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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。3 d2 Q- r7 T2 B' c. M( ]% h6 I
netlogo自带的social science--traffic grid这一例子当中,
: }; b9 d" k/ E- S' ?( nglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction ]2 ]9 m# d) c [
grid-y-inc ;; the amount of patches in between two roads in the y direction; [/ f' P1 W' @( {0 z' v+ c
acceleration ;; the constant that controls how much a car speeds up or slows down by if
8 }9 M3 }' ~7 ~& m* N7 O9 P( o; [. b ;; it is to accelerate or decelerate
3 W. `* Y/ k% T( b phase ;; keeps track of the phase9 V% a( P' z7 t+ d
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
8 k# W; i8 [; H/ E current-light ;; the currently selected light3 i$ X5 q* D8 b! N# ?% Y
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;; patch agentsets5 `6 ~: W5 D# \$ ]; B
intersections ;; agentset containing the patches that are intersections
$ U$ Q! g3 N! t; C roads ;; agentset containing the patches that are roads
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turtles-own
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2 z9 Q0 K! Z/ G+ F; W) ] speed ;; the speed of the turtle
, a, H1 [0 W+ A up-car? ;; true if the turtle moves downwards and false if it moves to the right
7 `( F! y, X% x" Y( K: b! t) I$ j wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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9 [6 J( @8 b$ c# j intersection? ;; true if the patch is at the intersection of two roads
+ j. v4 D; b/ n/ H- H( N green-light-up? ;; true if the green light is above the intersection. otherwise, false.# T9 x( E0 `$ I, ?8 q' F
;; false for a non-intersection patches.
6 O" S$ a2 ~* N5 k, Y+ w my-row ;; the row of the intersection counting from the upper left corner of the3 r# ~8 A5 \: V6 X0 l
;; world. -1 for non-intersection patches.
7 G9 ^& d; y9 O* Q4 k+ i my-column ;; the column of the intersection counting from the upper left corner of the% x0 F+ B# _# g" G: S. u
;; world. -1 for non-intersection patches.. u% h# O" t5 H+ |3 l+ S
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
5 s3 m& M: }* C+ P2 e auto? ;; whether or not this intersection will switch automatically.
, q% k* b2 K' \- p7 D$ u ;; false for non-intersection patches.7 m% k& i3 Q% |
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;;;;;;;;;;;;;;;;;;;;;; F! s, n5 u5 W/ i
;; Setup Procedures ;;
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;; Initialize the display by giving the global and patch variables initial values.
5 K" q- V3 _$ }( y& p;; Create num-cars of turtles if there are enough road patches for one turtle to
; }9 F ~+ Z7 ^6 T3 F; j( v;; be created per road patch. Set up the plots.
! ] L( X! d% q& L4 xto setup
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setup-globals
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2 F3 V3 Z+ i- q' V; w; Z) H% o ;; First we ask the patches to draw themselves and set up a few variables: T0 s7 T; E! H8 }7 i" S
setup-patches1 h& I8 [' {8 W4 t4 W/ y) @
make-current one-of intersections
6 i0 Z$ h `, f. c label-current
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* U3 J7 C6 V2 U& L. J) X set-default-shape turtles "car"& k) J% d, `; Z/ a$ N+ W
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if (num-cars > count roads), M/ g+ u; M1 r$ U* n! W* W1 z
[
/ h& F. `4 m1 X6 T, q% l user-message (word "There are too many cars for the amount of "# D$ p, r/ N0 b! h1 D2 s; _
"road. Either increase the amount of roads "! a& Y0 l+ h0 z G# f; q
"by increasing the GRID-SIZE-X or "
4 J3 r7 v9 T# Z; x% _. j# P "GRID-SIZE-Y sliders, or decrease the "
5 k( }% z. f# w7 I8 T) } "number of cars by lowering the NUMBER slider.\n"
3 L/ V1 [, {5 e "The setup has stopped.")
- s% `2 v p8 I4 {# r% j% P: h stop. [& c# `/ _% {
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# D- E# ^3 S3 B' {, s" Z ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
2 m0 C: h1 v: ` f" W8 | crt num-cars* z; I" k0 t$ C& g# r
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setup-cars; p; s, e" b0 O P
set-car-color
9 C+ x& i- @3 ?" t9 g+ z" A2 {2 H record-data
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;; give the turtles an initial speed
( E$ A7 \0 u# a ask turtles [ set-car-speed ]
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4 Z+ F5 }6 ^& Z2 q; T reset-ticks* t% |+ [& w E. U; c- q% g
end
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! P) m( p. n% k4 l% Q, z;; Initialize the global variables to appropriate values8 x0 U; ~7 \ R0 X, p+ M
to setup-globals( U5 o s) j) P/ B" ~. e1 G
set current-light nobody ;; just for now, since there are no lights yet
8 O w; k4 S. K: f! [ set phase 0: v/ i u+ @' E/ i( ]
set num-cars-stopped 0: I7 v% E* _) J0 ^' M' g! U
set grid-x-inc world-width / grid-size-x
: W8 F$ v3 d; M u+ z1 v2 I6 W set grid-y-inc world-height / grid-size-y* y4 z, X& |) Z7 G: S
# M+ q) M1 X6 N% {$ `! ~+ b ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary$ k/ T8 G; |' V6 m4 @1 E0 V" W
set acceleration 0.099
/ x( p( ^8 g7 G- F2 R+ nend
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+ F& b* `3 G& I, M;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
1 [6 y9 m; u) ~;; and initialize the traffic lights to one setting
D4 N8 D) n$ z1 X) u/ Eto setup-patches# J U) c: _9 `; F
;; initialize the patch-owned variables and color the patches to a base-color
% ?* n; A) C+ {+ p2 x- y% t+ b ask patches/ c1 _( z* X" ?) i% T
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! I( B3 n& V6 Q set intersection? false
7 _1 `- v; |! a3 @2 s/ h! K set auto? false8 a8 C; f9 l) O6 Q- J$ a, `- O
set green-light-up? true
- ]$ l7 u3 W; W2 R; M( P! d set my-row -1
" @$ a* \. d+ p9 p set my-column -1
% b0 ~% Z5 {5 t* L set my-phase -1# U' @- x8 {, h0 ~
set pcolor brown + 3# M% i3 f6 g) `; A" N) o
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C2 G* Q% j5 X; n4 e" G l ;; initialize the global variables that hold patch agentsets4 G& T8 Y+ F9 C
set roads patches with( e1 Q, C# n+ C. v
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or, `! T' e4 z, U. |. ]+ p" E
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]1 M b9 t$ `6 A3 s. a: q0 b& H/ a* e
set intersections roads with: r/ o& L8 Q' |2 A! e+ X& G
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
3 H: h2 m% i5 J8 D' J* M (floor((pycor + max-pycor) mod grid-y-inc) = 0)]2 [ {& F- o3 u! z" G0 [( G1 t
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ask roads [ set pcolor white ]+ m8 E2 V) @, k, H6 d
setup-intersections
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! a( P: x1 |5 v3 N+ ?( _% r其中定义道路的句子,如下所示,是什么意思啊?, R/ O$ ~3 c4 |+ p
set roads patches with
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(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
4 j6 P! H! Z2 _8 m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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