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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。- A) N* ^; P8 O' g8 q$ ~7 e
netlogo自带的social science--traffic grid这一例子当中,6 i1 M! L9 O* i! I% `: c+ d
globals
5 T; i3 M! q: b2 f[! ^; a9 z5 ?9 e# U- T# R
  grid-x-inc               ;; the amount of patches in between two roads in the x direction
, C2 d  ]7 B1 E& J# o2 B8 M  grid-y-inc               ;; the amount of patches in between two roads in the y direction
8 v6 I# ]  y, [% a  acceleration             ;; the constant that controls how much a car speeds up or slows down by if
, w& R5 E; y# U; j6 j                           ;; it is to accelerate or decelerate
" z% W; t8 d! l; S) `. @9 H  phase                    ;; keeps track of the phase
' _3 c0 z/ z! W* d  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure- G; |' ~' y8 a. D& c
  current-light            ;; the currently selected light/ C8 P' t6 R2 Z! _# F! a

5 Q5 c: D: ]1 U7 P* ~  ;; patch agentsets& q% e6 h( a' [8 i' n1 b! ~
  intersections ;; agentset containing the patches that are intersections
1 z" X4 r+ L/ s: K; G. ]- Q/ y, [  roads         ;; agentset containing the patches that are roads
+ I: A) U) R( t: z; d6 B! []  U( C2 Y9 X6 K5 @. G( E* Z" j, }

+ H7 B* w  s. @2 ?) a: o7 Xturtles-own
: a3 T' h+ C$ ?0 u& z& b3 Y0 V[
2 M2 q* k5 A6 f6 d* A9 S  speed     ;; the speed of the turtle
$ ^: A4 {7 s- l/ [% f3 W* i  v+ K  up-car?   ;; true if the turtle moves downwards and false if it moves to the right3 |0 q% L" n* k( B7 O
  wait-time ;; the amount of time since the last time a turtle has moved
, P# {5 u' G& V# V7 a* V]
. L" o7 ?# E  q3 F, W& {& p# D+ {: `% V& l1 l' M3 U6 \
patches-own
  l9 F0 h, L: ?: p7 A( y8 A* @$ l[
6 y' R8 e# M' P  intersection?   ;; true if the patch is at the intersection of two roads6 ~, Y0 J1 t3 R! p+ M) H$ T
  green-light-up? ;; true if the green light is above the intersection.  otherwise, false.
" M/ [2 u. D7 H) w5 w                  ;; false for a non-intersection patches.
: x$ F1 h7 Z7 v0 \, u  my-row          ;; the row of the intersection counting from the upper left corner of the
' O& u6 ]7 \, I$ _% g, z8 |% Y1 E                  ;; world.  -1 for non-intersection patches.$ A" X2 s! J* X: g
  my-column       ;; the column of the intersection counting from the upper left corner of the
% q! F0 Q6 L) {% i  E7 S1 v                  ;; world.  -1 for non-intersection patches.
( O! f4 `9 n, s& B& A  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.6 O+ [; v9 H: f+ u4 X
  auto?           ;; whether or not this intersection will switch automatically.
  p3 y0 h1 c3 q8 T                  ;; false for non-intersection patches.
$ }7 Z2 J9 y6 `& O. G) V2 _8 h]) u$ D2 t, t: M  d; U( ~$ o+ o8 g. Q

/ ]4 I2 d1 [. D; l1 I$ V' z( T6 H/ {
  u' a& ]! x  d1 E$ p;;;;;;;;;;;;;;;;;;;;;;
; Z% [$ Z" F  W1 W;; Setup Procedures ;;
: ~  e# M+ P" n6 W# [;;;;;;;;;;;;;;;;;;;;;;- i- y2 \) K3 i" v/ I9 n; Y+ F& S
. Z% F3 g9 {, V; d8 E( b, f
;; Initialize the display by giving the global and patch variables initial values.
5 ]* O/ X9 k0 h6 a+ L! O: @4 z;; Create num-cars of turtles if there are enough road patches for one turtle to
, ^4 U: I7 m' H; F9 t$ F8 R' f% T4 I;; be created per road patch. Set up the plots.1 A) B6 g6 N/ {( b( }, p
to setup" s/ K1 _) {# Y$ r8 C9 V, w8 X# |
  ca) y' S) G8 s* ?
  setup-globals9 k1 @" t- @2 z. l& y  `  c

