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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。" x3 j5 {: e- a/ L$ X$ H2 K
netlogo自带的social science--traffic grid这一例子当中,# _: [) C' L* J% N3 H; ~4 J3 D) M
globals& B: s& g C/ f( w' E
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grid-x-inc ;; the amount of patches in between two roads in the x direction7 }" |/ s2 U3 Q/ Z; i |+ i
grid-y-inc ;; the amount of patches in between two roads in the y direction
) i. S2 S" ?- k acceleration ;; the constant that controls how much a car speeds up or slows down by if
! l0 E+ o( ~9 w- _ ;; it is to accelerate or decelerate+ M! N' A9 Q5 Z
phase ;; keeps track of the phase
" g3 q2 U6 I( | X num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure# f6 `8 P, Q' x
current-light ;; the currently selected light
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;; patch agentsets A: p8 g. G+ m; }+ C9 |/ y/ e
intersections ;; agentset containing the patches that are intersections
/ f; A! \. D/ p7 m/ z: d roads ;; agentset containing the patches that are roads4 J- U/ f# N: I4 e ^
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turtles-own
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: X5 i# W9 k! U2 d2 y4 U9 I speed ;; the speed of the turtle$ ]+ l! T: I1 {3 t
up-car? ;; true if the turtle moves downwards and false if it moves to the right" D2 p3 v9 }! p6 e4 m+ j
wait-time ;; the amount of time since the last time a turtle has moved
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patches-own$ D9 @( I' n7 R a1 Q# ^- B3 a
[
9 K0 d3 j/ `2 s2 i+ K7 v' H+ P intersection? ;; true if the patch is at the intersection of two roads8 y, x Q: L1 Y7 f7 U# |) N$ V* P
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
5 n" D' N. w: |* T% E ;; false for a non-intersection patches.0 z; U/ \5 H' A: b; C8 t# I- r
my-row ;; the row of the intersection counting from the upper left corner of the
8 ~6 b1 Q( ]) h4 O+ _! G$ X. M8 R ;; world. -1 for non-intersection patches.
( \6 t% J7 F6 X+ ^ my-column ;; the column of the intersection counting from the upper left corner of the
: Q2 g0 \! b2 @ ;; world. -1 for non-intersection patches.
& A$ U+ G0 v( L4 m" N t my-phase ;; the phase for the intersection. -1 for non-intersection patches.
- \; ]" J2 I5 w- ]+ v( u# O auto? ;; whether or not this intersection will switch automatically.: E) G1 Q e% Z7 P0 O6 ~: S9 A
;; false for non-intersection patches.
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: N; b- u* l* u! R;;;;;;;;;;;;;;;;;;;;;;
: j9 Q; @. R$ w* k8 L) z* F;; Setup Procedures ;;( ^, m- K; M1 @$ ~ k
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;; Initialize the display by giving the global and patch variables initial values. ?& Y& X- [" D- T" d
;; Create num-cars of turtles if there are enough road patches for one turtle to
: c; G& v2 c9 m6 Z5 w;; be created per road patch. Set up the plots.
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setup-globals6 ]8 |" V6 q1 \- x
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;; First we ask the patches to draw themselves and set up a few variables; Z1 D4 x( V" _& k! j$ P
setup-patches
1 a; B0 t- _; g' b; a make-current one-of intersections
$ S3 [6 y5 a Z8 C4 `# j label-current
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set-default-shape turtles "car"
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if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "
# [2 d% r z$ _9 |% Z0 Y$ s6 N% v "road. Either increase the amount of roads "( C0 h) X$ j) Q3 q( a$ y
"by increasing the GRID-SIZE-X or "
1 F: a8 ?$ k y2 g/ ~ "GRID-SIZE-Y sliders, or decrease the "- Z+ `: w. B) P$ F& r6 Q! @+ H
"number of cars by lowering the NUMBER slider.\n"; r0 Y. B4 d: t3 B
"The setup has stopped.")* u3 w6 ~0 N( y3 Y
stop
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8 N7 I2 G5 X5 K4 E0 ~6 o/ u( J; N ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color: R! ?1 {' U8 G9 [
crt num-cars
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" B3 J% ^! T6 K9 {! Y% g% | i0 C setup-cars5 x( A" T8 g) q+ z6 N
set-car-color( k) P" f% o! x- [: p
record-data
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- m" O9 X5 v: W3 ?0 F ;; give the turtles an initial speed, G# B% k, h, A A
ask turtles [ set-car-speed ]
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reset-ticks
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. r; |% _! L6 w$ c4 T% F;; Initialize the global variables to appropriate values
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' B3 ^9 Q4 Q. y8 g7 Q set current-light nobody ;; just for now, since there are no lights yet
9 ?) k" u/ L; T set phase 0
( u( x I! x( \ W) ~1 p) B set num-cars-stopped 0
4 Y: v% j5 o. p6 @/ x set grid-x-inc world-width / grid-size-x
) }; M' R! A b7 h' T+ y set grid-y-inc world-height / grid-size-y
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
5 j4 v3 M; P8 D set acceleration 0.099" P& e* {$ p8 u N3 g1 s& C# Y
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
6 P; H2 {7 R( l* z;; and initialize the traffic lights to one setting# G+ t/ L( _0 X/ r1 Z
to setup-patches6 k7 c# R8 s1 J6 i4 U
;; initialize the patch-owned variables and color the patches to a base-color8 W9 x; [* u Q1 ^% G
ask patches
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set intersection? false! R. a# E! Q. W
set auto? false
7 h0 M7 B B5 Y7 d) L. L: q: m9 O set green-light-up? true$ p- ]. R) P! `# L' V' a) c
set my-row -1& `! n% }: |( x) |
set my-column -1
& I9 a, v. n# }+ n2 r5 X! g set my-phase -1# ~! |" `" u6 X! T( ~! n$ c8 g
set pcolor brown + 3
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8 Y* }' @* i0 ^) l0 x ;; initialize the global variables that hold patch agentsets7 l) m: H# M1 {* T- l# D8 o
set roads patches with/ l/ U# j7 ]! g% x7 V5 _5 q
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or/ [8 E* b' H* t( A7 D# l1 P
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 ~2 }) R9 e) J2 E7 L# H2 d set intersections roads with
" H5 M' `. w [- N2 v/ K [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and# @( o9 M4 l! P1 {. J
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]' x1 |2 s5 w0 s7 q
setup-intersections) P; t- z4 c6 R. K5 O
end g, x& s, p9 K* W- v( Q- U# ]- C
其中定义道路的句子,如下所示,是什么意思啊?5 l, I2 O% B( X" \9 U
set roads patches with# G" i& U( M$ ^+ E
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or* h/ C2 E7 Z* V6 O
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]: p# j" @3 R+ h) T( P6 Q
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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