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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。
% u3 k q: D% B' K5 nnetlogo自带的social science--traffic grid这一例子当中," y! u9 ]( A) r2 z) b5 l
globals
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# R0 G2 H- m H' m8 @ grid-x-inc ;; the amount of patches in between two roads in the x direction( {! ]$ G: _ r, g) ]
grid-y-inc ;; the amount of patches in between two roads in the y direction$ E9 B8 V1 i; f& x0 j+ T% Z& a
acceleration ;; the constant that controls how much a car speeds up or slows down by if. @6 `; R4 E/ p) l
;; it is to accelerate or decelerate
, x/ q/ h! ]8 L0 P3 I3 Z phase ;; keeps track of the phase
: N0 p( S4 r& J: T num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
( e2 L8 w0 r- s5 C# | current-light ;; the currently selected light2 {9 x( ] ?+ J/ d* d) Z- s" i/ _9 S
( p9 @* {- _& @, F: Y ;; patch agentsets2 }& I, O+ I, x% _) J! L A: |$ d' P- t
intersections ;; agentset containing the patches that are intersections6 S8 d- p7 u: d+ ^* z
roads ;; agentset containing the patches that are roads6 I; [. c8 x4 E2 `( J: A
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turtles-own) _3 u* v' ^7 ^5 W0 R) z* k# t
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speed ;; the speed of the turtle
4 [0 V' ?* z, M4 q; o, E up-car? ;; true if the turtle moves downwards and false if it moves to the right/ e$ }3 V. K/ `/ C6 \+ t
wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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' a6 `% H2 V8 T* W/ W' {" U( B6 X intersection? ;; true if the patch is at the intersection of two roads2 q* k5 W: G% X; W) r
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
# T) T) Q1 B1 l2 y& I9 ?, V ;; false for a non-intersection patches.9 D/ b2 H; }7 f6 D- C c9 X x9 I
my-row ;; the row of the intersection counting from the upper left corner of the
; b5 F( a, F0 b7 e! l ;; world. -1 for non-intersection patches.
T" q" X4 t) J8 X6 c+ [: ^ my-column ;; the column of the intersection counting from the upper left corner of the; C- x' |6 t- S
;; world. -1 for non-intersection patches.! u3 a; i7 G b/ ]) s
my-phase ;; the phase for the intersection. -1 for non-intersection patches.% }# X, h: g6 a6 y
auto? ;; whether or not this intersection will switch automatically.% C$ I$ j/ x: d& M0 ]/ _
;; false for non-intersection patches.
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7 F' X+ \3 d7 J& ^7 Q. q/ P0 ?;;;;;;;;;;;;;;;;;;;;;;
& J! u% ]3 m- V;; Setup Procedures ;;# R$ M' z+ }; X" s9 o7 K3 J# C
;;;;;;;;;;;;;;;;;;;;;;
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" D' v! Q( z" [! V' ~* [! n;; Initialize the display by giving the global and patch variables initial values.
/ L' f" k& N3 };; Create num-cars of turtles if there are enough road patches for one turtle to& u9 s- N. l; M: O& G& {
;; be created per road patch. Set up the plots.' K6 Y* J2 x k Z
to setup) e5 I9 l0 Y! C5 u
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setup-globals
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;; First we ask the patches to draw themselves and set up a few variables2 u1 ^9 Y+ }( B1 i
setup-patches. G$ q& z% }+ \: Z! d: s( K
make-current one-of intersections% d9 X, V2 ?& Q" |& y5 _0 h
label-current& y& R, `8 o7 n$ ~) i3 K& ~
5 u4 Z9 [5 w4 m- | set-default-shape turtles "car"9 @1 g$ x. [* K0 x% ^; e
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if (num-cars > count roads)
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/ N5 d' f0 H3 T& D/ q# }6 Z user-message (word "There are too many cars for the amount of "# D+ e2 G9 d6 e# I
"road. Either increase the amount of roads "4 \# z" O# Y$ H' h! R, P4 Y3 u
"by increasing the GRID-SIZE-X or "
! P7 z' P5 F4 s/ [8 S# q; X6 _ "GRID-SIZE-Y sliders, or decrease the "
g% `' l# ]' V7 C( U2 L "number of cars by lowering the NUMBER slider.\n"; i5 A4 r$ @4 r% x$ S
"The setup has stopped.")+ b7 B0 T9 d; N6 n0 z+ P) q
stop+ l9 S# D5 F* B }6 L
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color4 H5 w- v' \( ~3 S% A- x
crt num-cars( ^$ y8 J- f6 ?( c; o" K
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set-car-color: U1 A' z; ^0 ]& o, z( j
record-data. G1 A1 J% A5 m* ]3 l- E( C
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;; give the turtles an initial speed! W( M2 n L. k' ]
ask turtles [ set-car-speed ]
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reset-ticks4 v7 v' }8 C1 f! Y
end
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;; Initialize the global variables to appropriate values7 ^) f. N0 c- K U6 w3 f
to setup-globals
% F1 ?6 w" G4 s3 _# I) s set current-light nobody ;; just for now, since there are no lights yet. U% [2 f* T" F" k
set phase 01 Y, z5 a! v) [
set num-cars-stopped 0
4 Q; z( a% ^6 g# {/ @7 G set grid-x-inc world-width / grid-size-x
% M7 h$ g0 Y! g1 w [ set grid-y-inc world-height / grid-size-y
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
) C. V" c" g6 X/ j3 w+ g& ` set acceleration 0.099
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, t1 r0 a3 M F' \2 q+ f% q* q;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
+ w0 `- `9 P% R; H4 V' `& r;; and initialize the traffic lights to one setting6 a! _0 g) j) T5 H0 A8 `
to setup-patches" i, p# q2 x! j- e5 K% k! Z; }# _
;; initialize the patch-owned variables and color the patches to a base-color
8 X/ b/ i( Q1 J8 q+ ~ ask patches
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set intersection? false
: C% V l- X/ x' u( g d set auto? false! K$ T+ q$ {& S0 r
set green-light-up? true
! y* E8 e( n& g, K* p m+ Q1 O* S V2 n set my-row -11 V( |) f. a( r+ j
set my-column -1
' r$ K! {9 L% G9 K4 h5 c; ~ set my-phase -1
/ \6 s) }! M) o: x set pcolor brown + 30 o& t" k. |7 j8 R+ T$ ]3 l9 ^
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;; initialize the global variables that hold patch agentsets
; x$ l* v1 t' [! i: F set roads patches with
9 M3 T" S, P& ^' O; t [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or& m" _% I; z4 {6 { i9 i
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]2 o% G7 g4 p2 Z0 Y' }
set intersections roads with" L' u1 _. y+ T u# ]1 j+ E
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and: A$ M- e. k! b- ~1 M& F
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]6 x9 B$ k3 ]( X9 }- n
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ask roads [ set pcolor white ]
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end; R6 e( u3 L& d8 M
其中定义道路的句子,如下所示,是什么意思啊?7 I; n! }( p$ u
set roads patches with
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(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
% C' Q: ?% }' ]1 u$ R5 L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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