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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。
% J. M" y8 I3 E: o' U3 Qnetlogo自带的social science--traffic grid这一例子当中,2 M2 O8 Y. h! Y! b" o3 a' S
globals
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# M* d: ?- i! o( X( { grid-x-inc ;; the amount of patches in between two roads in the x direction
8 E' E# v! d0 `5 Y- i grid-y-inc ;; the amount of patches in between two roads in the y direction1 E0 ^+ m& F8 w% D
acceleration ;; the constant that controls how much a car speeds up or slows down by if" |+ D. K% R4 k& | k+ `. Z8 t! Y
;; it is to accelerate or decelerate
; @' J4 q7 b% F9 U, ?7 Y phase ;; keeps track of the phase p" K* p" q/ }/ Z& l
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure" |4 r4 v1 x" S, ~# P
current-light ;; the currently selected light+ K/ s' f: @7 K
3 S, P7 a2 \$ p" K6 w ;; patch agentsets
, _* o, y% g3 U A- {: l4 j% v intersections ;; agentset containing the patches that are intersections
+ t& I, T$ v0 | roads ;; agentset containing the patches that are roads
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/ _, Q6 i7 I3 J3 ^turtles-own
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/ m5 ]( ?0 d6 M; h, m, j speed ;; the speed of the turtle; s* v3 q. Q6 E( f* d( O. A: C
up-car? ;; true if the turtle moves downwards and false if it moves to the right3 ]2 U5 B8 N9 O, O: v- ^; i* k" ~
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
5 W9 ~4 W& E6 E+ @ green-light-up? ;; true if the green light is above the intersection. otherwise, false.
" }9 `3 s: P0 \- T# i* i- h ;; false for a non-intersection patches. u# t1 N p$ R$ z1 c
my-row ;; the row of the intersection counting from the upper left corner of the: j+ b' R5 p- I* g/ g4 ^
;; world. -1 for non-intersection patches.
6 {( |$ p2 B/ _% l5 f9 M my-column ;; the column of the intersection counting from the upper left corner of the
5 l% k1 ?- G) B' s. o2 R/ | ;; world. -1 for non-intersection patches.
( v- g% E3 |8 r my-phase ;; the phase for the intersection. -1 for non-intersection patches.
8 ]: [3 Q: {2 ]8 h& K6 Y: t auto? ;; whether or not this intersection will switch automatically.) B# O3 `4 v& D" r. f+ |+ P& `* @
;; false for non-intersection patches.8 S! |" o0 ~/ c f* r+ P
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3 n* |( b3 c0 h5 K& I/ U;;;;;;;;;;;;;;;;;;;;;;$ T6 Z# A' G; Y, U2 c
;; Setup Procedures ;;
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( b' U) l! v n0 H9 o$ ^;; Initialize the display by giving the global and patch variables initial values., i% Y: L$ a& |
;; Create num-cars of turtles if there are enough road patches for one turtle to+ s0 u I) }3 d+ s/ W
;; be created per road patch. Set up the plots.& F; \. D9 Q5 ]) ?
to setup
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setup-globals" h& `1 M6 T; l [8 m4 J& X+ Y
- e$ d: w/ D; j- o1 D ;; First we ask the patches to draw themselves and set up a few variables
0 n3 _4 }# q: s( T4 A/ z& k3 ^ setup-patches) A% p8 H( H! _; w" ~; S* x x
make-current one-of intersections
' R( q+ k- F4 x label-current
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1 A8 Y; F0 I/ o set-default-shape turtles "car"
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if (num-cars > count roads)
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/ {* |1 g: M+ @% h- a user-message (word "There are too many cars for the amount of "& ?" i4 o7 Y1 g j+ V, n9 I
"road. Either increase the amount of roads "
, H% c9 D0 f9 ]2 K& O' b+ H1 k) Y "by increasing the GRID-SIZE-X or "
; d8 Q* l$ Q' m "GRID-SIZE-Y sliders, or decrease the ". E! o a& G: K
"number of cars by lowering the NUMBER slider.\n"
; o9 `8 T! `3 k "The setup has stopped.")
: p' v6 k! t' q stop: i2 G3 L3 [" ?$ q2 V1 T
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# z/ D2 g7 A0 ~1 E9 Y ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color: c* \0 N, k; l, v) w0 V8 T# k
crt num-cars5 l3 l/ T' E& U* b
[
1 ~2 i; \% A7 ? setup-cars
' @: K9 m' Y6 O( ?) f. B( ` set-car-color
5 T2 L) D$ S) ~% K/ j8 }, y record-data
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2 E1 d# Z; l1 p2 I ;; give the turtles an initial speed
( O9 F+ J9 z+ f- O5 a ask turtles [ set-car-speed ]
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reset-ticks
3 @1 q+ D& G% E* V# u" i+ D7 eend
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' C* F% L6 c# F;; Initialize the global variables to appropriate values
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% M4 U& r& e+ X5 I" t set current-light nobody ;; just for now, since there are no lights yet. p* @ }+ q5 x4 J1 Y
set phase 0+ h% z2 Q+ o% q- L! e+ Y- f" T
set num-cars-stopped 0
0 T5 V" A% p. c8 H set grid-x-inc world-width / grid-size-x' Z" O* Q/ g. n0 |( z3 w0 }+ { f, p
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 boundary
9 u7 B8 A2 Y. |0 B2 j. |% J set acceleration 0.0995 X: x9 t0 H: ?
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,* v6 S1 k, Q- a+ `( |! t
;; and initialize the traffic lights to one setting5 X5 a3 [2 l# \& r1 x7 D
to setup-patches6 J% e; W0 K2 G7 R: |
;; initialize the patch-owned variables and color the patches to a base-color
/ K( g8 `& O' A/ G& h, U ask patches; \$ A; U( y3 V1 p, L& ?, d
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set intersection? false4 S" ^: P' R `# H5 h3 m
set auto? false2 k4 ^/ _0 _& V8 `6 k
set green-light-up? true `. M. r2 P% k; W7 a: W
set my-row -1
5 _% A$ m' Y4 e" E set my-column -1: F ]6 Z8 w5 w- Q( W8 t$ {4 f
set my-phase -1 ~1 T/ ^2 Q, k/ C P
set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets
; G- d' c8 _- U( Y. b set roads patches with
( e+ [- Q* x' B9 B4 Z$ c [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or/ S/ n% f. \1 z0 k8 u4 E
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]. p* s7 u. Z3 ~$ ?
set intersections roads with0 i% [& s+ Q9 t! `+ J! s5 J
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and4 \9 B7 x y& I* k$ O6 Q0 d
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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5 C, O" f7 G, B/ C2 A! _# w4 s ask roads [ set pcolor white ]8 B8 v0 @: s6 ^0 P- h; t
setup-intersections
( _, ~* ]1 D3 j( W& } m }end
$ l5 M# I8 h0 P9 T其中定义道路的句子,如下所示,是什么意思啊?1 x7 c( e# \( F6 K) z4 W
set roads patches with
8 ~# K. \- r$ y5 k1 \+ ~, w% x, d [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or- l2 n! ~! b- G& h9 \" ^
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
" Y" X5 l& T+ Y/ L s! `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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