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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。- R s4 H0 G* V/ T; G# E
netlogo自带的social science--traffic grid这一例子当中,
" f& ^" a! ~& g3 b: @" Jglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction3 o( @6 b5 t# [4 W* i
grid-y-inc ;; the amount of patches in between two roads in the y direction
9 e0 @0 V* D: ?. k9 z acceleration ;; the constant that controls how much a car speeds up or slows down by if
% ?+ @4 F& _& M Q ;; it is to accelerate or decelerate- C1 n+ u: \* d: z8 Q! K: m' x
phase ;; keeps track of the phase( d& [0 Y. Z+ x3 _0 n8 O9 U& o
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
7 U# I- O3 N* g6 q* e current-light ;; the currently selected light
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;; patch agentsets3 g0 E7 y: ~# A, I: M0 A
intersections ;; agentset containing the patches that are intersections D: O2 M6 I! a3 e
roads ;; agentset containing the patches that are roads
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4 F" w- B5 s0 m9 g- s _turtles-own
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5 T2 ?, z. f0 m8 \* B! Q0 W speed ;; the speed of the turtle. m$ V2 d; s4 P- M# l5 W
up-car? ;; true if the turtle moves downwards and false if it moves to the right
/ j( z1 J; A6 H. t wait-time ;; the amount of time since the last time a turtle has moved% C: {. O% j' L: W6 O0 E
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3 V7 q- o+ Z `/ Epatches-own3 u0 c" m$ K4 q" t1 ]
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intersection? ;; true if the patch is at the intersection of two roads
' z; d) `+ T# W2 b5 R green-light-up? ;; true if the green light is above the intersection. otherwise, false.
7 e2 `) S q9 V+ I0 [2 c5 L* I ;; false for a non-intersection patches.. x+ k4 X/ ~: B
my-row ;; the row of the intersection counting from the upper left corner of the- ?( m) _) \, D8 W; g' J2 R3 h
;; world. -1 for non-intersection patches.
2 y8 O4 v( F, Q0 T# ^3 \ my-column ;; the column of the intersection counting from the upper left corner of the9 h" w0 w6 }% \
;; world. -1 for non-intersection patches.; l- N c8 H, L8 M/ R5 f1 Y
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
: E: f u1 L* t6 W auto? ;; whether or not this intersection will switch automatically.
K" g. \2 @+ n: F# O4 g% g- j# X# _ ;; false for non-intersection patches.
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1 E7 y0 l8 Q1 O4 F9 R4 B. L;;;;;;;;;;;;;;;;;;;;;;, o/ }+ [+ C! c$ X2 `3 e5 @
;; Setup Procedures ;;
$ f9 @& \' L8 U) I. H( N;;;;;;;;;;;;;;;;;;;;;;7 a. l1 n2 u% h) E! ?
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;; Initialize the display by giving the global and patch variables initial values.; c9 L Y9 u6 M4 S. @- O" O; h
;; Create num-cars of turtles if there are enough road patches for one turtle to
6 Z4 f/ G) W, q;; be created per road patch. Set up the plots.
- h, y6 R7 t6 F- eto setup9 k, F E" A" r; x% B
ca
, y5 l. v# T2 W+ P7 d6 ~+ ^' V setup-globals; T4 `1 K( q: F! [+ g% G& K9 C
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;; First we ask the patches to draw themselves and set up a few variables0 Z$ V1 u6 j: s
setup-patches
! R& T" V) T% |' e" x T, D" r make-current one-of intersections
{& d3 P) Z, b+ c) S) ~ label-current
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set-default-shape turtles "car"5 j0 T/ r* f7 @. U$ B. h
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if (num-cars > count roads)/ h2 Y% T6 C7 R
[
0 X1 L8 |/ ^2 J8 i1 _: ] user-message (word "There are too many cars for the amount of "
& G( y' N. Y1 A/ I) U "road. Either increase the amount of roads "& {5 x' t4 A3 S0 s
"by increasing the GRID-SIZE-X or "
0 |& \( |$ B- P6 M- S "GRID-SIZE-Y sliders, or decrease the "
0 t/ {4 O. y1 r# E* c. q "number of cars by lowering the NUMBER slider.\n"
9 U! J+ P2 K0 \# {4 A) g- B8 ]" p8 T' ` "The setup has stopped.")
( x& t7 ]& x1 d) [: n6 b8 F stop
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* v, K3 x; _; K( O6 l ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
0 Y+ M3 T8 V4 ~& j, \/ j crt num-cars; G8 U4 a3 R( \4 Y+ I9 L- j8 j
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setup-cars
# @$ `% j" f; m. @: K" F set-car-color, u3 C+ w$ y1 s/ g/ O
record-data6 y1 J$ C( x3 t1 {/ _
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;; give the turtles an initial speed5 N9 k5 S6 g, n- ]
ask turtles [ set-car-speed ]
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reset-ticks
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;; Initialize the global variables to appropriate values6 s; b& l# _* s% `
to setup-globals" w. W" q- ^3 p+ R5 x0 r$ a( w
set current-light nobody ;; just for now, since there are no lights yet
3 _% b3 v5 _ c& x$ ]$ E1 ] set phase 0. U) V5 N5 Y, E5 j# R. N
set num-cars-stopped 0
* ?- ?* `! |/ G set grid-x-inc world-width / grid-size-x+ X W$ [& z1 q" u! J5 S* c0 U
set grid-y-inc world-height / grid-size-y3 {+ @, e- u) A, V9 K: _" l$ E
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
2 X" O9 W" W. s$ W set acceleration 0.099# V- S6 g" l, I+ d7 w8 ~
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
6 S+ ^4 C6 w, y' Z+ H( x;; and initialize the traffic lights to one setting O; |( I# T- }" I& m, U+ e( u
to setup-patches( H6 ?+ }. s: C+ s
;; initialize the patch-owned variables and color the patches to a base-color
$ L, e4 r; a" [! u1 X1 J ask patches3 u4 T; e# l0 ^0 W9 m" S- W
[
9 n. c: x% e1 ?0 e! u set intersection? false
6 q% w" F7 D; S, h set auto? false$ M; e9 A+ e' h" {$ k
set green-light-up? true+ h' u- }" H. ~) _, L; J2 ?
set my-row -1' Z3 m% M' o/ ~! X' Y4 h& a/ m, S
set my-column -1
* @! S7 X+ \. b( S6 n8 J set my-phase -1$ Y$ K3 I" \! U; }$ H
set pcolor brown + 3
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$ p2 ?1 O% B* U ;; initialize the global variables that hold patch agentsets( O) H" }- v" y6 z% L* t8 u6 {
set roads patches with
) j# @1 K& h3 s+ x8 A W [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
( ~+ u w* B$ Z6 a (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
- v$ i7 O/ P3 c! o- c* P set intersections roads with! z2 L7 `8 H- L/ s. C
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
! v1 }4 Y; p2 P (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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) {7 |" v" v' h- f: q ask roads [ set pcolor white ]
5 x% l) | ?( z# \+ G: O2 ?' y setup-intersections8 d @1 q! ^9 ?0 s: C
end6 ^9 m( y1 d' ?' w, g) i
其中定义道路的句子,如下所示,是什么意思啊?/ V- `0 u3 d& f2 ^
set roads patches with5 ~. i" m$ _' l. ^
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or. ~! c* Q, }1 K: I
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]3 @# C+ g, n! m. d$ v
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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