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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。+ J/ A. ~7 r6 f5 O9 N) L. }. B
netlogo自带的social science--traffic grid这一例子当中,+ u6 f4 e2 |( i m
globals% n$ a+ t+ \ Z/ K
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& ^& j2 X; c7 S grid-x-inc ;; the amount of patches in between two roads in the x direction$ z% u( d, |0 d' }- j3 d
grid-y-inc ;; the amount of patches in between two roads in the y direction" R" Z% K3 O- P q1 A7 O. e
acceleration ;; the constant that controls how much a car speeds up or slows down by if
/ w' {8 S1 E7 y5 P; v' A+ Q ;; it is to accelerate or decelerate
1 H6 c6 ?8 W0 W5 F phase ;; keeps track of the phase
9 n- S" q+ C' i num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure& B) R3 l# y: W5 Q* N
current-light ;; the currently selected light7 T! S. W- P) l3 u8 Z# W% z
! `8 O+ W2 W: ?5 r' \+ s ;; patch agentsets" {" |, q6 S) n* w5 T' E8 J
intersections ;; agentset containing the patches that are intersections
: R0 C+ k" l2 \1 ^' L& Z/ ? roads ;; agentset containing the patches that are roads
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turtles-own2 B0 m1 x8 s/ S8 b. {# m' ?, `
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speed ;; the speed of the turtle( l$ }2 w0 ~1 J) V/ `) b: G
up-car? ;; true if the turtle moves downwards and false if it moves to the right- Q' f: i0 e9 x; A& M' _$ z
wait-time ;; the amount of time since the last time a turtle has moved7 x/ I4 ?9 n$ M9 O X
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patches-own2 v9 S" `0 H* [% o+ n5 G
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intersection? ;; true if the patch is at the intersection of two roads, G# s/ g3 ~* V5 L. J
green-light-up? ;; true if the green light is above the intersection. otherwise, false.4 q; c; e. Q# T
;; false for a non-intersection patches.
) u# i E5 R6 N R9 X9 \ my-row ;; the row of the intersection counting from the upper left corner of the
3 v' K: `3 R( D) A3 Y, t7 k! w ;; world. -1 for non-intersection patches.- @ k+ x3 ~( C) D& R
my-column ;; the column of the intersection counting from the upper left corner of the
$ g6 B" ^' |. d, q# A/ O* v! ^ ;; world. -1 for non-intersection patches.( n8 Q' d0 s& x3 s$ w9 D; }
my-phase ;; the phase for the intersection. -1 for non-intersection patches.5 i9 V5 y1 ]. k
auto? ;; whether or not this intersection will switch automatically.
* q% D( h" D) Q. `9 X* M$ i+ Z ;; false for non-intersection patches.
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! [8 t7 g! F2 l- z' {6 @7 s;;;;;;;;;;;;;;;;;;;;;;- V. N$ O$ \) x/ U+ D9 u
;; Setup Procedures ;;
: e* p( R7 y |) \: r. h;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.2 @& l3 R k5 |& j) p3 g- }
;; Create num-cars of turtles if there are enough road patches for one turtle to$ X) b& E+ U2 F9 |, n# |! W6 j
;; be created per road patch. Set up the plots.3 v3 x0 B6 Y" M
to setup
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- x8 ^1 f3 { B1 S1 b setup-globals
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;; First we ask the patches to draw themselves and set up a few variables5 E$ N! x2 ]2 a2 M# r
setup-patches7 X5 V$ Y! d- C: j9 ]7 {
make-current one-of intersections' O: ~- o! w- P% V; y
label-current
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% }1 B) E1 q! F- S- O set-default-shape turtles "car"/ f" Z6 H1 J# ]: c8 z, t0 N
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if (num-cars > count roads)! Z" m+ J3 g0 q% T2 U
[
/ `) d7 F( ?# D+ i: J( c& x o user-message (word "There are too many cars for the amount of "
9 U) N' y# ~) M. _- e "road. Either increase the amount of roads "
{/ l8 h- b5 Z. @; C "by increasing the GRID-SIZE-X or "
; q0 P- x6 i& w! e9 M Y) D \' X "GRID-SIZE-Y sliders, or decrease the "7 ~% p6 A! P! \
"number of cars by lowering the NUMBER slider.\n"
" A1 _! R% b$ J "The setup has stopped.")
/ P+ J: U* z* C* R stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color" a: g& ~: d$ T; r6 A3 h
crt num-cars
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setup-cars! X& A# S; |% Q j
set-car-color3 o. l3 y0 n0 k% M/ b0 u8 U
record-data
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; @0 |2 T7 z- S0 q ;; give the turtles an initial speed
* v# R, _! T% d ask turtles [ set-car-speed ]3 c @' C1 |, S" Q0 M0 j
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reset-ticks
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6 f' [$ Z; e* k;; Initialize the global variables to appropriate values! g$ D8 `& H0 M+ i* S
to setup-globals# O" j! X! u; A: Z a1 {
set current-light nobody ;; just for now, since there are no lights yet
& _; S& A; z; m; q6 [6 ^# i set phase 0
# n _% Z! V) ]2 q0 ?/ d set num-cars-stopped 0. N3 b/ |, M7 @9 z
set grid-x-inc world-width / grid-size-x
! O% H T. x& x" s; K' Q" V* x set grid-y-inc world-height / grid-size-y
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. Q% |6 N. G1 X& L ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
& R% X8 I. k* c( w) k set acceleration 0.099- F" |; k$ _) } h6 q: F6 T [
end1 j. g4 c' y3 Q! ]
+ ^6 l& b" V! D8 w9 E% g3 Q" r;; Make the patches have appropriate colors, set up the roads and intersections agentsets,( n& a2 ]- c% j9 j
;; and initialize the traffic lights to one setting
x# }( @3 e+ l. e1 kto setup-patches! G4 D7 R A% T! o+ Y* |9 [
;; initialize the patch-owned variables and color the patches to a base-color4 e$ c! B" n- H2 g5 N. V
ask patches
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5 k! a7 h R$ j( g5 _ set intersection? false+ D( X& R& Q) m& G; i3 b, W
set auto? false8 w9 |) V, I. i" t
set green-light-up? true
$ d( V6 {$ S; ~9 d set my-row -1% P9 o8 P a- s0 k
set my-column -1: O* d0 B% ?1 g5 Q1 k
set my-phase -1
m: i9 K* ~) w# a. a set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets" x, I8 V- X/ c- E
set roads patches with* k0 }, T3 }- }& }# ]" w; I
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
# U. C4 b) ~' n' s2 H (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
/ u% C( W8 j, | R set intersections roads with
- K0 N' i% r7 a+ H3 t( G! G [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
7 j9 `( G/ F, b( T- F (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]' J% d4 [+ T6 y/ m3 h; t
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?8 V, M/ F2 Q" d7 ]7 B& G$ H9 e7 K \
set roads patches with* I4 e9 u, g( `, E/ V0 [+ j
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
& A' G- }/ e; G6 Q (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
! R; C' k3 |0 Q: X- H( e5 C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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