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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。' E( |7 O+ F; P w, b; Z
netlogo自带的social science--traffic grid这一例子当中,
$ \9 v6 Q+ |- N4 |% O9 p7 `+ t! hglobals; P& K+ M" U/ n2 W! h
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grid-x-inc ;; the amount of patches in between two roads in the x direction
& C1 z3 ?' `) X' q/ n. `- T grid-y-inc ;; the amount of patches in between two roads in the y direction
2 ?/ t6 _3 T/ k& S3 S acceleration ;; the constant that controls how much a car speeds up or slows down by if
. }( l% m% S8 r7 D7 [ ;; it is to accelerate or decelerate0 z# s9 n! L9 Y, n
phase ;; keeps track of the phase
! k+ p5 b. |) g* O0 o2 q2 C1 [+ q, E num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
9 i( e( W) r' ~2 C" n current-light ;; the currently selected light
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;; patch agentsets
% P4 s+ l" T4 ~$ s* K: r" E intersections ;; agentset containing the patches that are intersections8 p: ]6 z+ j* e6 g0 v3 g9 E
roads ;; agentset containing the patches that are roads
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turtles-own
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speed ;; the speed of the turtle
+ r9 _$ t; {, |2 Y1 _! P3 O, b up-car? ;; true if the turtle moves downwards and false if it moves to the right
0 C9 {) q+ w$ b5 X3 X) r5 J wait-time ;; the amount of time since the last time a turtle has moved
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patches-own) {- |) h2 H- h) H
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7 n6 w- Z' |! V6 @5 B# v' K intersection? ;; true if the patch is at the intersection of two roads. d- ?+ O2 i/ R+ ^9 I
green-light-up? ;; true if the green light is above the intersection. otherwise, false.% a% M) u" P* w; J4 ?) s4 M
;; false for a non-intersection patches.
# {5 C a- @2 S my-row ;; the row of the intersection counting from the upper left corner of the
2 E6 l# z/ m& n- j/ j) e* j ;; world. -1 for non-intersection patches.
t( l5 \, Y* t& H, z; M: Y9 z+ u my-column ;; the column of the intersection counting from the upper left corner of the
# Y- `- _- g5 r i q ;; world. -1 for non-intersection patches.6 } O( ?9 H ]2 ]
my-phase ;; the phase for the intersection. -1 for non-intersection patches., K% \# Z% }% b {
auto? ;; whether or not this intersection will switch automatically.
+ q+ |4 N- e4 c ;; false for non-intersection patches.2 H# x1 T0 F4 u8 U
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;;;;;;;;;;;;;;;;;;;;;;; I" `2 `: r) c3 n( `
;; Setup Procedures ;;
6 K Y$ s/ i3 Z) M! r' ~. g8 N;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.5 O3 X+ W8 w% V5 Y6 ^
;; Create num-cars of turtles if there are enough road patches for one turtle to
! t) c% S8 z' P9 z6 ~;; be created per road patch. Set up the plots.
8 L7 [$ s3 P. n8 `& s% nto setup- q; M+ T5 G4 U3 i# U. n0 y1 u
ca
; u4 O) w5 n0 M- p/ o; }; }- C3 g setup-globals a/ G$ z0 F+ o# g
' N3 S m8 F& Z# x' a( C1 j ;; First we ask the patches to draw themselves and set up a few variables$ z+ b3 L5 F# \# o( X9 i Z
setup-patches% a* R) q- v; Y0 `7 Z5 `8 K& d
make-current one-of intersections! ?% r8 Q) ~9 M& V+ v: a$ t
label-current$ p; N; [1 R. x) o& g
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set-default-shape turtles "car"% \; O& _ K4 }, d( }
: q: S, [; ~! `/ E, L- T if (num-cars > count roads)5 N' M9 F( M+ `; o8 p
[
& Z. O$ k* q* d: s% G user-message (word "There are too many cars for the amount of "5 ~0 y# A7 k3 C5 W0 C" t- S/ U
"road. Either increase the amount of roads "
4 J3 P6 J, z4 E! i& \ "by increasing the GRID-SIZE-X or "2 u3 r' r3 a2 y1 w; v0 K
"GRID-SIZE-Y sliders, or decrease the "
. `, {! a) Q/ P "number of cars by lowering the NUMBER slider.\n"
7 Q# a8 W2 l7 N* R, \* @$ z3 z "The setup has stopped.")
2 {8 {" q* A$ w9 t7 v2 } stop
$ t$ X& X, n/ t0 k. F! _ ]
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color2 y1 U( t N, V0 d
crt num-cars
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setup-cars/ K" P: S, o6 x. e& F' }: W2 F
set-car-color
* x; z- O3 s; c! C: [, N record-data
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;; give the turtles an initial speed# }9 W. M8 M" t$ O2 X
ask turtles [ set-car-speed ]
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reset-ticks
/ d0 \5 {' M. T$ J- \* i$ Cend
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;; Initialize the global variables to appropriate values
5 J$ L. t( _+ |& x) w! f0 G: G9 g, zto setup-globals
9 F8 R8 w2 k' E2 W& k& H set current-light nobody ;; just for now, since there are no lights yet
' Q$ ?- u! C6 ~2 a set phase 0
2 }) g7 N& _0 u1 L% n" R4 @ set num-cars-stopped 0% x# c) [. ]7 i" D$ E: C- t. ]
set grid-x-inc world-width / grid-size-x% E( ]* S; h7 _: F! O3 ^
set grid-y-inc world-height / grid-size-y9 Q5 U( c9 L7 L" ]- U0 w
# a4 T) ?4 [: w
;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary( S* @, s, P6 k3 G' R1 U0 E. K
set acceleration 0.099
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
0 G# w- v* x9 D0 P;; and initialize the traffic lights to one setting
1 q [% m- C9 o$ P: pto setup-patches
8 o7 \! W1 _$ g8 ^% P; m# Y ;; initialize the patch-owned variables and color the patches to a base-color. ^. b4 R1 s! v8 v7 ~+ U+ i0 e* D
ask patches" C8 X, n" b" d5 q
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: q' R3 G$ V6 T, q+ E6 R set intersection? false
5 H4 y, y9 f1 g5 j5 y set auto? false& y: L5 t2 V' Z( \" d; k
set green-light-up? true
5 X, W+ M, i3 g% h5 e$ \7 t+ q6 \ set my-row -1
5 e" X: G8 b' k! [9 ]1 H set my-column -16 Z& {* Y+ w' {6 L9 m
set my-phase -1% N/ `2 h# v0 k* N0 {
set pcolor brown + 3" B) z H% I' Q( h/ w: Q
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1 Y1 h, b$ R3 M. ]6 ]1 ? ;; initialize the global variables that hold patch agentsets
, B' M" @. v7 M+ H set roads patches with
+ c" C6 t$ A4 n( { p. d, _6 I& T [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or; C4 v: U T- o& l: _2 S/ ^
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
% `0 v9 k/ i1 S5 Q% J set intersections roads with6 |% }: X1 g1 c9 u
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
! r# O" i$ O, c: }8 d (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]# `2 m4 H3 L6 i$ g$ K
setup-intersections$ } y+ ^+ _9 c; B( G
end
! S& @8 W1 i; E+ Z其中定义道路的句子,如下所示,是什么意思啊?
: G' Z& P( x% Q; l5 I3 i! p/ j set roads patches with
( ~$ a) d: P8 e0 F5 c [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or7 d y, B% `4 B* t7 ^# m e, n
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]0 @# ~0 `. y1 [/ j7 O 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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