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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。
2 E8 q# R2 v. y4 E7 Hnetlogo自带的social science--traffic grid这一例子当中,
/ t6 w- [. p% J* v2 Mglobals' i, M2 g' ~- X( r Y' a
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c2 N+ q+ {) T9 } grid-x-inc ;; the amount of patches in between two roads in the x direction
: l& n6 {7 j: ~& y' l) m grid-y-inc ;; the amount of patches in between two roads in the y direction
: g9 p) R& G- t/ ~: j/ a acceleration ;; the constant that controls how much a car speeds up or slows down by if
1 v! c3 @' f; ?: M( _1 t5 F* W ;; it is to accelerate or decelerate
! P+ \) L! W+ a2 ]! C' n phase ;; keeps track of the phase
0 l8 O# I" R- Y f2 ` num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure5 b r! A& o, q& g% ^$ G( l
current-light ;; the currently selected light
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;; patch agentsets' w; e9 W$ M5 B7 S% Q8 ~' c2 l2 I
intersections ;; agentset containing the patches that are intersections
2 M! i. A' Q" c* l6 F roads ;; agentset containing the patches that are roads
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5 V9 f J Z$ S" Q- Jturtles-own, t! z4 }4 g0 y
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/ E$ c7 ]& L* x; O) T1 l3 | speed ;; the speed of the turtle
5 ]. u% t. [/ f5 W6 H0 E' k up-car? ;; true if the turtle moves downwards and false if it moves to the right7 l3 K) b* S3 G' c
wait-time ;; the amount of time since the last time a turtle has moved
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! m) F! |6 U* z. q' Xpatches-own. ^! L1 o' a5 ]" Y' J5 L: ]
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, Q; a: n, K. N2 S intersection? ;; true if the patch is at the intersection of two roads- @: \- Q C! H! @% s7 _) S
green-light-up? ;; true if the green light is above the intersection. otherwise, false.6 U$ F8 r, K' k- w; `) d B5 l
;; false for a non-intersection patches.4 e9 h" p4 @4 r- X
my-row ;; the row of the intersection counting from the upper left corner of the2 Z/ v1 ]* a, z# c
;; world. -1 for non-intersection patches.
- U+ ?. Y0 i: V2 r$ o5 i- T. T my-column ;; the column of the intersection counting from the upper left corner of the
* [ ~1 k% \, w% P. f ;; world. -1 for non-intersection patches.
* r7 t8 w1 w+ {( P1 @" q' D my-phase ;; the phase for the intersection. -1 for non-intersection patches.6 ^# H5 v3 G- h* C1 M1 {/ P/ @, o) W( J
auto? ;; whether or not this intersection will switch automatically.
2 m# j' r* o7 g @ ;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;) P. j4 R; e: O1 Y8 s5 d- _
;; Setup Procedures ;;
A# z+ Q8 x9 f9 _;;;;;;;;;;;;;;;;;;;;;;" N6 i* U0 n" @$ n+ L5 ~' M# @5 |
) v0 f% V- o9 W/ I: Z% P;; Initialize the display by giving the global and patch variables initial values.- O, e a+ ]9 z4 ^
;; Create num-cars of turtles if there are enough road patches for one turtle to
+ H& i2 F/ u5 M7 P! ?* n;; be created per road patch. Set up the plots.
) K q1 ~2 f" {; ]% gto setup; o3 `6 J' [9 {
ca
; R* @7 Y6 Z( P9 Y' { setup-globals
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;; First we ask the patches to draw themselves and set up a few variables
2 ]) n: s+ g9 T" v setup-patches
' \7 |# S" g* g, n make-current one-of intersections
2 u4 }/ Z2 b8 R: V) A1 j1 w label-current
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* T) N7 R L' [+ K) D6 @ set-default-shape turtles "car"
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" f4 f9 F$ X% X6 X! k if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "
1 j% M8 K2 @3 U# O2 ?# P* Z# l "road. Either increase the amount of roads "
/ b" T9 K7 P: t/ w7 g! u& a "by increasing the GRID-SIZE-X or "7 h8 S, [6 z k8 ~* ?
"GRID-SIZE-Y sliders, or decrease the "
+ V4 U& b- I& Q8 t% W( A "number of cars by lowering the NUMBER slider.\n"/ v/ t4 P0 S% S$ t# A+ v; a9 I/ A
"The setup has stopped.")! }& ~+ o2 ?6 H# ~3 q
stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color% p0 B( H7 f* U
crt num-cars5 W& d. ]+ g D- u& p
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8 a# d* Q9 _2 | J4 q1 H+ x setup-cars
# V" B4 a( l; x3 ?: V) h set-car-color
. x0 }1 x/ M c+ P- c$ a/ G. p: z record-data3 o4 c& I( P+ B" w5 g
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;; give the turtles an initial speed
& [6 ~% G2 L+ q9 m2 [8 K ask turtles [ set-car-speed ]
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1 B* c6 `7 l) M& l reset-ticks
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) ]4 V& l5 `: z7 W3 w- `4 h) t7 {4 j;; Initialize the global variables to appropriate values: f' Y* O' e& W5 u1 e9 G0 P
to setup-globals
# @! P- N4 \; M! D set current-light nobody ;; just for now, since there are no lights yet
$ ]/ ~; i0 `% q* Z set phase 0
+ h% s) H" ]- C3 a6 ?* y set num-cars-stopped 04 W* j' f5 E, L. @# f G
set grid-x-inc world-width / grid-size-x
8 g8 H; Z* A' ]' N' } 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# s* h3 g6 x& _& q3 @4 U
set acceleration 0.099; R1 W3 j) Y& ^4 i
end+ B* _) m0 K* U, P
* O( u0 z! P( Z$ x8 S;; Make the patches have appropriate colors, set up the roads and intersections agentsets,% ]* y' L1 M2 l( M
;; and initialize the traffic lights to one setting: \% h; b5 ?' k
to setup-patches# i$ {- m+ m" N& H; v" W+ D
;; initialize the patch-owned variables and color the patches to a base-color0 {2 s; S, O1 ?2 j: }7 _
ask patches; r. _" J% D; W$ F) R* M# Z
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& l" Y5 J# ?9 R! k set intersection? false
* T* J+ a9 w- \ set auto? false. h, G$ @0 b* @5 e: T! O4 X
set green-light-up? true7 Y4 K4 f M0 D. M
set my-row -1
" i1 a5 O' d J& H! o% f. A set my-column -1' V/ z- @6 V1 [ r" M, L
set my-phase -1
$ q# P# B: ~3 }) q7 Z3 r set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets* i$ A3 f; L7 y# e+ n
set roads patches with
, U" F" R( W0 T S. y& o [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
( e, y4 L/ `% P' ?! A" N1 c (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
) t4 X. [' P+ f+ h2 [4 g1 ] set intersections roads with! s; n' T. m7 n }
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
" }2 e8 O& N# v V. a* l (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]
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其中定义道路的句子,如下所示,是什么意思啊?3 @/ f2 R1 s) D
set roads patches with# z1 @4 @7 B7 g% v, X
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or# S. }5 l! [& j! g
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]9 n, l( Z+ a! w" b
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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