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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。! e! x$ p4 J0 `7 n& D4 G$ j3 x
netlogo自带的social science--traffic grid这一例子当中,/ F; e, W% c6 B. P. f* H
globals
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0 {8 ~5 U5 @4 }! \! P6 ~) T grid-x-inc ;; the amount of patches in between two roads in the x direction
! r& H) Q" S- N8 p! J& P grid-y-inc ;; the amount of patches in between two roads in the y direction
8 ]0 j4 ~0 ]$ }# a& e" l1 J acceleration ;; the constant that controls how much a car speeds up or slows down by if. O0 g+ Z6 z8 X% G2 p1 ~! F6 I# R
;; it is to accelerate or decelerate
" j' k+ }, j4 p# k7 ? phase ;; keeps track of the phase
% g; |. \8 B; p9 w; ^# L+ Z num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
+ H6 |* m) D. W; p) [8 b b current-light ;; the currently selected light2 w! A; s* G5 D$ ^
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;; patch agentsets5 H* s0 S/ B% E% A; j$ ^8 O
intersections ;; agentset containing the patches that are intersections+ {' k& A+ C" n% x% x
roads ;; agentset containing the patches that are roads1 k8 @7 i1 ~9 e0 }0 B
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turtles-own
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speed ;; the speed of the turtle4 f0 M" a% d6 ^3 z% s7 b
up-car? ;; true if the turtle moves downwards and false if it moves to the right4 I ?( Z- @, ^, u% Y
wait-time ;; the amount of time since the last time a turtle has moved
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& Q: p* c4 l4 A4 Ipatches-own
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9 o) T, Z# q, ?1 E intersection? ;; true if the patch is at the intersection of two roads) w( s- j I' o9 B
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
0 c8 X' c3 ^: {2 J ;; false for a non-intersection patches.0 F1 m9 y* C* b! k
my-row ;; the row of the intersection counting from the upper left corner of the
9 N* z, |. a. Q4 e ;; world. -1 for non-intersection patches.# M6 R& t! @# y( r
my-column ;; the column of the intersection counting from the upper left corner of the
2 [" \; o# d6 t! C6 w' ^ ;; world. -1 for non-intersection patches.5 Q1 k9 M# b# Y5 W7 l6 E
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
( j$ Z% C$ d1 P$ i4 s auto? ;; whether or not this intersection will switch automatically.
/ g* Z- g- Z: _5 G/ t& m: j; Z ;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;
4 X4 J) K$ y2 g3 U0 u9 n' B;; Setup Procedures ;;. X6 H2 h' F$ v) f8 C
;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.7 _9 C' b8 ?/ `; C8 s- n
;; Create num-cars of turtles if there are enough road patches for one turtle to0 b6 Z! k0 {4 x: p. v4 B, a
;; be created per road patch. Set up the plots.
o! x! ?* N3 I- X4 Nto setup
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setup-globals
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;; First we ask the patches to draw themselves and set up a few variables
, e: n9 N0 i7 A+ ^( H setup-patches. e. }$ T: u8 G* P$ U% _! v3 `, m
make-current one-of intersections
$ T- e/ g8 X1 |3 F* ?. ?& t label-current
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set-default-shape turtles "car"' @/ j0 B1 I$ x7 }4 ~& N% [3 B" d
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if (num-cars > count roads)6 }; W5 b; s) v6 C) P- `
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user-message (word "There are too many cars for the amount of "
/ r% x6 y' f) P/ D2 ^- y "road. Either increase the amount of roads "
' l# E! v3 ?) h9 P "by increasing the GRID-SIZE-X or "4 r8 W- D3 U" {
"GRID-SIZE-Y sliders, or decrease the "
& t" U3 n$ k/ G' X/ V( k9 K "number of cars by lowering the NUMBER slider.\n"
. S# `% e1 x- `2 t! d "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. [( E2 X) |+ U' @
crt num-cars
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# z( h. o/ x1 s setup-cars
; @! w: s1 c" @ ?! S7 q set-car-color
2 s0 L1 X4 _ D5 J! s, S record-data
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;; give the turtles an initial speed* J+ s: ^( k* t8 t
ask turtles [ set-car-speed ]
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reset-ticks1 h' m, T. H. V6 \
end
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* L: i8 d, F5 y: H$ I+ W) v' b4 l;; Initialize the global variables to appropriate values
1 n7 Q! B) ^& {8 I; Bto setup-globals. ~ G9 d! r- U
set current-light nobody ;; just for now, since there are no lights yet
: E- a# ]( ]8 q" I$ W1 o7 M set phase 02 E; n1 W( z% ]$ n$ @) R, j
set num-cars-stopped 0% z& f* O) X& k+ p& {- L
set grid-x-inc world-width / grid-size-x$ B# b! a8 j% s: \
set grid-y-inc world-height / grid-size-y
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. R. `" b! A; y) u( k9 W/ m q ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary3 F6 ^$ e h, W
set acceleration 0.099- q+ h- C; \/ Q( n
end1 x+ f- ~2 q0 w" e7 [
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,! t0 V( G; `8 Q$ G! v
;; and initialize the traffic lights to one setting( e2 S) J7 ]* u2 [
to setup-patches
- ]- n2 C9 j/ o5 U ;; initialize the patch-owned variables and color the patches to a base-color
3 O O: P4 q# P5 D/ o# D0 D# s ask patches
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set intersection? false/ \9 d7 l1 [" L3 q V' @3 }
set auto? false
6 j, q( X }( M6 H set green-light-up? true
( q9 |% A& m) I$ [ set my-row -1& t* o! J2 w) w* _/ e" o
set my-column -1
1 }) Z5 l# P# C& P; p3 Q0 F4 N9 P* h% b set my-phase -1
2 j2 l* m8 J8 [ set pcolor brown + 3) m7 x+ j2 ]* Z/ [
]
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;; initialize the global variables that hold patch agentsets( }2 B: u1 u5 e+ q4 _5 `9 I0 Q
set roads patches with" F$ _. @/ x' Q- f
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or& D a" x. y) I" Y% h, a5 ~6 D: y4 S
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]5 r h6 G, B1 l* o% O
set intersections roads with. f0 K) Y! u3 j+ @& a
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
: ]& }' Q) ^% @& E" M. B (floor((pycor + max-pycor) mod grid-y-inc) = 0)]7 z! X! A4 @; k% W
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ask roads [ set pcolor white ]( U) h" B- T9 a5 N. L
setup-intersections/ c3 Q/ Y1 v: q2 s. Z7 ^7 L
end# c% g+ }, ?' E0 B
其中定义道路的句子,如下所示,是什么意思啊?
$ @+ G- Y1 ?3 w; H set roads patches with
/ F4 R$ j- u# \- }5 x" O1 w [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
: k6 A2 n( }5 K4 u/ S- x) M (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
8 S& S4 s a e& J9 p; f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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