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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。! M# E2 b% H' @! P
netlogo自带的social science--traffic grid这一例子当中,
5 V& F3 K; V6 \globals4 P! u% b: N( o7 g
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' U! L7 K. A. i, q8 b* h/ U5 h grid-x-inc ;; the amount of patches in between two roads in the x direction( W3 C( v% c1 ^+ o- a! v: R, \* C8 x
grid-y-inc ;; the amount of patches in between two roads in the y direction" T7 u; W/ z: s2 P
acceleration ;; the constant that controls how much a car speeds up or slows down by if
" P. D H( T. [3 Y5 k ;; it is to accelerate or decelerate
9 `" Y& \1 c' c, e" [1 }, K phase ;; keeps track of the phase( |/ J; P) o8 R% L( n
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
, L o: N% }% Z& d4 D/ a, L current-light ;; the currently selected light+ r2 J% }( {6 K4 y4 Q
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;; patch agentsets& q% R: ~1 H G# f6 v
intersections ;; agentset containing the patches that are intersections
" Y4 c5 z1 Q$ S* u: }: H roads ;; agentset containing the patches that are roads+ o, g( ^, D0 e2 F2 T; C
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! I) s0 s R% a% kturtles-own
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speed ;; the speed of the turtle
$ z0 O& _- G8 C- i up-car? ;; true if the turtle moves downwards and false if it moves to the right) ]) N o' ~7 r# ^. S; e
wait-time ;; the amount of time since the last time a turtle has moved3 t% {, d- b% | E; q- ~ _: R
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7 O& I( u& \! b3 X1 x* g. P7 M: F. Dpatches-own
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; m8 H6 p% N/ Z r. g# c. ? _5 O intersection? ;; true if the patch is at the intersection of two roads6 t% s# S) J2 @- d
green-light-up? ;; true if the green light is above the intersection. otherwise, false.8 L; R9 f7 M% S! N
;; false for a non-intersection patches.
6 q4 L+ R! Q( i7 G% a6 U! U+ J my-row ;; the row of the intersection counting from the upper left corner of the9 |, s* O- F0 {4 Q
;; world. -1 for non-intersection patches.5 |7 D5 J% T- N }9 F
my-column ;; the column of the intersection counting from the upper left corner of the
# m- z/ }1 M+ B ;; world. -1 for non-intersection patches.
8 d. ~6 O" r: }9 n! a2 R$ m0 K n my-phase ;; the phase for the intersection. -1 for non-intersection patches.
1 c# G- M& N. j auto? ;; whether or not this intersection will switch automatically.! D" v! C& k% h' f% Z3 M) \3 w
;; false for non-intersection patches.$ [: G3 p0 p! J% z+ B3 r
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;;;;;;;;;;;;;;;;;;;;;;# Q' {5 F2 I; L6 b( b
;; Setup Procedures ;;/ f5 ^9 H/ w9 [+ j6 P) t
;;;;;;;;;;;;;;;;;;;;;;$ s3 @+ V, |& k2 J
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;; Initialize the display by giving the global and patch variables initial values.
$ ?- I7 x! J L9 ~5 y: `;; Create num-cars of turtles if there are enough road patches for one turtle to
% Z. h9 b' {5 @;; be created per road patch. Set up the plots. P3 G' ~# k. B6 i- e
to setup
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; h5 n7 q" U0 M5 D# D! C( V* G setup-globals
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;; First we ask the patches to draw themselves and set up a few variables9 {4 }) I) h6 g& j8 i, N, V
setup-patches
1 s& a5 x& j9 l5 e make-current one-of intersections( w# O1 t' w, ]; S# O1 w Q
label-current
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set-default-shape turtles "car"
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. Q5 c6 C" S$ S2 z8 ~ if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "+ |/ j9 K/ `. p$ [+ a6 Y
"road. Either increase the amount of roads "
5 I# L8 G u: x. L2 \6 F- s$ m @4 b "by increasing the GRID-SIZE-X or ": m6 e. q6 ]5 n9 r7 ^ }# P
"GRID-SIZE-Y sliders, or decrease the "$ ^- n. H% ` h# A
"number of cars by lowering the NUMBER slider.\n"& C& i5 D# j$ [+ L2 n
"The setup has stopped.")1 }; v3 U' Q( y; O* ?, f# o( S d
stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
+ n5 I/ h" C' { l! Z crt num-cars3 K# K( |, `2 N2 @
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setup-cars& ]0 ~# B) K% u: e0 W
set-car-color
9 R1 F4 |) K$ k T8 a; R4 B0 c7 P/ G record-data
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6 o( w9 j0 U$ @- Z/ E" w$ A# I ;; give the turtles an initial speed1 x3 B6 _1 b- ~8 z2 L& u
ask turtles [ set-car-speed ]' `0 U; T& k5 h& g
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reset-ticks- O3 s6 f0 i& o: z5 q0 t
end7 z$ _ o/ N5 O' C) j! d- D
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;; Initialize the global variables to appropriate values
6 e8 Q- o. \' W9 N0 j0 `" mto setup-globals
9 D: N2 S1 e, i* Q. n6 G7 E set current-light nobody ;; just for now, since there are no lights yet
6 d# T! {: ]/ w( ^- L8 T" H) z! o E set phase 0
# T. }' d u) R# R4 g! E$ Q set num-cars-stopped 00 X" O, f4 k. {+ b) C: B
set grid-x-inc world-width / grid-size-x. {: \3 P* V" V: I( Z
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: c T! |) ~) q: ^/ _
set acceleration 0.099
* ]/ ]" s# a6 v0 M+ w! R' send
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,2 n5 Z/ h% D' z
;; and initialize the traffic lights to one setting% K) r$ g5 D/ ?; M* F/ Q$ P
to setup-patches9 I- D1 p1 s( k' B4 ?, t
;; initialize the patch-owned variables and color the patches to a base-color
- r/ B4 i5 V1 k- V w3 i$ B ask patches8 B$ x3 N; B2 m! N. _ g. F5 e- `& x
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+ h. @6 s% F! ] set intersection? false
( d" U" q& n: v" H& P( b* y# }1 } set auto? false
9 L* U7 K7 ]; j% N, J' t; F set green-light-up? true$ _* ?* s# c9 m6 U
set my-row -1) I' R3 I7 x" m& v) Z) Q
set my-column -1
0 e! h" E/ i! X! j: D0 _9 u, X$ x; H set my-phase -15 X) J! z$ @ W @9 Z
set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets
$ z4 k1 \* Q9 w+ c3 k set roads patches with
% v" W8 B. h5 v; z8 o( h [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
- b* c; y9 D2 O2 w% k4 X (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
: Y' F" f1 p4 z- o3 g1 B8 ^& F9 w set intersections roads with
& u6 }0 Z& |$ | [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and: y; a% g2 d1 b
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]
' P2 |2 R* g4 `% Q% Q) I/ M 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?
+ X& ^" |5 w* F9 Q# f) ?2 O, G set roads patches with( J0 q3 R m9 r' q2 x, y1 e
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or& A' l( F' {) K; Z* i
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]% m/ Q/ b! Q3 G6 d3 P
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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