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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。2 o" |6 M0 _ x" q) B/ h3 W
netlogo自带的social science--traffic grid这一例子当中,
. _$ J+ _# V0 W) c: X1 \% B5 Mglobals6 ~" g% @$ L X7 Y
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grid-x-inc ;; the amount of patches in between two roads in the x direction
$ e! I' i/ R; B7 z, `( \3 L grid-y-inc ;; the amount of patches in between two roads in the y direction
! v6 Y! G0 T# L8 E" f1 t/ D1 K. D acceleration ;; the constant that controls how much a car speeds up or slows down by if
0 F g6 y, G- b p) v; ^ ;; it is to accelerate or decelerate6 m; i$ a6 \6 s8 {2 H d' |
phase ;; keeps track of the phase
2 |$ N& X. y7 m. p5 z# L+ |" ` num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure1 V, h8 g9 r# O# ~# ~5 [ `) V
current-light ;; the currently selected light3 r; I b Z% n6 f/ |
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;; patch agentsets
4 ~2 V& ?3 u; ]; W intersections ;; agentset containing the patches that are intersections
: B; ]: T! d* n5 Q3 C+ k! w% _& |0 A roads ;; agentset containing the patches that are roads
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7 f3 y& ]& W1 ]turtles-own
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speed ;; the speed of the turtle
/ ^: L; {7 d& U) H( w9 k* B m up-car? ;; true if the turtle moves downwards and false if it moves to the right
, `) e( I" h0 [/ ?! s2 t wait-time ;; the amount of time since the last time a turtle has moved; j1 C3 l+ S3 h+ Z
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! q) x% e9 c4 n8 U1 L1 ~; upatches-own5 u4 Z2 Z c# c Y) H" y7 y
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intersection? ;; true if the patch is at the intersection of two roads
2 j( }7 I( k/ e green-light-up? ;; true if the green light is above the intersection. otherwise, false.( _3 r7 k2 }; T5 Q
;; false for a non-intersection patches." s. _( \" r7 M- n( I! U& \
my-row ;; the row of the intersection counting from the upper left corner of the
% e6 \' Z+ L m4 q& M" u. F ;; world. -1 for non-intersection patches.
* E& _& ?. p1 E: h( W6 r& A my-column ;; the column of the intersection counting from the upper left corner of the
3 E8 g, y' x: h! J3 Y ;; world. -1 for non-intersection patches.* F& C3 w! h, l) W' D
my-phase ;; the phase for the intersection. -1 for non-intersection patches.' }0 H6 T9 A: B, h+ O9 K9 j2 f& J. r
auto? ;; whether or not this intersection will switch automatically.# b1 q& D* w2 p( W' E* C
;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;
6 z0 x9 }1 V, w) t' O! W0 N;; Setup Procedures ;;
& S* Q% g3 k5 d! m& v, V;;;;;;;;;;;;;;;;;;;;;;/ ~* Q1 t+ V: k( X4 C- I
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;; Initialize the display by giving the global and patch variables initial values.1 b6 a/ [- j' g( v
;; Create num-cars of turtles if there are enough road patches for one turtle to
% y; W- e7 \* T7 I; F;; be created per road patch. Set up the plots.
/ ^& l- }8 j! ]% K2 L2 H4 g) A& rto setup! a. j' F: r b1 c5 e0 z6 j
ca
* J; q- [* _$ ~ setup-globals+ p z! P( o8 x, `1 R9 |, n W
4 z6 p" y0 W' P ;; First we ask the patches to draw themselves and set up a few variables4 U' S3 E6 L8 s M: s* R" _
setup-patches$ O( C8 V/ s* a! m3 @+ m i
make-current one-of intersections5 P- N; y- ~# T& b$ ^
label-current
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set-default-shape turtles "car"
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( x/ g3 V( M! G# p2 I if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "
8 ^- A+ L: P/ T# X. y0 v "road. Either increase the amount of roads "
, \6 J) _" W# ~9 n* B v "by increasing the GRID-SIZE-X or "
7 Q: Y' F! t% J( D# k0 v3 Q- h "GRID-SIZE-Y sliders, or decrease the "9 i- c* i; M1 u8 A; p2 N8 z
"number of cars by lowering the NUMBER slider.\n"6 L( `* @. w* q% x# 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
3 D/ b' |! Q0 t% \# t1 O/ e4 T crt num-cars/ r( |* K U$ X9 F$ f
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, R" Z8 ?: L3 [ setup-cars
3 L& Z5 @1 X* s- D+ [ set-car-color
Z3 ` P9 s1 l. U8 ?; }! G6 D record-data# J2 k& X# {, k7 Z
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;; give the turtles an initial speed
9 G' {6 B, L7 j" P' c9 [ v ask turtles [ set-car-speed ]
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* F3 ?1 u5 h S reset-ticks
4 y. Q: G/ l1 j: w3 jend
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;; Initialize the global variables to appropriate values
" ?6 _) C* Y7 Q p$ D9 ~; V; j9 fto setup-globals7 M0 b: l8 y' E' P' X
set current-light nobody ;; just for now, since there are no lights yet
9 U7 ?% d9 M2 q3 } A set phase 0
0 U n% Y. f9 |' h set num-cars-stopped 06 n' c! Y* ?8 n) |# D0 W
set grid-x-inc world-width / grid-size-x
" U& q- T1 `% k! K, d6 @' ] W) x set grid-y-inc world-height / grid-size-y1 ]- E3 L* T, U/ k3 y5 C+ c
# D0 x0 h! `: M# ~( v' F4 D- Q ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary6 V: ^9 i: R8 G# ?
set acceleration 0.0995 t9 C! t8 \6 I8 @: M( ^ ~) s
end' I+ y8 z. l4 }& }
4 [) ]' G0 x8 M' T;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
0 n/ W& ?" Y+ R+ L& {;; and initialize the traffic lights to one setting, I* h6 _& M( m9 d7 H; M5 G
to setup-patches1 h T) K n8 l( e
;; initialize the patch-owned variables and color the patches to a base-color
9 O. ?3 B+ C/ J* M ask patches) V& J" Z( g A# H; ~6 q9 I
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set intersection? false) }9 A+ Y) |; F/ m' N- b
set auto? false
+ }8 n0 A0 H7 W. m% y set green-light-up? true$ K# [8 V ?: i: t
set my-row -1% a6 y1 p# o$ {' x
set my-column -1
2 k- U/ ?* o2 ~ set my-phase -1" b& V+ C; U O) p
set pcolor brown + 3+ |6 U/ d! a. I# b9 M0 t* u
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) ^# `- v2 N$ ?. t* ~1 u+ K; u$ K: u ;; initialize the global variables that hold patch agentsets) U" X: N6 a8 K5 j! ^: G
set roads patches with
1 K) q1 ^+ x% g- I& c( Z5 T$ |' O6 ~ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
- v5 j5 C' A4 e3 T S (floor((pycor + max-pycor) mod grid-y-inc) = 0)]. F; }- w+ q. C2 n. S' L# d
set intersections roads with% v; y- ^- |& V+ h
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and" C" z' k* ~) T8 ^
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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' F; y9 W& ]- w' p ask roads [ set pcolor white ]
% T) S- c G0 Y+ {% m/ {9 c setup-intersections
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其中定义道路的句子,如下所示,是什么意思啊?! m* g0 F5 J. v7 X4 _0 l
set roads patches with
+ _ ?+ }. @' I( K8 | [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or6 I6 A' t" n: L7 N8 M4 p
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
/ K# t2 O8 V' E3 N* v' V0 C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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