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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。
E* e) E. A* V0 g5 Y0 y" Tnetlogo自带的social science--traffic grid这一例子当中, v9 m. r U$ W
globals
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8 ]8 N; ^9 l" B grid-x-inc ;; the amount of patches in between two roads in the x direction
4 |( v, }. i/ p* D! z( u grid-y-inc ;; the amount of patches in between two roads in the y direction
: C- C8 S) @ e! p& t1 c z7 v, z' W acceleration ;; the constant that controls how much a car speeds up or slows down by if
+ c0 \ {9 B" } ;; it is to accelerate or decelerate
& J! e* ^; u% K' c. f phase ;; keeps track of the phase, e8 w& p' ]) O$ a
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure3 i+ ^3 O+ c( [% q
current-light ;; the currently selected light
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;; patch agentsets) y- z, ^8 {9 N( N1 y
intersections ;; agentset containing the patches that are intersections
, O3 Z. D; D" {, ^' m" s0 X: K5 l7 n roads ;; agentset containing the patches that are roads
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6 B/ j/ O* ]9 }) Rturtles-own5 T. T* E" [( a* H
[
7 e, E3 N5 ]4 }1 h& j+ y( U speed ;; the speed of the turtle# e+ _1 ]& C0 B! T4 r5 l8 K9 ]
up-car? ;; true if the turtle moves downwards and false if it moves to the right
+ Z! h `; j: ?. C' E9 a4 Q1 S wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads
. J: N! c3 P7 W green-light-up? ;; true if the green light is above the intersection. otherwise, false.1 x4 G: c, {* q* \ `% T+ Z6 g
;; false for a non-intersection patches.
* i" z+ F) I% I/ ]& T- H1 ? my-row ;; the row of the intersection counting from the upper left corner of the
4 Y, ^5 T# \! |( { ;; world. -1 for non-intersection patches.* f+ v$ I! F6 k$ l
my-column ;; the column of the intersection counting from the upper left corner of the
+ u5 d1 o/ d% c: M ;; world. -1 for non-intersection patches.
! W- Y5 H' X# W/ o4 x6 M# T my-phase ;; the phase for the intersection. -1 for non-intersection patches.
% [' U" c, y2 a# _( A auto? ;; whether or not this intersection will switch automatically./ r. j) c- J6 u0 h
;; false for non-intersection patches.% S' I3 z4 A. X
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;;;;;;;;;;;;;;;;;;;;;;2 s1 o$ Z$ }1 L/ |, A2 W
;; Setup Procedures ;;" v( s+ `& u8 l `2 O* j3 ?( b
;;;;;;;;;;;;;;;;;;;;;;
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! Z1 ?, R/ `) d$ M1 |% O;; Initialize the display by giving the global and patch variables initial values.
5 }# L6 Z) t% K5 i' a3 b. s. m;; Create num-cars of turtles if there are enough road patches for one turtle to
; A5 y+ i, }/ I1 L: c;; be created per road patch. Set up the plots.
( W$ A- |# b+ x# W5 w) Q* A! kto setup
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setup-globals
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/ w9 z( {& X8 d* Y ;; First we ask the patches to draw themselves and set up a few variables- b; g5 A$ N0 @- L" V: l
setup-patches! w1 R$ u6 \- u/ y
make-current one-of intersections
/ H5 B$ U1 G2 D) v label-current) \' {" a( F& H
( y0 n e+ k! A+ Q4 w$ o) T' W1 Q" ` set-default-shape turtles "car"# c2 k- o: Y) n0 E- Y4 H
9 K* e: P9 @+ \0 U if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "
& o+ U1 F# L4 B7 b4 m; j Q+ ? "road. Either increase the amount of roads "3 L+ J) _+ q& i- V- p! B
"by increasing the GRID-SIZE-X or "
9 a- [+ r" H5 |/ c0 \: k "GRID-SIZE-Y sliders, or decrease the "
4 v r! \4 }8 z! | "number of cars by lowering the NUMBER slider.\n"; d! |0 ^2 p2 o; Q$ f
"The setup has stopped.")
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4 H3 r% ^3 T5 q ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color* R3 T' G1 Y3 k$ Y# ]9 t
crt num-cars- W8 B3 T8 l+ z# ~* t
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8 |" w4 B" A! C! o( J- Q$ h setup-cars
: ]% g, S! A% L set-car-color( r' `, `% }! L' G$ A5 V
record-data+ E$ E' L# ]: n
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2 U3 {! X4 I9 h/ R* p ;; give the turtles an initial speed
( [. l5 w3 ^0 H7 `% E3 A ask turtles [ set-car-speed ]
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1 B6 U% {# c$ n& l2 M6 P reset-ticks/ A5 [. V4 W/ X
end6 Z* H% Z4 l, }
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;; Initialize the global variables to appropriate values* c' O6 I1 `9 t4 O8 M& u
to setup-globals
8 S+ A8 V- K$ O- q% W P# a1 V set current-light nobody ;; just for now, since there are no lights yet
, }- B1 f$ J! o$ A d$ ] set phase 0' N |, g1 ~: ?4 f5 {+ Q' e/ g# I% i
set num-cars-stopped 0
[- h2 w7 O) N9 I5 T set grid-x-inc world-width / grid-size-x9 ^- K, J- S4 j( k7 @, u# c
set grid-y-inc world-height / grid-size-y9 j+ V7 Q" B3 V4 X
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary. P4 W7 u9 ]7 k J3 {
set acceleration 0.099
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,9 g4 Y& H8 m8 F: J1 @" V; ?
;; and initialize the traffic lights to one setting% c5 E8 n: F' K+ c9 p1 ]3 T; O+ L
to setup-patches
# M7 O) c/ n' X ;; initialize the patch-owned variables and color the patches to a base-color4 M( o, z1 \6 n% t2 c
ask patches" E1 k) ~$ z# _% r
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3 i5 L+ l6 L4 ? set intersection? false+ a7 Z/ q L) z
set auto? false9 k5 l2 J+ G& O) N+ Q
set green-light-up? true
, A$ a2 E8 {2 q& P* O! I set my-row -1& p E* |5 k- b% x0 b! I
set my-column -1
8 X# g+ l: d2 @ set my-phase -1
]) ?: Q. t5 N set pcolor brown + 3, }' n C3 M( G7 W2 F) G
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$ ?+ @6 t- ~( |+ |! P ;; initialize the global variables that hold patch agentsets
' l: k& }) o% H+ ] set roads patches with t, j% @* I9 t' a8 c" y2 x- @
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or. f. u* @6 l' M6 u
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
, }# N* Q! W: C+ w9 T/ ? set intersections roads with
) u D2 |$ C7 O2 S% x [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
0 t; d$ b3 S5 _) M: d& j( P7 m! p (floor((pycor + max-pycor) mod grid-y-inc) = 0)]- K2 ~, Y# W% s+ `
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ask roads [ set pcolor white ]( i1 T, C7 ~7 z/ u; ^9 F1 F" w
setup-intersections0 T' o3 Z# F0 N8 m
end
8 x; T0 p/ [ |) [* n其中定义道路的句子,如下所示,是什么意思啊?% F% z$ k Q) s
set roads patches with
n+ ^( b) q/ V' S+ f [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or X$ ]8 O7 e9 S( ?8 L, B9 ~
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
" p( x" ?3 D" _: `/ 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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