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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。, }# c5 F) h+ ]' \8 C
netlogo自带的social science--traffic grid这一例子当中,
9 [7 t) G) e; Z4 _9 fglobals
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9 p; D" B0 J+ z grid-x-inc ;; the amount of patches in between two roads in the x direction
5 T0 f( @: F" _: m' B3 { grid-y-inc ;; the amount of patches in between two roads in the y direction5 a, |, w& \ j% r8 ?
acceleration ;; the constant that controls how much a car speeds up or slows down by if/ T; b' [, ^5 J
;; it is to accelerate or decelerate4 n/ X9 v% ?0 v- F) ]" A4 d: `6 K* r
phase ;; keeps track of the phase
1 g3 m: t3 c. W5 t9 X J num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure& V# m: O6 z6 J/ Q: d
current-light ;; the currently selected light
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;; patch agentsets- Y `7 u1 k& L; W! ^1 A
intersections ;; agentset containing the patches that are intersections4 `5 t2 {. _8 \" a
roads ;; agentset containing the patches that are roads
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: `/ W% U8 x2 B1 Yturtles-own, [; g$ h/ g+ e( S
[
5 l6 a: P" P& e3 w speed ;; the speed of the turtle2 b. T5 ^) ?7 T, T
up-car? ;; true if the turtle moves downwards and false if it moves to the right; B# {9 H1 n4 a$ x$ w5 e" }
wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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: I/ K: _# V+ U" w: P intersection? ;; true if the patch is at the intersection of two roads0 O5 o/ |' w( W9 h
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
l2 Y4 R, @/ ~. b; ~0 D! e ;; false for a non-intersection patches.
% ~1 @( e3 Z M my-row ;; the row of the intersection counting from the upper left corner of the
1 R; V, I+ K3 T2 c4 S \4 K: N ;; world. -1 for non-intersection patches.5 L% @( M( L: U3 \/ {
my-column ;; the column of the intersection counting from the upper left corner of the' F6 `6 y: w7 P) P( p% ~
;; world. -1 for non-intersection patches.$ U* Z* m B' D# ~" j8 z$ K
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
$ ^* l7 x9 j! W2 i/ c. U. P" R) d3 d auto? ;; whether or not this intersection will switch automatically.2 K0 z- H( T5 O0 k! w) q0 x: W
;; false for non-intersection patches.' P }8 r7 ?/ u. F0 j7 {
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c, ], j( h" ^: [' t( a;;;;;;;;;;;;;;;;;;;;;;
6 M$ l9 X* S$ d$ c;; Setup Procedures ;;' ^1 G2 W: G! R" h2 p8 D$ j! c" M
;;;;;;;;;;;;;;;;;;;;;;4 l2 N. g+ o/ p2 j2 X- [
9 W6 E8 D- ]* ?7 \, y' g3 |# N+ ^;; Initialize the display by giving the global and patch variables initial values.
* q& z* m5 C! t- y3 ~;; Create num-cars of turtles if there are enough road patches for one turtle to0 Y8 ]! R8 ~$ ]4 y
;; be created per road patch. Set up the plots.. k/ ^2 A. z/ Z. x2 B# l- ?
to setup
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1 N$ Q/ L3 k7 v, d8 C" k setup-globals7 W% U w" N( X. E/ w
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;; First we ask the patches to draw themselves and set up a few variables
. Z6 d5 P. i5 e( M C- S setup-patches
$ u$ g& q* ^8 O) T+ T make-current one-of intersections
4 A% @ M$ e+ r8 d0 R: a7 ] label-current5 r: F% y# g6 X& {) k
* c; V/ ^0 d) @2 v8 P set-default-shape turtles "car"( E# t2 h- \! \7 m% L7 C
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if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "
& L) H) o+ @2 D1 f "road. Either increase the amount of roads "
+ m" K/ E. e0 o, e. d. d "by increasing the GRID-SIZE-X or "! n, g9 p! w: u$ H
"GRID-SIZE-Y sliders, or decrease the "
5 w. W" c1 D* t "number of cars by lowering the NUMBER slider.\n"
( o* n! z1 b6 ~* | "The setup has stopped.")
9 j6 ~$ U& D2 S1 Z stop4 k, i! e3 v5 f! V! y& J7 R) p
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color: O' U) Y! T- a# `, l9 t: N
crt num-cars
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setup-cars' ]/ G7 x% {5 |
set-car-color' v4 f( q2 i, K! l5 y6 e
record-data. Q' m, X( i C7 t/ G
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: j& A7 G7 z( Y$ W: C5 J6 Q2 W" q. ] ;; give the turtles an initial speed
: m( n. s% _" K' K) M ask turtles [ set-car-speed ]
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. u: n y) h- ^0 Y. Q& ` reset-ticks
2 V9 Y1 ]$ C2 @$ `end
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;; Initialize the global variables to appropriate values
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set current-light nobody ;; just for now, since there are no lights yet3 e6 r$ U- R6 z; m
set phase 0
7 j3 H& x" h) }& c- A9 | set num-cars-stopped 0
3 M3 k9 v, I( p9 O set grid-x-inc world-width / grid-size-x* `) B9 D4 q# \3 a! [3 X6 ~
set grid-y-inc world-height / grid-size-y
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary9 x4 u* C7 I- e0 `8 O2 ~) d% [
set acceleration 0.099' R$ \) x( r4 t* w/ x
end
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8 R! D1 d3 Z; r# _ ];; Make the patches have appropriate colors, set up the roads and intersections agentsets,
5 h, q: s3 n2 b+ I;; and initialize the traffic lights to one setting
' Q8 p3 W6 {2 t" Bto setup-patches1 j" W5 Q( o- h3 s% p" p
;; initialize the patch-owned variables and color the patches to a base-color
/ U+ Z% D2 _1 q+ A) X4 B. \* ~ ask patches) W7 a1 z$ N9 K9 ^
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2 S0 G! G8 y) {4 }3 N set intersection? false
( I" Z$ X6 w, F+ L set auto? false, r, J: ~, P- n- T$ F: w7 M
set green-light-up? true H4 r1 v; s( S2 `9 R6 m8 r. i
set my-row -19 D( c$ h) ^, |
set my-column -1# C' y: N: p# @
set my-phase -1: I8 S& ?+ c1 U$ ^2 T: T
set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets
7 s6 E' ~* n+ m/ n+ u3 t% M set roads patches with
* w. v! p7 Q0 u: e5 C [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or. a' N5 `" E. q6 T/ [
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
* A: J1 z) H+ I, Y# T set intersections roads with$ S( c9 E- W0 E& r* W1 Z) e
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
9 b8 K S7 r- L4 W2 Q$ o- ] (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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' C& I0 I+ [% {) _4 I( J ask roads [ set pcolor white ]
' O) V- C+ a: V- d6 H, N4 h% t6 b 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?
! U& t* w: ~+ P( d: x/ M- K$ ^: r' G set roads patches with5 f3 q2 N2 M4 A: E! z* n9 e; t$ S
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or1 C1 B1 p; D: S. Q" t; l
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
5 T: T k( e: f. l4 u8 y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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