1 A6 N2 |" E
; z4 m. L$ g/ C3 A
;; Initialize the display by giving the global and patch variables initial values.  d8 Z: P) R+ ]8 Z1 [
;; Create num-cars of turtles if there are enough road patches for one turtle to# n. P' g+ ]; G8 L. `8 }
;; be created per road patch. Set up the plots.- k5 Z1 W9 Z$ Z& g% z
to setup
- g% M( `$ f: y" E! x  ca
3 E% M0 p! k/ b  setup-globals
5 i4 ]. a* j* w8 Q2 B4 u6 V  \  [; {. r6 \7 p0 O: q. i
  ;; First we ask the patches to draw themselves and set up a few variables
7 x! f" I# b7 ]! F  setup-patches
/ \" q2 t- V1 F3 p, B6 m  make-current one-of intersections
& c6 V1 i' p0 @  o) F8 J  label-current
& v+ y7 I& u3 [
5 N3 \4 R& H: e2 ~$ E: E  set-default-shape turtles "car"
1 A" `8 C' t( u4 _
, c; F) M& y- c  if (num-cars > count roads)
, t5 l. v8 Z* h; V  [
$ D; d  L, d3 D- A  g" ?    user-message (word "There are too many cars for the amount of "/ g' A2 G8 d" r% z6 X) q# K
                       "road.  Either increase the amount of roads "
; b1 ]: d, @$ l/ ?* U3 C, k8 [                       "by increasing the GRID-SIZE-X or "
8 o1 @' U  {& N( K                       "GRID-SIZE-Y sliders, or decrease the "
4 @( D+ ]6 l. n4 k+ z                       "number of cars by lowering the NUMBER slider.\n"
2 J$ \$ j4 O6 A* R0 ^                       "The setup has stopped.")
$ R' k( r+ F5 M7 u! K    stop6 n3 B& d3 u& L0 Q& y& f* S9 ?
  ]
7 `, L3 q1 k2 k9 _$ x# z$ m
3 h$ m- y2 y. s- {: r8 c1 z  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color5 @- O( g5 H8 \2 G/ n/ g( w
  crt num-cars
  R, C2 u7 n* Z6 k4 h. Q* Q  [
/ f& l3 i% N0 \" w+ i    setup-cars" L0 x, L% ~! F" e
    set-car-color
3 V+ }# f  o1 _2 Z6 x$ q* K& J! X    record-data
' T0 p9 `6 U2 |) t4 U5 k: y  ]0 [! a; U0 F# c

! {% k9 d; h7 O0 V/ R) ^  ;; give the turtles an initial speed! [; G1 W; _, X1 U6 _- B
  ask turtles [ set-car-speed ]0 w4 g. A+ I% e; {1 l, y) G
) R; a  k1 C/ b! U4 F  D& f* c& G
  reset-ticks! _2 O" n  |6 j: A
end
9 w0 T" s- O1 ~+ }+ X
/ R# ~: g3 d# j. H! F+ H6 _- @;; Initialize the global variables to appropriate values" E  ^3 |' i' F7 t, m3 N# v: U
to setup-globals
0 t* b2 |7 \0 k3 m6 b% ~  set current-light nobody ;; just for now, since there are no lights yet
' A6 U& H2 d- L8 @- N7 Y  set phase 0
( v- K* v, h  q! k, j  set num-cars-stopped 0- _# ?. n# T; w0 p  {  D1 s+ d* W
  set grid-x-inc world-width / grid-size-x9 S, F2 ~! O$ F: U
  set grid-y-inc world-height / grid-size-y
" l" v' ?4 r0 q5 H/ [' ]0 }- N% i* N9 n$ f! t9 {: R
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary  F( d9 R3 A# g; F5 s! n
  set acceleration 0.099; J2 d. e2 ^4 {1 V
end$ ?( @3 x) Q  @& q7 }* _5 }8 y9 ?
1 h1 l/ @8 }+ g$ F% C  v7 }- }! Y" ^& E
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,  I* [8 h7 h1 ~' A: F
;; and initialize the traffic lights to one setting
. B* M, W, p, x/ E$ L! K3 J# ~$ Oto setup-patches
7 B8 P0 J9 r: N' h2 ^6 \9 e  ;; initialize the patch-owned variables and color the patches to a base-color. X+ o4 i1 h0 t' M0 ~5 d
  ask patches
& t8 f/ a: H; t7 R6 Y" Y  [! a; z" x, i/ D0 U1 Q% m$ F
    set intersection? false
# b3 c) O9 _- |- @0 b* q. {& b3 ]    set auto? false
1 F4 }: P2 w  z6 m6 z. f2 |2 ^    set green-light-up? true
1 f; Z" x% _1 G8 m6 N- \$ I    set my-row -1& K  Z0 P' n& _$ ^
    set my-column -1
: r, A; R$ M( U8 t: q; ^6 Q    set my-phase -1* d' L# E6 j2 W" f- U9 b
    set pcolor brown + 36 e6 h* u7 U( `9 l0 n
  ]/ ?# V- {* P0 D  A8 k
& ^+ }" H2 \( x
  ;; initialize the global variables that hold patch agentsets, }; n/ D+ M. w' d" ~0 U
  set roads patches with
4 f# G# O6 k. z, n- Z1 g/ f    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
# D' ]% ^3 A, n0 {; K    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]3 G7 G, ]0 D1 K- y* v) g
  set intersections roads with; B. p) D' G9 \0 O: O
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and2 B' ^; N1 Q: u! H
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]3 f% W& J1 |5 }1 i( a( C. F9 w

$ {. a1 ^" G# W" N* b  ask roads [ set pcolor white ]* L- g, s  L+ M& X
    setup-intersections
* M& M3 I9 A  A/ [- l# `end- P- c$ ]5 X* q  g2 ~
其中定义道路的句子,如下所示,是什么意思啊?4 Q4 g9 x& G" F2 K/ l: V$ R1 M
set roads patches with5 C7 R6 ?; T9 X) c
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or- c9 i5 f5 V0 C* t% }! S
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]0 T) V) D& k: W, s
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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