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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 K; }% k; l/ \& onetlogo自带的social science--traffic grid这一例子当中,
! s& ^# y% X( Uglobals0 \0 {( r1 q8 Z% \) Q
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' k, _ t' E6 c9 `+ V9 I grid-x-inc ;; the amount of patches in between two roads in the x direction3 r+ M: S, ?3 d3 Z2 Q3 W9 p
grid-y-inc ;; the amount of patches in between two roads in the y direction
" m" y+ Z& ?$ S. _+ M1 F acceleration ;; the constant that controls how much a car speeds up or slows down by if# M' S( \0 X% E/ V9 T. n2 a
;; it is to accelerate or decelerate
# O9 `! R$ b X6 N0 r9 x phase ;; keeps track of the phase
9 b* L# H, v; W v7 d num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
/ o) H) a$ J, N current-light ;; the currently selected light
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4 ` N+ d4 A1 g; @2 E ;; patch agentsets
! O( r( @" e% d& i intersections ;; agentset containing the patches that are intersections
( I$ |7 A. @, B4 {1 H, I roads ;; agentset containing the patches that are roads$ G$ c( z: e5 Q/ O, x6 i( X8 R7 t
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turtles-own
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speed ;; the speed of the turtle: P0 b, u. o8 Q# j$ c) l
up-car? ;; true if the turtle moves downwards and false if it moves to the right
E u4 M7 W$ p" E( {8 M: ]$ @ wait-time ;; the amount of time since the last time a turtle has moved
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& J7 O1 e/ l& i5 Qpatches-own
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' W9 t' S/ Z) W: K intersection? ;; true if the patch is at the intersection of two roads
1 p/ m" B1 Y' O* v& h. ` green-light-up? ;; true if the green light is above the intersection. otherwise, false.* G/ v/ P W1 y* \# O2 Z
;; false for a non-intersection patches.1 S1 t7 U) q( M) \. U: X
my-row ;; the row of the intersection counting from the upper left corner of the
" }2 M& W7 H3 n" V$ a; S; L ;; world. -1 for non-intersection patches.! L& t4 ^3 W! T9 I! y" w
my-column ;; the column of the intersection counting from the upper left corner of the
* S2 K+ ^+ x( Q) w9 W8 P8 c ;; world. -1 for non-intersection patches.
% f0 E4 r8 a0 N1 D" n4 u4 R my-phase ;; the phase for the intersection. -1 for non-intersection patches.
8 L. j* _; H2 k! i. l; a auto? ;; whether or not this intersection will switch automatically.
7 T( v; C% w/ `; ^# q ;; false for non-intersection patches.
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3 z) u: r* E3 W4 p: H, K+ i# C;;;;;;;;;;;;;;;;;;;;;;% q& z/ w7 h# l$ f
;; Setup Procedures ;;
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;; Initialize the display by giving the global and patch variables initial values.
& P2 c4 Y) o0 D;; Create num-cars of turtles if there are enough road patches for one turtle to
& m% x5 i) w# t9 A4 s* b* };; be created per road patch. Set up the plots." `8 K' \" }( l
to setup8 C) O, {( {( s7 |/ ^
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setup-globals
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% h. Y" g3 r5 n) _7 x& S3 B ;; First we ask the patches to draw themselves and set up a few variables
; X' R( ~7 O' O2 k& g; d setup-patches
. O5 X9 W/ B5 C+ \3 r2 A& c/ J7 D make-current one-of intersections
4 w- g( F5 \0 U label-current/ j6 t5 B0 z2 w2 @/ \
5 s4 A; P& h" f# Q; U" G7 g set-default-shape turtles "car"+ s+ s7 Z* I5 b: @7 @# h7 M( {2 T
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if (num-cars > count roads); t) S8 W) y0 J8 ]% d/ y$ c! O
[
, g. R1 r0 ^2 X! D. ^& i user-message (word "There are too many cars for the amount of "
" L4 n, L/ O' \; G2 j1 s3 g "road. Either increase the amount of roads "7 ] v2 J) J& B( @0 C
"by increasing the GRID-SIZE-X or "
; h2 ?7 h+ _! A9 d0 K" S "GRID-SIZE-Y sliders, or decrease the "
* I0 K9 ?+ m4 A$ l: `. f) g7 } "number of cars by lowering the NUMBER slider.\n"
: A% b4 E2 I8 ]; x3 S0 @ "The setup has stopped.")8 {& s$ \2 w4 e! u1 u
stop$ R. `, K& w7 O6 b* E( N0 m
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
4 \( M; s; x2 P: Y# E crt num-cars$ ?5 T$ K" [# \+ V( @
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" X! [) r4 R; K setup-cars; B6 \, l9 S/ d
set-car-color
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;; give the turtles an initial speed
' H2 l/ v9 H$ Z. V+ x0 h ask turtles [ set-car-speed ]; H+ `% \$ S9 s& y! e
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reset-ticks
& V& `% S" \* ~ v0 _6 Tend
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;; Initialize the global variables to appropriate values. F, i; j! Z: F& k5 |
to setup-globals
) b. A% W: h: e$ Q6 X set current-light nobody ;; just for now, since there are no lights yet# J6 y' E: W" }/ z9 N5 o2 E! S# X
set phase 0$ W( d: I+ ~6 }) L1 I
set num-cars-stopped 0
, N2 m% l5 H3 C7 m) Z set grid-x-inc world-width / grid-size-x6 F$ I$ c# A8 e% c$ N
set grid-y-inc world-height / grid-size-y x0 ^% C! r3 H8 d
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
7 u. g, _# r5 c! x9 M set acceleration 0.0993 }4 N7 C6 k6 E7 |4 y
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
' Q6 E8 u3 ]6 x2 p;; and initialize the traffic lights to one setting
# l2 h8 D3 R* U6 E, J6 `+ K4 ?to setup-patches; d' z3 A* F3 _. k
;; initialize the patch-owned variables and color the patches to a base-color/ n) o1 r8 K. b0 Q
ask patches
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set intersection? false, S# n9 ^9 [/ I" ?0 u
set auto? false
! z$ f4 i9 P5 u& [4 c; o: t/ I U set green-light-up? true
& ~. ^5 E8 Z% a4 ]/ |7 ` set my-row -1
1 r3 {. {% t6 H: A0 g2 K6 y set my-column -1
' Z3 z0 [0 Q, P3 s# h. x" l# ? set my-phase -1
. I8 |) Y* ^; e3 o% _ set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets* @" N3 I _ D2 G& l+ a# c
set roads patches with- n" E3 m7 ?$ \' n
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
/ z$ m9 {- Q4 ? (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
1 \ v6 A4 u& [ `& w2 l; Y1 O% H set intersections roads with
, u q" N1 M/ u w% Y5 V; r [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
' h7 V5 c. M0 N' C/ m! O; n4 _: ]$ |0 @ (floor((pycor + max-pycor) mod grid-y-inc) = 0)]" z& Y1 i- V( h$ \$ r! l2 `
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ask roads [ set pcolor white ]
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end6 y' {& W. u, w, L* X
其中定义道路的句子,如下所示,是什么意思啊?
- @6 Z* B% e# s( Q set roads patches with" x/ g( |+ A" T2 p( e
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
0 r! Z0 M% [. N (floor((pycor + max-pycor) mod grid-y-inc) = 0)] W( q/ e3 ], ]4 @6 }2 c/ \! F4 ~
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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