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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。
. L3 E2 e, `7 C( W- y- b$ a3 pnetlogo自带的social science--traffic grid这一例子当中,
2 r! L! Q1 V! T# u$ pglobals* M0 z" p1 p" d, ]
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grid-x-inc ;; the amount of patches in between two roads in the x direction
0 {/ q% _5 V+ h* F# g2 @ grid-y-inc ;; the amount of patches in between two roads in the y direction, f0 b% o( A8 X( r
acceleration ;; the constant that controls how much a car speeds up or slows down by if/ W( S9 n: A# w4 Q5 y
;; it is to accelerate or decelerate# F X5 @# K) ]% l9 [) h
phase ;; keeps track of the phase
* o& k" s* F: Z5 Q6 L) E4 s n num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
. g' r; l; H4 @ current-light ;; the currently selected light" S& M) T5 y9 ^8 _. `* E9 F
2 z8 y+ i5 ?. @0 h ;; patch agentsets
; v: D# y, |/ a- ` intersections ;; agentset containing the patches that are intersections H F; Y3 ]8 |% _+ `# ?6 x3 m
roads ;; agentset containing the patches that are roads
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turtles-own1 `$ u" J" G9 C/ @2 R! D0 Q
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speed ;; the speed of the turtle, j0 t: O: W0 p% M
up-car? ;; true if the turtle moves downwards and false if it moves to the right9 o- m/ n, q9 ~* e
wait-time ;; the amount of time since the last time a turtle has moved
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% G' q8 ?5 {; upatches-own
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intersection? ;; true if the patch is at the intersection of two roads9 |5 r/ M' O7 i* B# c* L& L
green-light-up? ;; true if the green light is above the intersection. otherwise, false.- B8 K0 |& p7 c3 A% G
;; false for a non-intersection patches.
" Z: F5 K# H3 q( p! {% N2 y# m2 _ my-row ;; the row of the intersection counting from the upper left corner of the
0 A+ c( M( W) ~7 V ;; world. -1 for non-intersection patches. @6 x; j: v3 y3 f, v
my-column ;; the column of the intersection counting from the upper left corner of the% |' f, I) \5 }
;; world. -1 for non-intersection patches.
3 c: `/ n$ g5 f6 N) Z. { my-phase ;; the phase for the intersection. -1 for non-intersection patches.
4 o# X" P0 H# @, Y8 A. @ auto? ;; whether or not this intersection will switch automatically.$ t( @' |1 Y" M9 G: C" c/ R
;; false for non-intersection patches.
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# W% V Z% [4 R# r. j; x4 N1 F;;;;;;;;;;;;;;;;;;;;;;
+ c, F# N, r# }, Y;; Setup Procedures ;;5 t- g9 _7 k' D, i! u/ {+ f6 t1 e
;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.
$ @7 P$ Q% B h! g) y3 n3 U) C5 E: S;; Create num-cars of turtles if there are enough road patches for one turtle to& s T2 H7 j, y# p- n% a& n
;; be created per road patch. Set up the plots.7 {# K" }% j. @- z! p6 x
to setup5 b ?7 }- p4 {- W3 H# O, J: x. k
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setup-globals
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;; First we ask the patches to draw themselves and set up a few variables
6 Y# n. h+ n, u- p" p) u, f. i setup-patches
6 J7 q8 w0 N/ v0 r! ^0 G( t; y make-current one-of intersections
) L+ F! e" @! u/ z" [7 m% ^; ] label-current ^2 o! ^8 x1 ^& }
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set-default-shape turtles "car"
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/ m5 N2 S* D6 o if (num-cars > count roads)( u' [7 u: |9 U) B+ H$ c6 _# H& z
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' u' S; \$ q& j/ g" M user-message (word "There are too many cars for the amount of "
% a- R1 K* I' \) x" f3 u n: ]( I "road. Either increase the amount of roads "; V. c* O" u+ h1 M- L: r/ c
"by increasing the GRID-SIZE-X or ": t; L/ s: Q$ w& h4 y8 c q
"GRID-SIZE-Y sliders, or decrease the "
|2 w) a" a8 P) D "number of cars by lowering the NUMBER slider.\n"
5 i, s- R9 d6 d, n" _ j: ^/ j "The setup has stopped.")
9 u0 ~* F; j- A i! x, D stop
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8 g( h* r ]$ |5 Y ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color6 S6 |4 J% m9 R. D+ E
crt num-cars4 ?( U1 n7 W9 G- w
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set-car-color e1 e6 b( a. d
record-data
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$ q" j0 j6 g, X ;; give the turtles an initial speed
+ a- z0 [; y1 X- @( A ask turtles [ set-car-speed ]
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reset-ticks
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# G U7 t1 d8 \: M4 P. T;; Initialize the global variables to appropriate values
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2 r" G1 ]. t) q8 N3 Y1 y. b set current-light nobody ;; just for now, since there are no lights yet' c: [* M( d1 M! ?* g5 e l
set phase 0) t( v9 l7 ]' j4 V
set num-cars-stopped 0
+ x: O8 @" z1 [ g# q Z" s. M+ T set grid-x-inc world-width / grid-size-x. Z6 V7 t3 ?; E" p. h9 |
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
- V* U" Y w1 R+ ?7 F4 Q$ q set acceleration 0.099' Y: L) E2 d. @4 @1 G! b% D
end
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4 H0 H0 y$ w N' J7 y3 x9 S/ D;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
- E1 r( P6 l8 _;; and initialize the traffic lights to one setting/ o+ u/ r+ w$ q; ], q) ]' B
to setup-patches# J8 e9 V4 o: Q
;; initialize the patch-owned variables and color the patches to a base-color! Y) `3 O5 {! i* n5 K* O6 u" O
ask patches5 q0 W' S0 ?" t% S
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set intersection? false9 X5 O9 i7 L% H$ ~5 q% Z4 W9 ?
set auto? false8 }* F# e! l4 v9 I6 Z
set green-light-up? true! P G; E$ [# m/ S- Z' _: ~
set my-row -1
6 G: v9 L [! F0 X8 b+ E set my-column -1% C8 N# ]+ h3 ]
set my-phase -1
9 X7 Y3 K! R( b3 d$ O: O set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets3 C% B* o' }) ^2 C) U$ D
set roads patches with0 g2 r# I! N6 t8 o x8 i
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or+ C( V; ?! ^+ E
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]) s0 h* u$ z- b) K" C" U+ U
set intersections roads with+ p' M/ N- V& L0 q6 p) J
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and' m* l/ ^7 y, ?
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]1 B5 ?8 |/ i- G4 N" D
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ask roads [ set pcolor white ]
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其中定义道路的句子,如下所示,是什么意思啊?6 \- ~4 x1 g W% S) [/ a+ U
set roads patches with
0 D9 \+ z Z5 b [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or7 ]) u2 p+ w6 A% C
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
~& y) i$ R& A' b- {/ c- 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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