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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。
4 u. b9 B& }$ Q1 @ A' y: Bnetlogo自带的social science--traffic grid这一例子当中,1 l5 y! u! n0 D B3 q R
globals
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grid-x-inc ;; the amount of patches in between two roads in the x direction6 _- x! O8 R* K; M [$ M3 z
grid-y-inc ;; the amount of patches in between two roads in the y direction
* H3 L- c' L& h$ f acceleration ;; the constant that controls how much a car speeds up or slows down by if
' ?" o2 @8 U7 {# ~ ;; it is to accelerate or decelerate2 L5 i& H% Y5 s/ H
phase ;; keeps track of the phase
& K3 n9 q, c" I0 e8 [ num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure" @7 E4 p" i. |6 r
current-light ;; the currently selected light/ z2 `9 u" X& e5 _# \
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;; patch agentsets
/ t/ Z$ h# j. z0 C. L5 R; j intersections ;; agentset containing the patches that are intersections
. N- {; _5 r- s4 U" I9 z; Y( k roads ;; agentset containing the patches that are roads
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turtles-own+ Q6 I9 q8 M$ [; t
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speed ;; the speed of the turtle+ b$ @" d I3 N! r$ A8 \: e3 |
up-car? ;; true if the turtle moves downwards and false if it moves to the right$ \( [& w; B z" `" O
wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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6 B- E0 n, r1 Y8 ?4 N' l+ r$ j/ y intersection? ;; true if the patch is at the intersection of two roads
, d! H5 W6 r. m# s. ^ green-light-up? ;; true if the green light is above the intersection. otherwise, false.
+ U* M* o! |- S3 V& G ;; false for a non-intersection patches.8 ^7 t8 l& L; X, g1 O% j$ T% f, @
my-row ;; the row of the intersection counting from the upper left corner of the
- J9 U+ u% p* p ;; world. -1 for non-intersection patches.
" T/ a G) w2 s1 @. A: d, Q my-column ;; the column of the intersection counting from the upper left corner of the% [9 J+ L: X; _# X' D7 E
;; world. -1 for non-intersection patches.3 m8 ]7 S6 x) Y
my-phase ;; the phase for the intersection. -1 for non-intersection patches.2 W2 g, h6 H/ m' ^; N
auto? ;; whether or not this intersection will switch automatically.
5 f' \, G) P+ W% S6 A8 j ;; false for non-intersection patches.: M0 a$ U, `0 d' |- t) ?7 \
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5 K$ K+ `/ Y+ z- e& n;;;;;;;;;;;;;;;;;;;;;;+ P. z6 }/ @0 q
;; Setup Procedures ;;
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;; Initialize the display by giving the global and patch variables initial values.
6 _" j, b; x6 P; b;; Create num-cars of turtles if there are enough road patches for one turtle to
0 p& X) G& Y1 s X; o;; be created per road patch. Set up the plots." u: G2 u' W7 f) A/ J
to setup& k4 H$ e! F# R
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setup-globals
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# |) k! x7 C8 p" T9 q; v ;; First we ask the patches to draw themselves and set up a few variables
+ S: o' M& z6 { G* M setup-patches
9 G; j' j3 t5 l make-current one-of intersections
: P3 T8 i2 g) H& ] ^ label-current# {5 p0 t# E) ?
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set-default-shape turtles "car"& W- u, \5 v; w9 s* Z$ a: z0 E
; n- j+ n7 Y6 @; L0 Z' W if (num-cars > count roads)$ W) K+ k. O* F8 d, P5 n- m' ?
[
( S7 q) t' A& V% z: ?6 t user-message (word "There are too many cars for the amount of ": c0 E$ Q9 l0 ]' n. z, k
"road. Either increase the amount of roads "+ O# \; ], L* _% `2 \
"by increasing the GRID-SIZE-X or ", m+ y, n7 j; \+ N- h
"GRID-SIZE-Y sliders, or decrease the "
6 ~, C4 U" S/ i2 v6 ^ "number of cars by lowering the NUMBER slider.\n"
Z7 A$ X2 s$ l/ T: y "The setup has stopped.")/ y6 ~4 T/ B( \- l% y3 k; ~4 f
stop
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3 i' _# g: B& L, Y( a. g. m# k+ A ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
, J) s. L- V+ e) w crt num-cars- n& p# _ P. z t* l d% p0 Y
[
' T4 N- e7 q: W setup-cars
& e5 Y: H6 \! G: i( e+ X. L: V set-car-color
; c5 K8 p5 J2 P/ _+ Q record-data6 U5 o ^1 E( @% X7 q5 Y v
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;; give the turtles an initial speed
& J5 f& x8 h$ |+ H% \ ask turtles [ set-car-speed ]
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8 o B% `0 v4 V5 G/ ^ reset-ticks
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2 M- }. X1 O# T1 }4 Z;; Initialize the global variables to appropriate values0 G0 Q4 G" y, b4 q0 ]9 A5 q
to setup-globals: \* f, _; `( a8 ^' D# f- `4 u+ x
set current-light nobody ;; just for now, since there are no lights yet
* Y" [! L* y2 `1 S set phase 0
|: Z' Q7 i* j2 G; Q5 r. ?1 S set num-cars-stopped 00 @ I( E1 O. E/ r+ h
set grid-x-inc world-width / grid-size-x
8 j6 K5 _3 a# J' L ~ set grid-y-inc world-height / grid-size-y( g" z- d$ q! F7 G4 |0 R- 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. W$ G- x1 ^5 z9 P- M* T
set acceleration 0.099. E8 k: P' M7 C$ e2 W- t, _0 }. d
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
$ d. ]% E' K7 z/ f3 v;; and initialize the traffic lights to one setting$ x. B0 Z2 _: i2 |
to setup-patches/ _- W2 i# q& v; a
;; initialize the patch-owned variables and color the patches to a base-color9 E6 h7 q+ Z6 M& U [
ask patches
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set intersection? false4 R6 f) r% x9 k$ g2 H; ]
set auto? false' a+ f7 Q7 G2 c7 p
set green-light-up? true
6 ^& M. }, {& ]4 C set my-row -18 e& I/ N# I' y" \4 A# K7 O
set my-column -1" T' {6 t. m7 Z) b6 ?0 c: ^
set my-phase -1# s) q- ?/ J% h# T: ]8 l! N
set pcolor brown + 32 r! z! z, @' A1 M! k* Y5 b7 i
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;; initialize the global variables that hold patch agentsets9 P2 w; w v: e/ q. o
set roads patches with
$ i1 f! M% }4 ~3 A9 i4 r/ _ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
8 ?: B0 I$ ]6 d( Y) X (floor((pycor + max-pycor) mod grid-y-inc) = 0)]$ g$ R9 n1 U. q9 \
set intersections roads with& o9 l# H R. ~- i
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
8 I* W7 a' t, S2 j9 c (floor((pycor + max-pycor) mod grid-y-inc) = 0)]+ E, q& T% s: C) i: R+ x, o
+ p4 p0 l* @( l" {' T. c ask roads [ set pcolor white ]: h; Z% Q% ^9 V4 K- g! \
setup-intersections
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( \- l6 j' Y7 f9 j L其中定义道路的句子,如下所示,是什么意思啊?6 Z0 {7 t- S1 J; P; K, B
set roads patches with
0 n0 x6 g4 @2 ^ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or- p( `% F' N* T6 o0 X
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]& V1 M$ W# K: q0 E4 ~
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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