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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。
, B8 C+ `! L2 N1 u' }netlogo自带的social science--traffic grid这一例子当中,
6 ~ i1 u: l; `+ G3 z( J" f1 j& g7 Wglobals$ K$ h' X$ ?( d
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grid-x-inc ;; the amount of patches in between two roads in the x direction
F" M& j, P0 y% s4 ] grid-y-inc ;; the amount of patches in between two roads in the y direction
3 p# L: l* v, A acceleration ;; the constant that controls how much a car speeds up or slows down by if( |* m: A) z7 ~' h- K" {
;; it is to accelerate or decelerate
$ K& m. ^9 y) _& A& z6 T phase ;; keeps track of the phase
& {7 t/ J$ A; G8 t9 ^1 N num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
+ `+ b/ O/ y& y7 F9 F+ r# j+ H current-light ;; the currently selected light
& N$ W2 I) \" m& R1 q _
9 i0 k% [! P( A0 X- {/ v& a ;; patch agentsets
* q! \; I; Y% J) `4 O" h. | intersections ;; agentset containing the patches that are intersections$ W% P# y4 F/ ]- l# o
roads ;; agentset containing the patches that are roads
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0 V. q4 {3 V3 H. F; H, w3 Rturtles-own
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+ ^, @; j; a& i( C9 d1 ? speed ;; the speed of the turtle' W1 Y& r# w$ `0 W
up-car? ;; true if the turtle moves downwards and false if it moves to the right' D0 b7 D2 g0 c6 o T
wait-time ;; the amount of time since the last time a turtle has moved
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, u N6 A( W+ x7 s( ?. o, c& p8 S7 Ppatches-own# j( \$ w8 n& G, Q0 B; o
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4 a; c5 f. N1 n! M9 o z) ?! X intersection? ;; true if the patch is at the intersection of two roads
4 B' d" _! N4 y& r3 k8 a# F green-light-up? ;; true if the green light is above the intersection. otherwise, false.
, H }8 O. _8 C1 Q; d. U ;; false for a non-intersection patches.! [" ?" b3 R$ a& Q* \+ H6 m
my-row ;; the row of the intersection counting from the upper left corner of the
4 C4 Z1 C- @( }" M" _5 o1 O( \/ M" h ;; world. -1 for non-intersection patches.
* f8 n2 Z7 W! @* b3 K( P$ z% C my-column ;; the column of the intersection counting from the upper left corner of the( J% C8 a% i/ {. o$ j! m4 X, [
;; world. -1 for non-intersection patches.
; W9 D" j) x$ I( k) U& k0 \ my-phase ;; the phase for the intersection. -1 for non-intersection patches.
4 Z" r* ~- K( ]0 C4 r7 P6 \- B L/ N auto? ;; whether or not this intersection will switch automatically.& r( _# R+ |) }9 y
;; false for non-intersection patches.
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4 d( [$ K) a( G P7 Y& S/ g;;;;;;;;;;;;;;;;;;;;;;( H0 O) M- y' u4 n4 t( P2 Y. Y
;; Setup Procedures ;;3 M+ T0 v v9 [8 b- q
;;;;;;;;;;;;;;;;;;;;;;/ s# t0 ?6 ]5 `" \- n0 L% W
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;; Initialize the display by giving the global and patch variables initial values.
. o6 Q( a" _% Z/ t, L;; Create num-cars of turtles if there are enough road patches for one turtle to& N7 K5 {7 ~6 v
;; be created per road patch. Set up the plots.
