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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。) [& M- K) _4 Q6 {4 }6 {: A0 ^2 V
netlogo自带的social science--traffic grid这一例子当中,
! z) K7 y: R" }7 n, gglobals* u) z" Y X3 P9 i# E! x- T
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$ _4 M+ ~" L% f& J$ ?3 I$ } grid-x-inc ;; the amount of patches in between two roads in the x direction' h, o% ]: m) l8 j
grid-y-inc ;; the amount of patches in between two roads in the y direction. Q1 }# N* E" I2 k. \' x. U0 d
acceleration ;; the constant that controls how much a car speeds up or slows down by if
4 {$ F8 s# w' {& x- ~0 d ;; it is to accelerate or decelerate
# z2 _5 Q+ {# d1 x phase ;; keeps track of the phase, o, u4 ^ k+ r# _$ D5 z
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure: ~! {- Q) O$ ]/ U+ i. I
current-light ;; the currently selected light
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;; patch agentsets, B. V9 U$ J; P0 k' y* t3 {& ^$ l
intersections ;; agentset containing the patches that are intersections. L# ^, t# c5 v5 U p9 Z
roads ;; agentset containing the patches that are roads
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) g; u' c' z: I% y2 R6 c. ?turtles-own# B- V6 y1 T! ^( \
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speed ;; the speed of the turtle1 B8 M# |! [, f: S8 D% g- F+ U
up-car? ;; true if the turtle moves downwards and false if it moves to the right
+ U1 W+ u4 \. b* Q wait-time ;; the amount of time since the last time a turtle has moved+ L# S4 L8 l. t) H% V: q
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patches-own: Y" `2 w4 T& d) ~! R C" O
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% }; x" {- S+ j9 C) P- |* e intersection? ;; true if the patch is at the intersection of two roads6 t/ x$ _3 {# T- y5 ?5 [; m0 v" O
green-light-up? ;; true if the green light is above the intersection. otherwise, false.: I# U1 ^1 q2 y
;; false for a non-intersection patches.
' b$ l( |9 Z! l; j' K0 E9 H' Y my-row ;; the row of the intersection counting from the upper left corner of the5 J1 k/ x! H* t$ b* C2 N
;; world. -1 for non-intersection patches.; F; K& x3 y- @7 @1 O5 D# \9 `
my-column ;; the column of the intersection counting from the upper left corner of the$ G) J( h; |& a* }9 L
;; world. -1 for non-intersection patches.0 `% O6 f: _/ ]& M
my-phase ;; the phase for the intersection. -1 for non-intersection patches.! N0 R$ o: q' f! w
auto? ;; whether or not this intersection will switch automatically.
* b9 |+ \' @9 a0 U* w ;; false for non-intersection patches.# O& m$ F- O- V( i( h( Z9 y
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. z" G' k9 ]* r$ C2 o1 Z;;;;;;;;;;;;;;;;;;;;;;2 m9 s! U! a) E) }( f! a8 M
;; Setup Procedures ;;
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+ v( S# o4 V& I8 a4 @0 s4 O;; Initialize the display by giving the global and patch variables initial values.
3 q1 g2 y. C' r" d, c0 d;; Create num-cars of turtles if there are enough road patches for one turtle to* J6 r1 T4 Z% v ?# s
;; be created per road patch. Set up the plots.0 r# I+ z2 I4 E/ H8 W
to setup: o. T: o2 H0 T! K0 y
ca
* x. Q4 ^) R1 y% Q" J5 K setup-globals
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& q& Y# E( f u! c4 {/ N ;; First we ask the patches to draw themselves and set up a few variables5 Z" ~4 `6 {4 L" v
setup-patches
8 E8 e% R2 P8 i) |9 t* w: o make-current one-of intersections- q( R% \* F- Y- G# n
label-current
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set-default-shape turtles "car"
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; ]4 F3 q0 T# h7 [6 G2 x/ y if (num-cars > count roads)
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: V. E: U$ g7 D6 M, a user-message (word "There are too many cars for the amount of "
1 J" a3 Y* k. j "road. Either increase the amount of roads "- W) m) p- L" O: i x- x
"by increasing the GRID-SIZE-X or "
, [# r- G; K1 G0 v+ X' J "GRID-SIZE-Y sliders, or decrease the "- |6 w3 F! n1 b% k" b" O
"number of cars by lowering the NUMBER slider.\n"
# H4 ]/ A2 z2 r; B' B "The setup has stopped.")& w, X4 g( n) S! C
stop
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8 D# w i1 n+ |2 ~6 w+ K ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color3 o; b, e3 i4 T: M8 K9 {6 u
crt num-cars
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setup-cars8 y( t/ \% u% U# O; {
set-car-color
' v# N* Z3 u% E* v; q record-data$ @% T: p$ c2 I% f
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;; give the turtles an initial speed
5 e) s+ s0 x; Z' g2 E* s ask turtles [ set-car-speed ]/ p( I+ M, V6 g! Q0 z
7 f+ L( J6 K, y, V1 M reset-ticks
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' R6 ?* v* \1 N3 e3 i;; Initialize the global variables to appropriate values; n% U! }" w# ^) H
to setup-globals: u0 B- u) D" k; S( P& r
set current-light nobody ;; just for now, since there are no lights yet1 U& m: |, z" y- h6 B& ~
set phase 03 g6 I& A1 {8 _7 C; W$ b
set num-cars-stopped 02 e+ O, |: T }4 P/ S
set grid-x-inc world-width / grid-size-x! ]# G. B1 j: v# p9 ?: q7 ]/ g
set grid-y-inc world-height / grid-size-y9 Y# H" Z( {0 \5 R0 G
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
5 H4 C0 H. {/ W set acceleration 0.099
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. [" S4 l7 v7 s: Z;; Make the patches have appropriate colors, set up the roads and intersections agentsets,0 F. y5 W L6 D1 D& q
;; and initialize the traffic lights to one setting! k: r2 n, R8 l! s1 l) |
to setup-patches
" h$ d: P; F! x' u. F8 R2 K! d- _, z2 [ ;; initialize the patch-owned variables and color the patches to a base-color
: e7 [8 p( A- V5 M2 n ask patches7 R$ b+ Q2 S, {2 O6 `% t
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set intersection? false
4 v2 z% i y) V1 K4 \. X: X set auto? false# }* t$ t+ q: h+ T
set green-light-up? true) q, i; l3 ]. ]+ D4 S; M
set my-row -19 F# Z8 o9 o, Z: O2 b3 p! C
set my-column -1
+ v. U4 Z7 y" ?/ j: f2 Y set my-phase -16 x1 y# H6 c2 A6 @" H0 Z( o5 X1 s$ Q
set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets
+ G: c' J$ {. R; Y set roads patches with/ k& x$ L. l3 g/ T
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or" V, a# _$ p5 a7 b6 g0 M
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]' v5 L/ Y M/ u0 e- l& B
set intersections roads with
# @5 {$ F, _4 S" C0 f [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
& j, ]' w5 `5 c (floor((pycor + max-pycor) mod grid-y-inc) = 0)]" L) i2 |* [/ |% }1 S% X% Y
5 I5 q! L0 B/ U) \ z% w: h3 s ask roads [ set pcolor white ], T2 [3 a2 e! S4 Z- G, H o- @
setup-intersections
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其中定义道路的句子,如下所示,是什么意思啊?$ ?4 O) [# T ~9 J; p( @
set roads patches with
4 o7 M. V/ {( ^3 U, k/ v' R [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or% q# H8 u! |. a. \% o |
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 D2 }6 F L5 T m: B$ P7 |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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