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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。" H# i" k* M& s) Q1 R
netlogo自带的social science--traffic grid这一例子当中,5 {! @6 Q \0 `! S6 V1 U9 n
globals
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) p6 G4 y7 l E grid-x-inc ;; the amount of patches in between two roads in the x direction2 {0 l( D4 f* Q) Q" a. S# X% G* i& N
grid-y-inc ;; the amount of patches in between two roads in the y direction E/ [* e( u% D) |' W4 F7 _0 h
acceleration ;; the constant that controls how much a car speeds up or slows down by if* O# [9 ^+ I4 c, A5 h5 I& r& _
;; it is to accelerate or decelerate
1 T" E2 x, N) m: D) C1 s1 ? phase ;; keeps track of the phase0 c9 V' B( v; F" L6 H V. B& T
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure7 N B3 \: z. W; l) V% |4 T# o) f
current-light ;; the currently selected light
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1 J( J7 S! l; r8 V6 q& n ;; patch agentsets
6 `2 Q T4 t: f( |+ U$ G intersections ;; agentset containing the patches that are intersections
9 a1 W+ l7 R Q7 V# n2 b5 A3 y: j roads ;; agentset containing the patches that are roads' u# d( J4 Z5 t* R P! E3 d3 y* h
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, u1 C# y. v& `4 C* ~/ b" oturtles-own Z5 r1 u. O/ p8 n
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1 ^8 p! K6 _2 F) q( P/ B speed ;; the speed of the turtle
, H; k3 `, |- d) p; e+ M up-car? ;; true if the turtle moves downwards and false if it moves to the right
' I' T! s/ G) ?) N# L4 G4 I wait-time ;; the amount of time since the last time a turtle has moved
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- A4 B/ ?' p5 W* h7 C+ ^! v8 |patches-own, C& L: [/ n0 p1 u2 u# F- q6 y
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intersection? ;; true if the patch is at the intersection of two roads
7 G/ ?' K6 s; Y2 O8 N green-light-up? ;; true if the green light is above the intersection. otherwise, false.! p' j5 o1 c* B& p
;; false for a non-intersection patches./ v9 O) n" |% o
my-row ;; the row of the intersection counting from the upper left corner of the& O6 @' @* \ e, Y
;; world. -1 for non-intersection patches.
* y- T/ d! K0 m: k# r1 j' B my-column ;; the column of the intersection counting from the upper left corner of the; J5 T3 @+ }0 ~; U% w. Z( s
;; world. -1 for non-intersection patches.
A2 u+ B/ l8 b- f) C my-phase ;; the phase for the intersection. -1 for non-intersection patches.
1 j6 m" b2 x4 u, D- e4 d auto? ;; whether or not this intersection will switch automatically.
8 ?( L% f0 ~, z; u ;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;/ _6 N) w) Z% q! I3 c
;; Setup Procedures ;;
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;; Initialize the display by giving the global and patch variables initial values., s) d$ F" F! Z1 t' V& d. ]+ ?
;; Create num-cars of turtles if there are enough road patches for one turtle to
7 |9 o0 n7 H0 c;; be created per road patch. Set up the plots.
$ U: c6 C8 H' k% i- i0 x s7 @5 Zto setup
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& q* c+ d# n, f$ } setup-globals
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. b Q% \* j! U, c, `/ f3 R0 Z ;; First we ask the patches to draw themselves and set up a few variables
, d* c9 l( O) G1 R0 Z% T$ v0 \ setup-patches' F9 i; O/ P- W1 @% O. ?
make-current one-of intersections
/ s/ o3 [5 L6 r; d6 i1 |+ p$ ~ label-current
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set-default-shape turtles "car"+ L0 k4 }/ r/ `# D! [! p
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if (num-cars > count roads) u, f$ u# Q" \' u4 N
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user-message (word "There are too many cars for the amount of "# l) |5 @* C. |- }
"road. Either increase the amount of roads "$ ~7 ]+ ~0 H+ O' k7 r- D8 o
"by increasing the GRID-SIZE-X or "
/ ]' }3 o1 l1 E4 k- l( P "GRID-SIZE-Y sliders, or decrease the ". X. q5 n. b7 D$ g3 i
"number of cars by lowering the NUMBER slider.\n"
q% C3 @: J. m4 j: n5 F1 p+ a. f "The setup has stopped.")
6 x/ u1 P& q7 x2 R! v stop, k, S. d( m6 D. N( y, ~5 R7 j" }
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color2 \- ]7 i4 A5 [( y, V( [8 \7 ~
crt num-cars1 f! a; s: C* a* `% K% i( P% l
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+ f% X: T1 k$ ?8 U E" K setup-cars
0 s3 ~$ J3 H2 [6 ^/ N* k4 L set-car-color
4 T0 k% Y' T) K6 a0 g record-data
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9 d0 y$ h$ C5 W; R; L0 Z ;; give the turtles an initial speed
/ b' X8 R. d8 ]' \4 d* z ask turtles [ set-car-speed ]
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reset-ticks
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4 {" s- ?5 e1 r& a1 Y O4 \;; Initialize the global variables to appropriate values$ E# @1 K" }. N* I! F& Q
to setup-globals. a2 B" _0 d h. z$ r
set current-light nobody ;; just for now, since there are no lights yet8 R' j% q' ~: _- T2 T; Z$ a7 @
set phase 0
& {2 M% N- M4 a/ C; H( X set num-cars-stopped 0
6 u# j, f7 y% [ l( \4 d set grid-x-inc world-width / grid-size-x( ^6 ^5 c! f2 o: {" L2 M7 x
set grid-y-inc world-height / grid-size-y
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5 m! ]9 o; I; l! B' n ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
" O- J# c% y8 F) G0 E) E set acceleration 0.099- h: J/ {. y& E
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
9 V3 C$ s( \, y8 i% z6 s& [;; and initialize the traffic lights to one setting
; A' n* b( {2 ito setup-patches; ]8 A& @8 e/ \% C; g* m7 u
;; initialize the patch-owned variables and color the patches to a base-color
+ u5 S# K- k. S9 W* B; I* g U9 g ask patches
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+ }# r4 I( c9 k7 @ set intersection? false5 A5 g- a. P# z
set auto? false
5 e1 g) F1 Z; n @1 J set green-light-up? true% R: D' _! K0 c. M( S$ l2 q" J& M% D
set my-row -15 ~9 d1 b/ f! O/ C6 y# s
set my-column -1
& O+ C$ L/ B8 e' T6 C% _ set my-phase -1
5 j( `8 I1 v' S9 M" I" I set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets
4 g' ~# W& i$ s9 ~ set roads patches with/ T! v f" c t0 R1 o. {; k, q
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or) _/ p( d, }- G& X$ ]+ }0 M# e
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
3 O5 U. t& F) W' s5 G# f' p set intersections roads with
( E ^/ O" p6 b0 }3 U# N5 W, _ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
0 {8 G7 `* b1 r; F (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]' W4 w, C C3 W G" J( E& E
setup-intersections) x# L2 }* o9 M0 Q' [$ l
end" p$ K' g4 j0 U
其中定义道路的句子,如下所示,是什么意思啊?( n, s, r+ ^9 A
set roads patches with
! @( q K" I2 G8 y1 m# K0 Q9 w4 F5 a0 A [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
* s0 d: K$ f5 J (floor((pycor + max-pycor) mod grid-y-inc) = 0)]& ~9 r; j$ ]. ]& T
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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