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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 [+ b( w/ E
netlogo自带的social science--traffic grid这一例子当中,+ ?) e5 `/ w) {6 U T) J& i: ~+ b* Y- ?
globals# u0 C$ i& ?1 k4 m+ J0 d& O
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grid-x-inc ;; the amount of patches in between two roads in the x direction$ C' ~2 o- w. q3 D- K
grid-y-inc ;; the amount of patches in between two roads in the y direction& C9 D; A" ?$ _# R2 K# Y
acceleration ;; the constant that controls how much a car speeds up or slows down by if
, N' [$ p, r* t) x: H/ Y ;; it is to accelerate or decelerate
7 T- y# K! j6 w; B5 w1 Y phase ;; keeps track of the phase5 D+ g. u+ e( X4 W0 K9 V' K6 N6 \6 A
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure& d0 u5 m: |: c( q m# D% b3 y
current-light ;; the currently selected light/ V$ s4 O) r, T5 y, c
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;; patch agentsets
$ M- K! A0 I% c0 O" @- K intersections ;; agentset containing the patches that are intersections
1 y8 ?8 V/ L4 b5 H } roads ;; agentset containing the patches that are roads/ P. T3 `/ Z2 L+ p- R8 u; Q
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' m# N4 S- V" e) P6 T# aturtles-own
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" H) [5 O# c: n- @ speed ;; the speed of the turtle$ ?& D" }1 `* Y5 Q3 V
up-car? ;; true if the turtle moves downwards and false if it moves to the right: _" Z) F8 T4 T0 _% T
wait-time ;; the amount of time since the last time a turtle has moved" u3 a/ R7 T }" }
]
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1 u) t; t9 c3 ^4 a2 g! n$ ^patches-own% m, Q6 o5 ]- g. Y; X
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intersection? ;; true if the patch is at the intersection of two roads2 ^- a) e. Q1 F4 C s: }1 ?8 @
green-light-up? ;; true if the green light is above the intersection. otherwise, false.0 L$ @$ y5 {9 _! s
;; false for a non-intersection patches.6 j0 [5 v1 {8 a5 v* c, f
my-row ;; the row of the intersection counting from the upper left corner of the* @3 {3 J& j( p+ s4 F' t7 `
;; world. -1 for non-intersection patches.- N+ R8 D% d% N g
my-column ;; the column of the intersection counting from the upper left corner of the
" G; x4 f( T' _5 z; y- K; ] ;; world. -1 for non-intersection patches.- w3 P$ V8 Q4 I3 m# R
my-phase ;; the phase for the intersection. -1 for non-intersection patches.3 m+ t) Z& B* i: z) D# _
auto? ;; whether or not this intersection will switch automatically.
1 D9 A" W7 v) d3 ~: J( T2 e ;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;
6 g' n C5 g E( I' }8 {;; Setup Procedures ;;
# K7 ?9 Q" j0 [) \+ c1 p, i;;;;;;;;;;;;;;;;;;;;;;
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2 c: u$ q3 a- N. w# O8 Q;; Initialize the display by giving the global and patch variables initial values.
( P0 Z) a" a w$ d) Q;; Create num-cars of turtles if there are enough road patches for one turtle to
- {# T* z7 i; \. W( A; |;; be created per road patch. Set up the plots.
1 a, m/ c$ M0 W- Oto setup
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setup-globals& W# U7 E% X' [6 o
! H8 X+ \( R: M2 f. f ;; First we ask the patches to draw themselves and set up a few variables( I4 O [+ n* i s' `
setup-patches
3 z, G: Q. h4 K& K1 O make-current one-of intersections
8 t* H5 B3 z) G/ j% E label-current
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8 ^* ]) |" W% L set-default-shape turtles "car"- X2 o. T G, d& q$ ]9 C: y
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if (num-cars > count roads)
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' S5 b3 L I. _: V7 }, h3 _ user-message (word "There are too many cars for the amount of "! W! V1 j! [( v% ~ }
"road. Either increase the amount of roads "7 o3 t/ Q( i$ w6 r2 L8 v, z3 d4 c
"by increasing the GRID-SIZE-X or "
% }. n* ?" L" Y7 g( E, O "GRID-SIZE-Y sliders, or decrease the "
; G- {5 R1 v0 ]( T0 q "number of cars by lowering the NUMBER slider.\n"
+ k/ g( E6 W! e1 O "The setup has stopped.")3 q, R3 F- Q8 ] s. ?
