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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。3 N8 g; v9 {, @3 s/ Q9 d
netlogo自带的social science--traffic grid这一例子当中,* N1 r" c% W/ i& t
globals/ b, J3 _1 s. ]: D& M- K" y
[; h% M9 I; s5 d5 A
  grid-x-inc               ;; the amount of patches in between two roads in the x direction9 ?9 P2 v0 s7 B0 i7 C; p8 }
  grid-y-inc               ;; the amount of patches in between two roads in the y direction1 `/ H+ }" C( e
  acceleration             ;; the constant that controls how much a car speeds up or slows down by if1 v5 w2 z1 I! {+ L
                           ;; it is to accelerate or decelerate
2 m& O8 Y. x0 G) o  phase                    ;; keeps track of the phase
. E7 h7 D, T5 {2 W0 `  num-cars-stopped         ;; the number of cars that are stopped during a single pass thru the go procedure. `2 K0 Q! s& W, I/ R
  current-light            ;; the currently selected light
/ G* ~+ a2 O8 Z; i* a2 U! @5 }1 j) o9 b' Z- n) W/ F7 u: D' q3 N; b
  ;; patch agentsets
5 v# H; @2 R" t% V  intersections ;; agentset containing the patches that are intersections
* D. R) {' Z$ o. r5 o  roads         ;; agentset containing the patches that are roads
  \5 n6 H: {  s]
. h# p  V# i0 H: W
3 p8 k6 T* Z- {" g# ]& Wturtles-own& J  K" i# c3 C+ O* F
[
% x3 E) r* Z% ^/ K  speed     ;; the speed of the turtle1 X, }, v% a- N  S9 O( \
  up-car?   ;; true if the turtle moves downwards and false if it moves to the right
& k+ r6 D; A# x! z" R) B$ _  wait-time ;; the amount of time since the last time a turtle has moved
3 U% X; P5 ^/ @4 A$ R$ b]- n4 C" ?2 ]" D7 S$ o+ T' |

3 n; F1 j. G6 A+ ppatches-own
) G1 t* }2 s( b' K0 f4 G: j2 |[4 O$ f' @8 Y$ q6 ~8 v* q1 O& m
  intersection?   ;; true if the patch is at the intersection of two roads
# Q1 ~# n  n( r; {: n  green-light-up? ;; true if the green light is above the intersection.  otherwise, false." F) h# j" R4 y6 a# U- ]% G
                  ;; false for a non-intersection patches.
. _+ f0 d$ [$ `; h& m; D6 L" b' A  my-row          ;; the row of the intersection counting from the upper left corner of the
0 X( T" O/ m# P, `: V# a                  ;; world.  -1 for non-intersection patches.2 \; `$ l" f% N7 u# E* l! F
  my-column       ;; the column of the intersection counting from the upper left corner of the
2 L7 b; u$ Z1 \- i0 `                  ;; world.  -1 for non-intersection patches.
5 E) ?3 o4 Q! D; o  my-phase        ;; the phase for the intersection.  -1 for non-intersection patches.5 N; d7 H$ v+ Y- h' X1 A
  auto?           ;; whether or not this intersection will switch automatically.& \& ~) [6 c/ @% `
                  ;; false for non-intersection patches.
; ?/ r( P1 u6 Z]  O& c- U/ S# ^& c! A

, q/ q( r/ j; f" h- U( Y7 W5 |: Z: c+ B9 u
;;;;;;;;;;;;;;;;;;;;;;
+ I5 {3 [, i3 I3 }1 B5 F& X4 f: x;; Setup Procedures ;;" E! i# I- C/ _! t' `+ @" A; q
;;;;;;;;;;;;;;;;;;;;;;
0 h* O. P3 X5 T5 `4 k' P. T+ C7 w* \+ b! j2 Q- M' G
;; Initialize the display by giving the global and patch variables initial values.0 X0 V5 }+ k( s8 R9 X
;; Create num-cars of turtles if there are enough road patches for one turtle to
/ N  r1 m, B5 r5 i# [; C  r;; be created per road patch. Set up the plots.1 Q, q8 V  b. I0 N/ M' l: G3 Z
to setup4 v' d! v" u7 L# R
  ca, {- y! z8 c) Z1 z3 P
  setup-globals
% D# q) Q* p/ G9 N  y/ R' r
4 [: i" j, C. _5 K  ;; First we ask the patches to draw themselves and set up a few variables  w+ F9 X! |5 }  b& I; G
  setup-patches  @3 V, z1 L5 N# m* A
  make-current one-of intersections( q4 s4 p: N6 N( @' g% }) @$ o0 Y) w
  label-current
4 x/ s1 q5 q# w5 ^* ]: y/ W7 w( r2 [) X4 `
  set-default-shape turtles "car"1 `7 J& v5 S1 e* t9 Y/ S

