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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。
$ _0 v9 p2 X, ^3 f3 ~( ~- Enetlogo自带的social science--traffic grid这一例子当中,' U9 J& H% Z& X2 d X; Y
globals; B7 f. o& z/ Q
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grid-x-inc ;; the amount of patches in between two roads in the x direction" L, U5 h$ W$ R5 x/ l ?# _( p
grid-y-inc ;; the amount of patches in between two roads in the y direction) d8 }' \) x" o0 Y
acceleration ;; the constant that controls how much a car speeds up or slows down by if; W6 h7 f- u; H/ c1 `- w+ W
;; it is to accelerate or decelerate( a V4 {2 O5 e
phase ;; keeps track of the phase e9 m9 [9 f; I) B: K
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
2 e% d3 u5 A- d current-light ;; the currently selected light
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;; patch agentsets" B6 s; G0 {* l' m' \, t2 |. l5 O
intersections ;; agentset containing the patches that are intersections9 t. F. I' s+ [. p% F( ^7 f
roads ;; agentset containing the patches that are roads3 z2 s6 B7 B5 @/ I+ h) S- N! i
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turtles-own
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) B$ i: y( K4 Q: R speed ;; the speed of the turtle
- J( L* b2 j8 L" J# F up-car? ;; true if the turtle moves downwards and false if it moves to the right: |0 d7 \4 C: g- {8 i5 x
wait-time ;; the amount of time since the last time a turtle has moved" ^3 `7 l+ F7 t( N( @7 M" ?
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# w9 v2 j+ f7 i6 }6 u# bpatches-own A6 b9 E9 [) n; _ b
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intersection? ;; true if the patch is at the intersection of two roads( }3 }4 r- @* v9 b
green-light-up? ;; true if the green light is above the intersection. otherwise, false.' Z& a: {& c+ X1 n% S& J
;; false for a non-intersection patches.
! S$ s' u; x: |4 `1 s7 ?5 h my-row ;; the row of the intersection counting from the upper left corner of the, ^+ ?8 i- f4 Z" T; o
;; world. -1 for non-intersection patches.
/ E3 a6 E) R3 I+ O9 | { my-column ;; the column of the intersection counting from the upper left corner of the s3 G1 B$ |% L5 H
;; world. -1 for non-intersection patches.
8 M: m1 D8 i+ y my-phase ;; the phase for the intersection. -1 for non-intersection patches.' v1 ]. `/ O% n0 X! W: u
auto? ;; whether or not this intersection will switch automatically.- l; f1 j; \; `
;; false for non-intersection patches.
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/ U8 J% q3 @, `' a6 k ?) Y' X;;;;;;;;;;;;;;;;;;;;;;" g3 u0 n, R- @; e% W
;; Setup Procedures ;;
9 _8 l9 V6 r; q: Q d+ Y2 U;;;;;;;;;;;;;;;;;;;;;;
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; \0 F1 _* l/ N1 ^$ W) D;; Initialize the display by giving the global and patch variables initial values.
- W6 n8 s1 w/ C3 E" _% H;; Create num-cars of turtles if there are enough road patches for one turtle to
" i# g. i3 o0 { w- [2 c4 i;; be created per road patch. Set up the plots.
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setup-globals
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! d. E6 {: `( x; X ;; First we ask the patches to draw themselves and set up a few variables: S# H! W2 `: H; [$ o3 m% z9 F
setup-patches j1 d6 Y5 U0 `" V
make-current one-of intersections
; A! x+ }# X$ w label-current' v- B+ X+ N3 ^
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set-default-shape turtles "car"% \9 q& O* D0 K$ @# _' z
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if (num-cars > count roads)( j! P5 J: |; s6 @/ J
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+ F l( m* I! a3 Z1 b user-message (word "There are too many cars for the amount of "
2 [$ f5 l( S6 T, T "road. Either increase the amount of roads "
( C# ?0 K9 x2 Y$ D; b "by increasing the GRID-SIZE-X or "2 [! \2 ^8 z; A% z- {! J
"GRID-SIZE-Y sliders, or decrease the "
; S4 |* p7 M. O$ M% _3 A "number of cars by lowering the NUMBER slider.\n"
6 Z5 I6 A6 b8 Z( [4 t "The setup has stopped.")
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
5 p, y V' n" e; g4 }- y! F1 b crt num-cars
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setup-cars
' F8 E4 I4 H0 W( q3 }; U: I set-car-color
. e3 g+ S# s7 w9 U3 x# v record-data; U% i2 |1 N; t
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9 L$ p9 J- L0 N2 y5 f+ ?! ~& W& w ;; give the turtles an initial speed3 K% u0 f; {$ o$ g# h& I
ask turtles [ set-car-speed ]
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reset-ticks
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;; Initialize the global variables to appropriate values) d- f1 ]: F( o
to setup-globals2 E; I- Q$ L5 [, N3 x: A
set current-light nobody ;; just for now, since there are no lights yet
( h* o$ o8 J) A% a1 d' u set phase 08 k5 h# I( _4 n- u
set num-cars-stopped 0
# V/ L9 h7 m& v: o) p. P set grid-x-inc world-width / grid-size-x# H' s& n: c. o! ]( k ~. Q7 W
set grid-y-inc world-height / grid-size-y
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( H2 l8 V5 H, i+ h ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary$ @' P3 D0 z9 u* I! k" c1 O5 h* o
set acceleration 0.0996 a3 p% E5 t4 I* b7 F* v
end
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+ Y2 c* k* F* C2 P) F;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
8 u1 z8 f0 e# Z' O2 N4 `; o9 h;; and initialize the traffic lights to one setting
# V: o( Y* \& C$ Z6 ~to setup-patches) w6 Y8 n( a* M5 T# f5 Z. c
;; initialize the patch-owned variables and color the patches to a base-color! \) {* A! ^* s$ o& U) a
ask patches; O3 F4 i1 H) m% S5 m! \
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. @1 E0 l1 [# ]8 f: l* n0 W set intersection? false" x9 `3 o. y z' s
set auto? false d: W3 C/ R2 n" ?& S, ^4 z8 C
set green-light-up? true" k6 |( b0 a: {9 U
set my-row -1, V9 Q! `8 l, X9 u/ c9 l
set my-column -1
2 f- G. q& Z; Z7 } set my-phase -13 |; O9 C# N# A6 s' S9 r
set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets
. t/ Z D4 [( w `2 \9 Q: E" X, g set roads patches with
; S' E7 E2 Q" v6 m$ t4 T [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or: y5 L+ a# o% X/ t- I `8 k. h
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
) I/ H* ]& h. D. j# g" y0 w: c4 F set intersections roads with
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(floor((pycor + max-pycor) mod grid-y-inc) = 0)]. [ f: v! S/ W7 l$ L
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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?& e7 G8 H" C- G0 h8 k* G
set roads patches with
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(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
$ A( q! @# p: x. l+ D" i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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