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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。) B% c8 X8 r( M
netlogo自带的social science--traffic grid这一例子当中,
- Q. V- b4 \. ^5 E; p) Zglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction
9 \! C8 W9 T/ y grid-y-inc ;; the amount of patches in between two roads in the y direction: o/ v: q! I, s) T% N3 F
acceleration ;; the constant that controls how much a car speeds up or slows down by if) g1 u7 X" K! O& z" @
;; it is to accelerate or decelerate; P6 Z- Z9 V) ]- D: q0 P2 P! I1 P
phase ;; keeps track of the phase+ m# f3 r: e! E% h
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
/ {2 b1 `8 B5 z6 H current-light ;; the currently selected light
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" H' {% \) g S6 X) j ;; patch agentsets+ z l6 P# l: o; L8 d
intersections ;; agentset containing the patches that are intersections/ U0 J+ T6 C% o+ b
roads ;; agentset containing the patches that are roads
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turtles-own
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speed ;; the speed of the turtle
3 B9 w' t } ?0 q/ H+ q up-car? ;; true if the turtle moves downwards and false if it moves to the right6 X& L+ d) x- J; O2 P& D% A
wait-time ;; the amount of time since the last time a turtle has moved
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2 j! g0 F V4 r3 a% j/ s& hpatches-own7 i! m' D7 F9 ]0 @5 x _. o
[
/ R& v. N8 x4 c. i0 b0 L1 p intersection? ;; true if the patch is at the intersection of two roads6 [3 f9 h2 {# m! ] a- }
green-light-up? ;; true if the green light is above the intersection. otherwise, false.; q: g4 i% D/ e, z
;; false for a non-intersection patches.
% u) i! p' {/ M# J8 c( ^ my-row ;; the row of the intersection counting from the upper left corner of the
. R. f* z2 Q7 p; |; e/ V ;; world. -1 for non-intersection patches.
Z# L/ {) s1 L# G2 h+ O, e1 ^. n my-column ;; the column of the intersection counting from the upper left corner of the# Y8 Q5 Z1 P- l
;; world. -1 for non-intersection patches.
: ?6 q1 V) _: ?' T! A2 z/ v; u my-phase ;; the phase for the intersection. -1 for non-intersection patches.
( Q( k' n" X8 ^4 e. N auto? ;; whether or not this intersection will switch automatically.
" ~& ], b# C0 Q1 v5 K$ s ;; false for non-intersection patches.- g0 X/ n1 c# R" `% o
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- a1 H. |% B8 g3 q/ Q;;;;;;;;;;;;;;;;;;;;;;. S: f7 K4 u8 I
;; Setup Procedures ;;
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; l3 ^" P* `6 ^2 Q9 _- f. `;; Initialize the display by giving the global and patch variables initial values.0 M" m$ H4 A p$ M% J- i3 Z! Y, o
;; Create num-cars of turtles if there are enough road patches for one turtle to$ t' R9 z4 P# r2 B
;; be created per road patch. Set up the plots.4 B" {- x/ Z/ o# ]
to setup
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setup-globals
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;; First we ask the patches to draw themselves and set up a few variables8 R( O1 g+ u0 E0 N" U
setup-patches! P1 |7 I- ^0 P- g! C. ?, k
make-current one-of intersections
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0 P& X7 R) Z% V& j' B set-default-shape turtles "car"
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9 w/ l' x4 j6 C, P6 F C* S0 K% z if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "0 g8 i& H) d- ~% V
"road. Either increase the amount of roads "
p2 @( l/ H' D% K8 B' ? "by increasing the GRID-SIZE-X or "
% f6 ~9 ^, s% ~- { "GRID-SIZE-Y sliders, or decrease the "+ Y# g% E: q U$ h" ]& Z- W
"number of cars by lowering the NUMBER slider.\n"% Z3 w4 o! U4 I
"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 P8 a. P: v) z% {2 o" I9 L! X crt num-cars5 h4 S5 }( i5 o" u2 K* Q
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' n1 Y" p$ F* Z+ S8 d! ?7 R9 C" h setup-cars0 K7 }# r. x! i1 k# Z* K) P) L! W- o( s
set-car-color
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;; give the turtles an initial speed: Q6 z6 F, s$ w* f% w& i1 H
ask turtles [ set-car-speed ]
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& q% L9 `8 p, @* q9 D8 m reset-ticks
4 G4 {9 p" ]8 G$ T6 m' q7 Xend
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;; Initialize the global variables to appropriate values
3 {4 D$ }* p, i' E. _; Xto setup-globals: k* i4 F2 |) Z9 ]( l7 Y0 [
set current-light nobody ;; just for now, since there are no lights yet0 y4 K4 p7 i3 R( S
set phase 0
" Q8 s2 L5 q' `2 }. q set num-cars-stopped 0
( b& b; q( B+ q: {. l4 M set grid-x-inc world-width / grid-size-x: f. a& ]2 d" v( @' k; O( B/ i% j
set grid-y-inc world-height / grid-size-y% [4 b! e6 B! y. n
: Y/ w' i3 k: [* T& K4 L% R8 G8 V ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
& x% I* Q- v0 ?9 l set acceleration 0.099+ E2 ~' h# V# R+ t& O" ~: J+ c) d
end
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2 Q/ c0 R% n# S$ T2 y8 w9 M+ m+ X- b;; Make the patches have appropriate colors, set up the roads and intersections agentsets, h1 `3 y: e' D* O7 m
;; and initialize the traffic lights to one setting/ M5 }4 D' F2 S) |% _& r3 D
to setup-patches
, a# _7 m" c7 G7 m! {8 e) S: ~ ;; initialize the patch-owned variables and color the patches to a base-color
" S& s3 B0 i" k1 }8 D8 g0 q ask patches
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set intersection? false0 D$ U% d* `( @4 M
set auto? false
- L& j+ g0 j4 V" @7 i. w set green-light-up? true
( O7 n/ a2 H! }# n9 ]% J set my-row -1$ w U: R' J+ ^3 W$ q& b5 ^0 q! {
set my-column -1
; ^' w. D; Y6 W# t% Z4 Y set my-phase -14 D8 P% \7 A( K6 s0 p! y
set pcolor brown + 3$ i2 m9 R5 R% G( x$ S( p+ }) M4 O
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( P9 z$ j+ y5 O9 W ;; initialize the global variables that hold patch agentsets0 X. p) O9 x) }& l$ O+ }
set roads patches with
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(floor((pycor + max-pycor) mod grid-y-inc) = 0)] m; B! A# t9 \- [7 Z
set intersections roads with! W9 l$ o2 X- {
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and* D. p1 j7 w9 e" Y, N% ^
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]
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6 e7 I6 u( ~1 ]" |: qend
" j, m2 z8 H7 W# t" [. m其中定义道路的句子,如下所示,是什么意思啊?4 z+ t: c: X' \2 ?6 I" v1 U7 u
set roads patches with5 g- u% _, t4 O( k& o' i; }6 s
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
6 A( p0 R3 F& K; j, ]& g! ^ (floor((pycor + max-pycor) mod grid-y-inc) = 0)]+ Q2 X6 q. b y+ K" U& S9 }
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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