# m+ [7 i# X2 I9 O) a! Q  if (num-cars > count roads)
9 v5 Z# K; b) C. k) ~# l  b3 J  [
' h$ h# e1 k/ c& J    user-message (word "There are too many cars for the amount of "6 ]' h. v. u, Q% m/ N. i; I" v
                       "road.  Either increase the amount of roads "" E( z  x4 d$ H0 P+ ]% O
                       "by increasing the GRID-SIZE-X or "* O! H  s9 y5 r0 D& E
                       "GRID-SIZE-Y sliders, or decrease the "' S" h& [2 x3 _- |# ?2 ^  \
                       "number of cars by lowering the NUMBER slider.\n"
) T- `$ m: z& ~# A, g( U9 g                       "The setup has stopped.")
& L" `# `; }$ O1 A3 ^  c    stop0 j. ^! @+ w& P
  ]2 @/ ^% V2 O3 C5 A
5 t& i) r0 T. m* i
  ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
8 H* e/ o3 a2 I  crt num-cars/ T. m+ y6 G, y# v. b+ n9 \
  [: I, n6 j& E& {& Y! J
    setup-cars
- i. b# k6 h3 ~- W& h; j' ?    set-car-color
# A2 G* G+ x' d  H; N4 {; q    record-data
  c0 f1 x) X7 C- `4 i5 t1 w: \  ]
1 q7 O3 N( K" `5 e' H: l  y/ ~: n( i5 G1 ^
  ;; give the turtles an initial speed& O" {2 X" n8 K6 n* z3 s! e
  ask turtles [ set-car-speed ]0 k  _# v% g' B8 F7 p
; J# D& N6 V' `, g: Q
  reset-ticks
" v" r. M' p7 rend
( f  r8 q5 F7 g' a0 B7 l/ K+ A7 r! n2 l! l
;; Initialize the global variables to appropriate values$ X1 F+ o  U; J' J, D2 _# }8 K
to setup-globals
( [* `  ~2 }8 M% x  set current-light nobody ;; just for now, since there are no lights yet4 Z# Z- c3 [. J/ H& t' c& {) x
  set phase 05 Z" f& g: m8 N$ m' j( z
  set num-cars-stopped 0% U; M6 r( z) e) \$ B# @( f
  set grid-x-inc world-width / grid-size-x: E% H7 n' K; e- w5 u# ^  o8 A' Y) j. z
  set grid-y-inc world-height / grid-size-y
8 P) E  \7 Y% E1 b' U7 |; F6 J, S; T+ Q' P0 N; l9 g) x3 q2 v
  ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
$ F3 a% w% a* {1 ?. U9 o2 W. T  set acceleration 0.099
: E" K- y, w, h5 |end
: o4 B) @  [, b- m* @! \8 n% N% x) N+ ]4 K( S9 W* Y9 r* Q) W0 y
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
- x, {9 u$ s- F( m0 f. f8 F" g2 D;; and initialize the traffic lights to one setting- G" `5 C$ U8 Z# h! e. i* v3 I) z! |6 \
to setup-patches
6 T/ s. _; i3 z2 @! @( k  ;; initialize the patch-owned variables and color the patches to a base-color
& Y* G) \  }- _  ask patches
) g4 z$ |. W1 i7 {- X8 _$ L  [+ u0 ?! d/ H, C5 n
    set intersection? false+ q! i3 B0 r9 {% l# P
    set auto? false
/ |. \3 i) c- J7 b/ ~$ K8 y5 e) X4 d    set green-light-up? true
' p1 L' Q/ c  r7 o3 C& u% ]0 D    set my-row -10 x/ W& S2 T  X9 ]( ~# j7 m+ u( s! j1 @
    set my-column -1# W9 x; l" J0 t( x# y" A5 A9 r) R
    set my-phase -1
& i5 Y7 j9 s( ]3 V1 P    set pcolor brown + 3' e9 C: w0 |( C, R$ D* |* V$ O
  ]
1 x  R- y7 r" u0 o
' C' g0 \/ q* t1 \  ;; initialize the global variables that hold patch agentsets4 r( i5 B" W( S0 y, ^
  set roads patches with6 @6 W# I+ B) z: g$ @' m0 r2 ~
    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
! _9 w- Q5 }7 `: c$ u    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
1 [5 z2 N5 W) F+ _+ U/ ]& D. u  set intersections roads with
% p2 I. }3 W8 S$ a, \    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and! j( v% v1 p" P9 a
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
2 T7 L/ y. E1 @9 P( d4 I
" H# U- }3 m' ~# ?6 o  ask roads [ set pcolor white ]
3 e; W0 N+ y- \: O8 o+ R% s    setup-intersections
" s9 V! V, _: z$ ~; l" ]0 send
5 K; E+ y: f0 q$ I2 ^: S+ E& h其中定义道路的句子,如下所示,是什么意思啊?+ L! G0 E7 ?+ E' s* A* @
set roads patches with
% l" }2 ]! H7 Z/ \& _. l# ]    [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or. z6 ^6 Z$ H! B- q7 E6 @3 a
    (floor((pycor + max-pycor) mod grid-y-inc) = 0)]! v% [: g! q! f
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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