stop8 Z$ b( ^+ x8 M; l% n* R* ^
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color* ^6 ~* g: @2 {0 t' ~, z1 {
crt num-cars
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setup-cars! H( v$ r& {& c/ E. X, r; c. }7 G' g
set-car-color& S( w2 Y a- B6 g7 F$ b1 B- q
record-data
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3 q- Y8 A5 N+ N+ g% t( F9 O# J4 G2 y ;; give the turtles an initial speed
+ g& h: O5 i- b6 _ ask turtles [ set-car-speed ]% R! s3 S/ u6 W$ }% i! l4 k" m
. X$ x) S$ `( C6 y$ ` reset-ticks
, Z% [* j A; p! m! Y, wend
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;; Initialize the global variables to appropriate values( e4 d R; {$ v! {; L* F
to setup-globals) k/ {+ j2 p7 d5 D/ y* c. l6 ~
set current-light nobody ;; just for now, since there are no lights yet$ R4 Z( a% {* e' \
set phase 0
- p; }* p6 C# g8 Y [( W set num-cars-stopped 0
" Y; ?/ a5 U& q/ Y set grid-x-inc world-width / grid-size-x
' t- Z) ~! |/ g) U+ K) F set grid-y-inc world-height / grid-size-y
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# j; ]; \: P1 j. f" p ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
4 |. ?9 b+ z7 ^4 E: U1 C set acceleration 0.099
& P* E5 \3 u6 b7 W- Z+ f$ u; Lend
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,2 o7 @ d+ Z1 V+ m: U: d* M
;; and initialize the traffic lights to one setting9 d+ q& E- w' C+ o- c" K+ L
to setup-patches
r4 K7 u# w% s& U+ K ? ;; initialize the patch-owned variables and color the patches to a base-color6 _7 E0 @, F8 e( A @& i3 g
ask patches
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% Z6 l8 b ~7 t1 g1 @* ^ set intersection? false1 s, l* b6 @4 e" Q1 h1 A
set auto? false% J X- t+ _+ Q0 P: n
set green-light-up? true
( g3 L) l5 e7 q9 q% } set my-row -1
0 @# J2 c9 l! m/ @$ K: N set my-column -1
R0 ]8 B, ~7 }2 r9 t set my-phase -1: R7 M: H) Z, h5 T2 M7 c
set pcolor brown + 31 X1 u" d/ [. D) M. Z' z; x# v
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;; initialize the global variables that hold patch agentsets# z, u% e- j9 C2 ^
set roads patches with
* Y$ m8 h, b! ]0 C; L. Z [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or) W% \9 k: p1 |* W0 b! f. e
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]/ G. M' D. k. g
set intersections roads with
7 \1 d# s, C" I8 ~ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
^$ x9 r, w0 t. n# c (floor((pycor + max-pycor) mod grid-y-inc) = 0)], `8 T% u+ F- b. w. y. n2 n
2 P& ]' i, Y1 j6 p& P# f2 i, s ask roads [ set pcolor white ]
4 ~# Q# T1 j# X5 F1 E; K 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?
7 X, r! ?/ n% n1 Q4 o) S8 E set roads patches with
$ f* Z1 t. p# ~9 \2 V5 Y0 q [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or4 [( l6 ?1 }' |5 s c
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
) @) A: A5 [" P% ?3 J- {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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