5 @& C- X. B/ G2 c' cto setup
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setup-globals- \1 w1 @- y' f5 d9 a
8 s6 Z- k N' s" X% K, X ;; First we ask the patches to draw themselves and set up a few variables
, T0 N0 q! S; V1 o: _3 n$ d setup-patches) ~) L; C* ?- T! Q; {
make-current one-of intersections3 H. ~* v3 r" `& \+ _& f6 s) b
label-current: e8 s* C E, R8 t. Y/ A
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set-default-shape turtles "car"1 G5 E9 C' d; X6 W c* C
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if (num-cars > count roads); x6 Z; I0 {) a' T1 H3 j3 d
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m; V4 R, A! J7 _ X \; c user-message (word "There are too many cars for the amount of "6 a+ A( y) k0 d# Z. a5 R
"road. Either increase the amount of roads "3 \& k. L7 Y" _3 X' S8 [
"by increasing the GRID-SIZE-X or "+ s! w# O( ?5 w! p# r+ s
"GRID-SIZE-Y sliders, or decrease the "
; r ~( q5 O& Q3 O* @2 F "number of cars by lowering the NUMBER slider.\n"
! K5 H3 J' V1 j% [4 ^4 A4 T, ? "The setup has stopped.")
0 Q+ a" h1 {! D6 V) Y" i# e& V stop
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: _& p: U' N" V$ l- Z0 _ ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color7 f' I+ Q5 s7 i a
crt num-cars
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- g! A* z, w, ~" B: s setup-cars% z& e- n- _, z6 ?) `
set-car-color
! f1 s: a3 I6 l+ ~" n0 B6 O2 z record-data# T) K) U0 S2 ?1 [
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;; give the turtles an initial speed
, A* \/ T# e4 H2 A u ask turtles [ set-car-speed ]
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reset-ticks! } f) z. `; T3 G0 ~( R% K1 ?
end+ O8 O+ R+ G6 O
- l: W4 X, h+ e;; Initialize the global variables to appropriate values
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set current-light nobody ;; just for now, since there are no lights yet) R7 b9 P8 {9 @. T3 t7 R% X
set phase 09 k9 Z- E: s) A1 N6 V- d
set num-cars-stopped 0* Q+ n8 N. t4 _ p
set grid-x-inc world-width / grid-size-x
$ Y$ S. n3 J. `; z set grid-y-inc world-height / grid-size-y, A# E" _* U: \- ]# M' i3 G9 Z/ Y
1 Z D& {! a& H# q! i/ X7 r ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary) L/ A+ ~( j; B( s# i( \
set acceleration 0.099* F1 t; ?: Z @8 `
end
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- d0 R1 a) N4 c/ z; C6 C3 N;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
% q3 \9 U6 j7 ~( s- Y;; and initialize the traffic lights to one setting
( l3 S& G' x: o; v9 Rto setup-patches% s, G" { U6 N2 N
;; initialize the patch-owned variables and color the patches to a base-color
' y3 Q* \; t5 ^- r8 I5 p! T- { ask patches
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set intersection? false, w' r9 w& }& h8 M+ ]0 w- C7 l
set auto? false0 E$ f, S' u. y; x! p% E, P' `
set green-light-up? true! M: y, j5 O5 d+ ^- b. H1 H7 f
set my-row -1
6 Q) ~1 ]5 `0 u set my-column -1
6 Y0 | \# t. ^+ u8 [% m set my-phase -14 r! t1 U; V$ i" s' e: o3 E
set pcolor brown + 3/ e/ s+ H9 T1 I4 R' Z7 W
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;; initialize the global variables that hold patch agentsets; o8 r+ o! V U4 o1 a
set roads patches with% j$ C9 L# v8 s2 ^ G i
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or- ]4 B" T: K2 u
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
8 e. E* o3 D' D" P, ^3 v2 S5 X set intersections roads with4 G7 l, ]0 l$ x
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
( x. U& E* c5 j3 ^ (floor((pycor + max-pycor) mod grid-y-inc) = 0)], w, g- C! R! }$ _: a' i$ U6 ~
8 q2 p9 o9 x5 Z1 m ask roads [ set pcolor white ]5 V$ y& B, T. |& K
setup-intersections
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' E! E5 V/ _. D, R+ A其中定义道路的句子,如下所示,是什么意思啊?
/ y5 g- e6 s# S. F) N set roads patches with
# }% t: B5 u8 [' B. |9 ^ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
' x1 e# b5 O* E (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
; Y8 `' g5 D* b) _% @! Z, p) V* |1 H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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