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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。5 C, t! r5 z/ C3 m
netlogo自带的social science--traffic grid这一例子当中,
& `+ E- I) x; `4 X9 |- sglobals# v! {. `* }0 q4 e, ?
[
: E \6 k6 p1 i' R! U grid-x-inc ;; the amount of patches in between two roads in the x direction) K! F+ r; C8 k+ G
grid-y-inc ;; the amount of patches in between two roads in the y direction
8 @6 K( L4 w' R acceleration ;; the constant that controls how much a car speeds up or slows down by if
' Z# p: Q0 e. w ;; it is to accelerate or decelerate A8 T% p' ]8 o. C# y
phase ;; keeps track of the phase
9 `- W* O$ G. N" E; E$ D" b3 b( ] num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
* w9 X3 m/ N* |6 r8 r1 S current-light ;; the currently selected light" p( Y+ B' z m* d" D& O% B4 Y
$ H. \0 `- N/ P5 F9 p ;; patch agentsets
' U) ]. K U6 A$ @) D' x* D$ Q: B intersections ;; agentset containing the patches that are intersections
% O7 E3 Y, [, o9 X4 Z% Y roads ;; agentset containing the patches that are roads# M! o {: Y8 L7 R
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turtles-own5 h0 Z; F7 d' J" w' |* D) Q) K, o
[
; t9 H# E1 s' r4 X4 L/ } speed ;; the speed of the turtle3 c9 b; A( t( H- O
up-car? ;; true if the turtle moves downwards and false if it moves to the right
* p4 L3 O5 l1 }0 }) F wait-time ;; the amount of time since the last time a turtle has moved9 G: f* C- A5 V1 m
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patches-own! j8 J/ u) N5 ?# E3 o' }
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intersection? ;; true if the patch is at the intersection of two roads
' G0 V6 T1 G2 y3 B% @$ r# g# b green-light-up? ;; true if the green light is above the intersection. otherwise, false.
, z7 y+ e, @+ u6 n ;; false for a non-intersection patches.
! w* Z T* k: B my-row ;; the row of the intersection counting from the upper left corner of the
. e9 ]( L7 K) ?% r! w ;; world. -1 for non-intersection patches.3 `$ {/ d) y- n) s+ C) F
my-column ;; the column of the intersection counting from the upper left corner of the
+ ?' I, d2 ?# k. _3 L ;; world. -1 for non-intersection patches.
1 n& r5 c* O7 a% d+ a; m4 A: k my-phase ;; the phase for the intersection. -1 for non-intersection patches.
; o9 V, ^7 M+ u. H/ f' ^: a auto? ;; whether or not this intersection will switch automatically.
& C" }' Z, Z+ c0 k$ f) a) ~" x ;; false for non-intersection patches.5 n' D4 b& V1 m6 m, `9 y
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;;;;;;;;;;;;;;;;;;;;;;
% C1 V+ V( E2 G" J. h- t;; Setup Procedures ;;6 q0 b! s- h# V7 `8 {5 o' ~+ x
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;; Initialize the display by giving the global and patch variables initial values.
+ u) u H7 i0 _% a0 }- ]' J7 ~9 q;; Create num-cars of turtles if there are enough road patches for one turtle to( t3 D) C8 P' p& Y$ `- V r
;; be created per road patch. Set up the plots.4 Q: S6 `( D4 `" s, [
to setup
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setup-globals
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' H: c* }, U, r- ` C ;; First we ask the patches to draw themselves and set up a few variables S3 X7 Y$ i% S4 P% R, v
setup-patches) {! j2 h# x2 q! |2 ?7 ^% G# o
make-current one-of intersections1 D# @% A2 \# \, _# z* Z
label-current
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- A' {; N8 Z2 Z5 ~ set-default-shape turtles "car"0 J% I7 d+ M" S
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if (num-cars > count roads) b4 ^0 Z- X1 I! ?
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9 \9 {9 i( v, c9 x user-message (word "There are too many cars for the amount of "+ k( M7 T& h; J% L7 @
"road. Either increase the amount of roads "
% j( T x' ?. L/ d2 d: L2 z "by increasing the GRID-SIZE-X or "; h3 _1 i. [6 d* K4 E3 e
"GRID-SIZE-Y sliders, or decrease the "2 c+ J$ k/ ?0 S" H! Z1 ]2 q
"number of cars by lowering the NUMBER slider.\n"
1 x" l5 p5 c& d+ s5 _1 G "The setup has stopped.")# L3 `0 p% i0 `1 ~
stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color0 c" I( K! b, e! p* C* ?4 N
crt num-cars
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2 R _: x0 `9 U+ ^, H. |- y setup-cars
8 Q+ T7 A! [! K8 x C* @% A2 _! i set-car-color4 h! D( O. f; C
record-data
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% w3 W5 D9 d+ I) H8 M+ Q: c ;; give the turtles an initial speed
. x" N, A7 k- c" h' Q ask turtles [ set-car-speed ]' {0 C/ y! \9 J
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reset-ticks
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' I% \) B, {. `4 r- m;; Initialize the global variables to appropriate values
) X' K3 A& Y% d' _7 Pto setup-globals
! c6 [. W; b5 A. \# o set current-light nobody ;; just for now, since there are no lights yet
' h( a1 d! D) A) q/ o# S set phase 0/ n! l6 C0 @! F# ^ Q/ f; i1 F$ S' n
set num-cars-stopped 0
- E4 k' H! G9 e) n3 q' @2 E1 ? set grid-x-inc world-width / grid-size-x* Y: L( n6 Q# f% E6 ?& k
set grid-y-inc world-height / grid-size-y
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5 R; ] D b3 H& ` ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
- t4 g+ U- ~: ~ set acceleration 0.099
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8 e" @6 A2 i5 o7 W( Q" b;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
/ _8 a6 {3 [0 g" f0 T* S% s" F;; and initialize the traffic lights to one setting0 X" G5 s" U; m" P' }' y+ W* l1 C2 E* V
to setup-patches. `' ?' B3 b/ D: O
;; initialize the patch-owned variables and color the patches to a base-color
! l1 }! u( b6 b0 { ask patches4 S, n7 x7 ^. ^2 r+ y. B. t, H$ {
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set intersection? false
! ]0 }" e1 g9 C6 V& ] N4 w set auto? false3 c( s% M; p) l3 l# r
set green-light-up? true8 F7 ]7 Y( f9 n9 s+ u& n* O0 y1 @
set my-row -1
0 _0 e! Q5 @5 y set my-column -1# J- z- n- t2 X8 t/ [9 Y
set my-phase -1
8 h7 g+ v/ f; E set pcolor brown + 3. ~& k* G& n, O, |
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6 _; }6 n' [6 F+ Y* A ;; initialize the global variables that hold patch agentsets9 d0 h3 R- a9 C0 R1 D1 h$ R
set roads patches with) a7 A0 f. n, a
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
/ }" F& L/ g- Q, C' ?6 g (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
/ X: v/ K0 t8 V" O, Y# U set intersections roads with
a& k+ {( S% [8 f. Q$ u( K [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
1 S' Z6 S/ T1 a$ ?% _" z (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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( K, x+ K7 d$ W! B3 o ask roads [ set pcolor white ]
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end: ?' m- p0 J: Q, Y: e0 t
其中定义道路的句子,如下所示,是什么意思啊?
$ [4 c2 \' ]! E! Y; k set roads patches with
. g; ?4 ~; r# c& @# \. u [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or7 B# c. O2 L% k: i2 M- c
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
5 M- l- L3 e: y: c1 r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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