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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。# K7 [& s5 H8 M+ g
netlogo自带的social science--traffic grid这一例子当中,
! Z0 s% w$ y8 N4 y5 M% y' U$ uglobals4 @* i+ ] o% q' I8 x" I* |
[
8 l- t& R8 c3 Z3 x6 G grid-x-inc ;; the amount of patches in between two roads in the x direction
% W! [: h, D9 k grid-y-inc ;; the amount of patches in between two roads in the y direction
9 g! G. N/ d3 S: w6 S9 R acceleration ;; the constant that controls how much a car speeds up or slows down by if, y% k3 f R1 \2 t
;; it is to accelerate or decelerate
& T- I7 ~3 ?5 d' b2 W5 K4 ` phase ;; keeps track of the phase
- @. ~7 M5 i5 j0 [; q num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
; E6 c, W5 F z* k) [: F current-light ;; the currently selected light
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;; patch agentsets
1 k; L3 U3 R1 Z" ^* J1 [ intersections ;; agentset containing the patches that are intersections
6 G) ]# q$ [: g( E9 Y( `, e6 g roads ;; agentset containing the patches that are roads! y2 A6 @, K- D1 p* m) j1 C
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turtles-own
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. g; j/ Y* m3 g9 u4 |7 E" {( Q. p speed ;; the speed of the turtle7 e1 l$ u/ a" u8 t1 s% |8 m/ F
up-car? ;; true if the turtle moves downwards and false if it moves to the right
, O9 K4 L4 j5 m wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads4 s$ v0 ]4 D2 _8 @. [' R7 x# F- c
green-light-up? ;; true if the green light is above the intersection. otherwise, false.$ s; H* f5 i; x/ R9 b
;; false for a non-intersection patches.
( P6 [1 }1 o! G9 r/ J* u' j my-row ;; the row of the intersection counting from the upper left corner of the
* }! u# x/ m8 j ;; world. -1 for non-intersection patches.
( D" [& c7 Y# J" S7 ]4 t" l/ C+ T my-column ;; the column of the intersection counting from the upper left corner of the# S2 d+ D- i2 ?4 B
;; world. -1 for non-intersection patches.
" ]# X1 _5 ]' E my-phase ;; the phase for the intersection. -1 for non-intersection patches.
- G3 {2 T; a8 q7 s( Y; { auto? ;; whether or not this intersection will switch automatically.( l9 U! m0 K& n% D
;; false for non-intersection patches.: f+ ]$ V- r1 W3 T( c
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;;;;;;;;;;;;;;;;;;;;;;
6 B7 r+ t/ C" }- f8 T# n. t;; Setup Procedures ;;+ ^" t4 I7 Y; t- T& L8 P4 Y
;;;;;;;;;;;;;;;;;;;;;;7 s, n& r: V, |# Z {1 o
, W. A- {! x* X. M ];; Initialize the display by giving the global and patch variables initial values.
0 c% d& y5 R* _; G;; Create num-cars of turtles if there are enough road patches for one turtle to
0 \" M4 k: U1 R+ }4 U;; be created per road patch. Set up the plots.+ J4 T" d- j. v+ O& \1 N
to setup3 ^! I. N5 `5 G4 H: h! d6 [. l
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setup-globals4 M6 t$ K0 |/ `& I- |
0 a; l" l7 Z1 B) h2 v% z3 y ;; First we ask the patches to draw themselves and set up a few variables' O/ L" z& u! w2 T* K
setup-patches
& Q3 q% X3 n6 A' D& x make-current one-of intersections
% f& D" X/ X3 A; Z1 c2 I label-current
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3 ]& G! `! R! f4 y Z set-default-shape turtles "car"
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' Y, I1 f/ b3 H8 U4 n$ O' p- X if (num-cars > count roads)
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& U# O) L+ a- j! @) P user-message (word "There are too many cars for the amount of "
' G+ R7 S% e! Y "road. Either increase the amount of roads "
$ p% W, i5 r0 p7 c: } "by increasing the GRID-SIZE-X or "
( w# ^. Z8 L1 k1 b "GRID-SIZE-Y sliders, or decrease the "/ @# ~, s) o+ q7 b% u. W
"number of cars by lowering the NUMBER slider.\n") z# ^- t% Y2 F( c7 `- \3 G/ [
"The setup has stopped.")8 b2 Z4 D2 t8 e# [; f
stop3 [# f3 e3 i7 y' b4 D; m- t
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* F( S4 R: g( L- } ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color1 \6 p8 M5 ]6 S: L* L
crt num-cars
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setup-cars: W7 c1 i% S0 m$ @# c0 e1 \
set-car-color& H* \) R% @( a, u9 M4 ^1 \) ~' R
record-data2 B% X) K& B+ F7 d
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1 ]7 V& g$ b, U. y6 } ;; give the turtles an initial speed" ]4 @* E+ F: X g7 G8 x; A4 l
ask turtles [ set-car-speed ]
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reset-ticks
4 u. Q0 f3 W% `; U0 send. t" n5 X; v* ^
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;; Initialize the global variables to appropriate values
# V6 S% N9 e" B/ D6 k- Lto setup-globals3 q* r" A( N/ f0 a' D: }
set current-light nobody ;; just for now, since there are no lights yet
( K2 \8 d B3 c2 U set phase 08 _7 C. e5 f4 K; i* o
set num-cars-stopped 0. [- a1 E# ^$ A3 o' r" z
set grid-x-inc world-width / grid-size-x' ^; O6 h1 }! k# e* l( y% @ R3 b
set grid-y-inc world-height / grid-size-y6 S# l$ q$ J- H. m4 e' A" L# @6 p
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
: f& A% O7 F- N' s4 Y/ d set acceleration 0.099
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) H' q! S0 w; a! I6 n;; Make the patches have appropriate colors, set up the roads and intersections agentsets,7 E/ D4 g& r+ U+ x' ~
;; and initialize the traffic lights to one setting
% \- a* p4 G6 K( H1 j/ y u* vto setup-patches
- D9 P+ v7 ^* @ ?" l& j ;; initialize the patch-owned variables and color the patches to a base-color2 t3 @& A. b' {% v2 H
ask patches
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. }: Q# s: i {2 g* R4 b set intersection? false
2 @* e; C8 K, s' Q( A set auto? false! y: z( h7 N! ~+ @9 L/ N
set green-light-up? true& E$ G6 G3 x3 `' R' Q! j9 f- s) T
set my-row -1
- {) k7 Y/ d* X. L3 O set my-column -1
r' @9 N% `8 ]1 t& S. D set my-phase -1
9 p: i# } z7 C% d7 ]5 B0 b% v9 X set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets) p4 M- R% ~" ~ h7 X
set roads patches with) K: ~$ f! S4 i) V) s' I
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or& u2 q, }$ L6 _; M" h4 g$ Q
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]/ j- g; p+ t- t: X6 k2 o
set intersections roads with% q( h% ?: ?- |3 N
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
$ d6 n+ y, e P9 T0 V+ ~! n/ Q (floor((pycor + max-pycor) mod grid-y-inc) = 0)], A" V( M5 i: m# J! t) v/ @
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ask roads [ set pcolor white ]
6 F- r. ], q# r+ Q. g setup-intersections
: [$ F0 i: O9 k- q- S. V; Jend
E2 [! Q3 v5 H其中定义道路的句子,如下所示,是什么意思啊?
6 r" o' Q6 x& L# G5 E( G set roads patches with
B: S0 I6 K( C' ?3 Z2 L5 S8 A! j! z [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or3 y$ k! x/ x4 ^
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
6 U: {0 H3 l ]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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