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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。& R2 X* V7 [4 G
netlogo自带的social science--traffic grid这一例子当中,' A, t. s C. }* b
globals
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6 I9 z8 S( K6 I2 H grid-x-inc ;; the amount of patches in between two roads in the x direction
3 U B4 y& j# C7 f5 O& ] grid-y-inc ;; the amount of patches in between two roads in the y direction; V, ]8 e1 Q5 a
acceleration ;; the constant that controls how much a car speeds up or slows down by if9 o4 k/ p9 f `. l9 v+ @+ P6 C( [
;; it is to accelerate or decelerate
' \/ K3 Z4 w7 a/ t/ q# z9 Z5 f phase ;; keeps track of the phase
0 I' N: Y' v' [+ v# M num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure5 {* m# A# ^: e+ [' g; X7 ?9 b
current-light ;; the currently selected light/ [5 R, o& ?+ L
) J; D5 v* E& m- z) m. x5 y ;; patch agentsets
" ]& `: U A0 }# r1 R intersections ;; agentset containing the patches that are intersections
8 p/ ]0 G9 l& ^/ L roads ;; agentset containing the patches that are roads
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4 i) Z- Y' f4 d7 q% qturtles-own6 q' h1 q# W2 H
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$ r( u0 `& S% w; v5 N k speed ;; the speed of the turtle
6 F7 l* h+ U7 c6 o3 X7 } up-car? ;; true if the turtle moves downwards and false if it moves to the right
: L: u' @! }7 b4 V wait-time ;; the amount of time since the last time a turtle has moved
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" \. r+ y7 _$ [( C3 ^% V0 E- S- v$ |patches-own6 Q0 z, n8 Y) ^2 T! }8 [" h
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intersection? ;; true if the patch is at the intersection of two roads
( x' O6 c/ X: x9 R. I green-light-up? ;; true if the green light is above the intersection. otherwise, false.
* y0 |8 }. _! ^3 R: R. a ;; false for a non-intersection patches.
: e. U6 X( w C/ F/ L my-row ;; the row of the intersection counting from the upper left corner of the! K) ~' s- i: l5 U4 C
;; world. -1 for non-intersection patches.
. @: I$ a/ `# ~. y; u my-column ;; the column of the intersection counting from the upper left corner of the# s+ k% ?" }$ }8 Q9 P7 p8 d
;; world. -1 for non-intersection patches.0 j$ N; }1 R9 |9 Y( o0 `" G
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
3 R* W, C* g/ H& R- w auto? ;; whether or not this intersection will switch automatically.# c5 D0 A/ F/ c- K U$ ~
;; false for non-intersection patches.
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" l' {5 E9 O- B0 p, X& W7 e3 N;;;;;;;;;;;;;;;;;;;;;;
, L0 G& p) J, ?7 T! R1 E;; Setup Procedures ;;
) L& f# |+ e, l" R;;;;;;;;;;;;;;;;;;;;;;
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- S6 X" r$ Z+ [;; Initialize the display by giving the global and patch variables initial values.! t) F7 F& V+ [
;; Create num-cars of turtles if there are enough road patches for one turtle to
) x4 ^7 E" v, O q3 O8 q;; be created per road patch. Set up the plots.* A6 S5 ]# N5 c
to setup4 g7 s" I* o: e. _4 V' ^, J
ca
$ ?' C, J. {7 k- b! Q" s8 p setup-globals6 z9 z* ]* w/ y0 S0 M4 d2 w
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;; First we ask the patches to draw themselves and set up a few variables
( S E3 f0 R' K% k, W2 A- T setup-patches ?) c a& Q, d. @8 ]
make-current one-of intersections
6 W6 g7 N5 r7 {0 ]4 ]6 L label-current ]# \7 E% R% ~& E
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set-default-shape turtles "car"0 b: t' N, M5 h5 a0 M1 g
# [; X2 X X$ a' ? if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of ": M4 s) z- T) s7 l' n) w/ d) F# u
"road. Either increase the amount of roads "
E3 N4 f5 t% z$ V' J "by increasing the GRID-SIZE-X or "9 D/ s; b. t3 [ G+ T, k. a3 ?+ l
"GRID-SIZE-Y sliders, or decrease the "1 W$ c+ L- H8 M
"number of cars by lowering the NUMBER slider.\n"& W$ Z0 i4 a: k% w5 h2 `
"The setup has stopped.")' D- M \" s$ [/ W
stop% \) h( A% i8 {9 J! Q4 Q) o+ ^
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
0 M( m4 h# @# l- D2 W" \, w5 B crt num-cars1 z! A( {; {3 m1 k8 y
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r0 Z" i* K, d setup-cars9 o" t, q4 t# F' j/ }, U; ]: H3 W
set-car-color
5 I% J2 a! V4 z2 t- {* |: ~ record-data
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;; give the turtles an initial speed
6 C j! f! L0 `8 R ask turtles [ set-car-speed ]
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/ a+ p7 A' D8 V \ reset-ticks
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' e' U, i7 k. i8 a' l;; Initialize the global variables to appropriate values# T3 u% Z. t7 Z3 M- f
to setup-globals; o1 f" e; p& G$ Y5 V$ X
set current-light nobody ;; just for now, since there are no lights yet1 D+ y2 B7 J/ | h0 {
set phase 0/ x$ D; O5 [( h; z9 Q
set num-cars-stopped 0# o" I+ y# u+ M: C
set grid-x-inc world-width / grid-size-x8 p2 i" i2 h6 T
set grid-y-inc world-height / grid-size-y q* ~# O' w$ \: L5 E
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary" i! T, o& l1 Z/ f+ l k2 ` U
set acceleration 0.099
7 u, L! e( S3 z6 zend
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4 ?" P0 x1 K7 H0 k/ d$ {/ i;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
3 \3 k6 s% p- K0 F% m% X;; and initialize the traffic lights to one setting
, G2 r8 X& I8 U. x! \to setup-patches
. c$ q% p) \% ~ ;; initialize the patch-owned variables and color the patches to a base-color _8 }0 H& S) Y2 j
ask patches
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set intersection? false
8 Y+ S, |' o; ?# i+ a1 V9 q0 C set auto? false g* a6 L/ M8 V, G
set green-light-up? true* \# W; f$ h: m. ^0 m
set my-row -1
/ R& J' P( B+ M3 D2 b; p# q set my-column -1
+ E5 t) k3 q# Q2 \1 ^ set my-phase -1
/ K y& Z* |* Y9 e set pcolor brown + 38 m. H6 w% c; M I0 s% i& p
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;; initialize the global variables that hold patch agentsets4 m M: G* {! n% J
set roads patches with
; G5 o2 x4 v& v. P7 B* p [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or- g }& \8 I k2 a
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
, }8 x& _% Y' W g0 D5 U6 o7 b set intersections roads with
- Y* N5 F$ d& f1 }8 v [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and8 P# x: J' Z/ B- ?: E0 Y( x
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]# z9 x& X# {! I( r6 j4 @1 ]0 R, @
1 Z$ S9 p1 C7 k) h8 z$ X; t/ ^ ask roads [ set pcolor white ]$ G- M& }" n4 y$ A+ }
setup-intersections- L R( q: ^& ?% G$ [0 N; s- T
end ?6 I; M& a4 |7 ~4 }: P
其中定义道路的句子,如下所示,是什么意思啊?
# g& @7 a8 j, L; Y set roads patches with" Z/ Q+ J7 {; \6 a {
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or* M+ |; @" t- N& t$ y1 W
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]% a* d: K" L2 q* U6 B. @
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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