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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。
: Y+ \: ` j: H) J- c& G/ @netlogo自带的social science--traffic grid这一例子当中,5 Q8 `& V5 n* F# R% G% o7 i" q
globals
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grid-x-inc ;; the amount of patches in between two roads in the x direction' i, E# u( ~. R+ i$ A1 p/ t2 K
grid-y-inc ;; the amount of patches in between two roads in the y direction% R& j. P) i6 {1 d! Y: V0 Y' V
acceleration ;; the constant that controls how much a car speeds up or slows down by if3 R( ~: P; l) u, ?+ }
;; it is to accelerate or decelerate
) F r7 ]' {- G( Q& X5 ^2 i phase ;; keeps track of the phase8 E, @: n1 g8 _, P0 A* t0 Z
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure; g C. s+ j9 L
current-light ;; the currently selected light0 f& O% A1 F1 L! E& f7 r
+ }! J' p/ l$ [8 n ;; patch agentsets9 z6 X/ Q$ w6 R! P, V4 O, ^$ z
intersections ;; agentset containing the patches that are intersections# a- G; I) `6 r- Y! D; O
roads ;; agentset containing the patches that are roads% t3 k& M5 N$ ?( B
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turtles-own. X& u; V1 i2 | I
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speed ;; the speed of the turtle
4 f9 C, R4 V2 k* h0 |# {, w up-car? ;; true if the turtle moves downwards and false if it moves to the right
" c t& B( E* f* E; [ wait-time ;; the amount of time since the last time a turtle has moved' S3 [) C3 U# O4 F
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+ W5 ]' U0 [. ?8 D; w) epatches-own9 }. p6 e5 a+ Z* t5 y, {+ g& L# f @4 i
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intersection? ;; true if the patch is at the intersection of two roads
' X5 S3 @+ s' x) \* A/ E green-light-up? ;; true if the green light is above the intersection. otherwise, false. j9 X- O$ ]- s( Y0 b
;; false for a non-intersection patches.( A! T. O" g, t* ?; z- d
my-row ;; the row of the intersection counting from the upper left corner of the
& V6 W0 G# X _5 ~6 x) s8 g: V ;; world. -1 for non-intersection patches.! [$ h/ C3 E) D' E
my-column ;; the column of the intersection counting from the upper left corner of the$ Q7 L+ j) h! U% y6 p2 x: B
;; world. -1 for non-intersection patches.
+ m/ f/ ~8 Q5 P my-phase ;; the phase for the intersection. -1 for non-intersection patches.
6 g8 ]* J& ?& p) ?. |/ t3 B* X( r auto? ;; whether or not this intersection will switch automatically.4 @9 H" w& D4 O) g$ K5 M
;; false for non-intersection patches.2 H1 U: l+ f" A# k: A4 H9 Q: Y$ t
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; ^& Y3 w* |- n+ i+ ~;;;;;;;;;;;;;;;;;;;;;;
( l! x- g! ?! O! c;; Setup Procedures ;;9 a5 ]% J" y3 `. h: U
;;;;;;;;;;;;;;;;;;;;;;) }% D) g9 P$ m3 u: R4 L& O( K* A' A& Y" g
+ |% ?( d* U* F' j$ t;; Initialize the display by giving the global and patch variables initial values.+ |( _+ d* a7 h" M# D- p5 ~% O
;; Create num-cars of turtles if there are enough road patches for one turtle to
0 r6 G1 A, N9 ^0 Y/ `) O2 B! @;; be created per road patch. Set up the plots.4 E! k; _& g# q1 e
to setup- Z& _) {5 R- Q, \
ca
4 {0 F9 |* [8 M' { setup-globals
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9 s" ]: g* \& B. B/ M+ R1 L ;; First we ask the patches to draw themselves and set up a few variables
6 [2 k# s# `# U7 h+ r setup-patches
5 z* G: I% R9 N8 w6 V& `% J4 h; u& N make-current one-of intersections# p" |& s4 b) z
label-current
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5 W+ y' ?6 b* f' k3 Z3 r k) } set-default-shape turtles "car" |, l2 j' X9 L: y+ \' \7 g" C
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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 "* H$ V+ R. {9 B: m9 o5 ]( G$ [4 W* u5 ~2 ?
"road. Either increase the amount of roads ") I1 o$ ^, c/ h0 C1 V3 ]+ e
"by increasing the GRID-SIZE-X or "
# F2 g! w9 H$ t4 A "GRID-SIZE-Y sliders, or decrease the "
2 @! V( M+ }! J2 T. ~( d; o" L "number of cars by lowering the NUMBER slider.\n"$ y( y) m1 k! a# D, W/ `0 V& f
"The setup has stopped.")! X! a" X# V. j
stop
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- ?& s a* g/ q$ e1 d ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color/ B b, ~3 e( } s$ d9 Z+ p' u
crt num-cars
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setup-cars. x7 a3 ^3 j" }0 C, `# J1 i
set-car-color- H* }# ]- n# C% e: V
record-data }7 U3 h' P6 w1 c- ?% S; \. _* ]' i( S
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;; give the turtles an initial speed
( O: e( e6 C4 o0 h; z4 X ask turtles [ set-car-speed ], J- c" L( D# V4 |* N4 u% ^$ u/ \' v; |
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reset-ticks6 ?1 l2 t/ V0 |( `) ~5 y/ b
end4 Z6 \6 g# `# u$ F
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;; Initialize the global variables to appropriate values
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4 ^# u) ]" a7 A set current-light nobody ;; just for now, since there are no lights yet* w+ |1 y6 K9 s
set phase 0
9 g) a5 \: s; b set num-cars-stopped 0
, q7 Y- z' l8 V- C! f set grid-x-inc world-width / grid-size-x6 o- I0 S7 U! n9 e u
set grid-y-inc world-height / grid-size-y d# T1 Y* {/ R/ {
" G+ X- }8 L1 q: W K ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary3 Q9 p3 E# z' O2 O
set acceleration 0.099. f5 [) C) l A" {4 d
end
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* ?9 D& s8 {' ?! |) j( J, |;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
' J3 ~4 s9 b \$ I$ }3 \;; and initialize the traffic lights to one setting/ w( X0 _. k8 i$ |, v3 B
to setup-patches
j, `$ V4 ^3 A; D: U" \1 J" q ;; initialize the patch-owned variables and color the patches to a base-color
4 V9 j, G9 L, J3 r. T: K! O% l ask patches9 m7 X0 s6 J) i; R7 K
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set intersection? false% ^% d5 u- v8 c4 F( K7 T1 d) n3 Y
set auto? false8 F) f8 I% S! q7 k8 |' b) R: g# z
set green-light-up? true
S5 z& J+ m3 p+ @4 V0 r set my-row -1' I$ c/ m6 m2 Z8 A: `
set my-column -1
0 L9 b% V( u3 K set my-phase -16 V2 j- E$ R! p, Q) e' b
set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets6 C/ t. d1 Q4 N! a! [
set roads patches with T4 [4 }# p1 S- X
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or% C! R6 S& J; U' U
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]' l" E0 M( @1 I4 e
set intersections roads with
: I x/ T2 P3 U [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and# c* q) ~4 M5 }
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]* O* a4 D# d; ^+ _( \
3 E! z) J( A) y4 S ask roads [ set pcolor white ]! ? _1 j: V* ^+ i: o2 @, \: O
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?5 P3 e# t1 E+ p; D9 }
set roads patches with
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(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
& T/ ]' E0 e" O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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