( n- L. y/ ^' T2 W( {) E  ;; First we ask the patches to draw themselves and set up a few variables
" ^( H1 s7 _- X: u  setup-patches
5 c4 w5 D) X. [$ Z  make-current one-of intersections
3 B7 [* ?, ~8 v  label-current
) J: _% I$ O* M7 x0 A) P. @1 H% p1 m) c: D( }5 F% M) b
  set-default-shape turtles "car"
$ a# ]& G: A+ ^" X2 ]
( y# ~( [- F! o! q  if (num-cars > count roads)+ o& E/ t5 H+ P. L
  [
& T* r! L$ e( N+ o2 M+ X8 `    user-message (word "There are too many cars for the amount of "5 h7 p4 e& P6 B+ @5 d# k
                       "road.  Either increase the amount of roads "
4 T6 a+ w# N5 z/ X( ~5 \                       "by increasing the GRID-SIZE-X or "9 ]8 [3 W, y' J: u! }7 w. {# D
                       "GRID-SIZE-Y sliders, or decrease the "% b0 j& @2 ]' G% C4 O
                       "number of cars by lowering the NUMBER slider.\n"
% a( j; f1 [" v0 V5 c4 G                       "The setup has stopped.")
5 {; s" ^( W* O9 N# J; l" X    stop( C# }, u2 Z; D1 }; l" P& H
  ]
: {9 B1 w/ D- G  T) k( j% o' t: @6 _/ U, |
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color( W! k7 _3 V3 m8 u4 ^
  crt num-cars. I& Y4 d7 d8 w; S9 E! a1 B
  [
) i" X, ^$ J# [* |/ n# `    setup-cars: v- |9 Y. L9 s9 e, X( J$ |5 `; o
    set-car-color0 j  o) X* I9 Y
    record-data
! p; r0 y2 |8 {7 D9 y- R/ g  ]
' V2 a& _9 N/ O% A( {5 r% d) z* X0 {4 I9 u4 A. n' O
  ;; give the turtles an initial speed
8 {! N+ F9 }2 R1 F  ask turtles [ set-car-speed ]
, b& g: T2 k% q$ s- H
/ r+ f" q. M: O  reset-ticks
' D1 k" P+ [7 \( n! [5 E# H7 G3 Iend
; C, V% S3 t  n0 k9 i$ Q# y0 b* l- o: x2 x' U3 _4 L
;; Initialize the global variables to appropriate values
5 Q) @% R- }9 o3 N$ D8 t' [/ n# F% Dto setup-globals3 n0 p+ a# v/ F+ j' W
  set current-light nobody ;; just for now, since there are no lights yet* K3 _2 _$ J  [0 m
  set phase 06 U  N- h) P6 J1 C- J
  set num-cars-stopped 0
0 w4 r: `+ s3 z  set grid-x-inc world-width / grid-size-x" n- X! B8 d" D/ V- ?
  set grid-y-inc world-height / grid-size-y
- ~& P$ x* X% i: `4 i" v6 [7 v: v5 h) }2 S4 S4 W
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
; s3 T0 h, ]$ w  set acceleration 0.099
. O. l+ z4 Z: S8 Wend; W8 k9 O7 i2 r+ {# n
7 V* j/ ^. i& [$ v6 O2 J
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
- Z0 b' N3 B9 W/ v! B;; and initialize the traffic lights to one setting# A% V8 F2 ]" o/ u
to setup-patches4 R) }* Z: h) E
  ;; initialize the patch-owned variables and color the patches to a base-color) D' s; J% `; c
  ask patches
  Y) P( Z/ W* o8 }  [
) F4 }4 Z/ l! P' m, ~9 L5 _6 j, D    set intersection? false
! l! }) E' {$ f* N4 D    set auto? false
) B0 w# Q* L8 ~- a" p- c    set green-light-up? true: e0 x9 N& m$ B6 v& c
    set my-row -1) G" z* q6 ~; ^! u) p" W
    set my-column -1* q) O# O( e/ X% y* o
    set my-phase -1: w$ l2 F, t4 U% x' p
    set pcolor brown + 3  H4 \! F0 C1 o. y
  ]
& Y' [% o% v5 {+ U
/ k) g& U2 H8 o: B* ^+ b  ;; initialize the global variables that hold patch agentsets
2 l% Z) q# I4 S+ l5 L- @1 Y) u  set roads patches with
! Q1 c6 j# @9 f7 G9 E( Y, a+ O; P    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or& F, f3 k0 V7 t1 T: n, G
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]6 p6 u! Q* E4 H5 O/ v$ `: S" _
  set intersections roads with1 u9 l, I$ ?& g9 b. `7 I1 s
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
# r" Q# f: B: |- X* Y    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]: ]. Q$ a8 D8 H% u- q  \% n! ^+ L) o

' b9 p" B( \0 A: U' B  ask roads [ set pcolor white ]
  V9 P8 j8 q% a* i    setup-intersections
6 f" n  _: i7 n* e9 ?end
+ b: f, g. E6 P; H' M: O其中定义道路的句子,如下所示,是什么意思啊?0 Z( P4 c8 B0 Q; g3 p7 T
set roads patches with
1 m' j% y0 _/ `/ i% D4 w0 F, T    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
* B. ]6 F, F' J" R! e6 C8 F    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]: `$ N+ v: w1 t( A2 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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