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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。; P! y3 `, Z% ^* e+ k }
netlogo自带的social science--traffic grid这一例子当中,
L* _+ ?8 E' U e1 b5 ^5 Yglobals; V/ i; w: ]6 _
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- B) h+ [; L% y( M# p6 j: P9 y grid-x-inc ;; the amount of patches in between two roads in the x direction
# D6 H, p. I9 G! w/ Y) q grid-y-inc ;; the amount of patches in between two roads in the y direction/ @5 _, S9 n7 K
acceleration ;; the constant that controls how much a car speeds up or slows down by if
; L) R* h, y) t9 ^+ B8 b ;; it is to accelerate or decelerate( m3 n6 \$ X+ k! i0 k
phase ;; keeps track of the phase! [1 u) B2 c8 h. U8 I! m: d. P+ m
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure# C4 }9 W/ g, E- b
current-light ;; the currently selected light
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s8 c, ?: [ u& I5 C5 d ;; patch agentsets' Z& l) \- P5 H& l9 i; o' S- F
intersections ;; agentset containing the patches that are intersections
' m3 p. k/ B% B7 P2 j roads ;; agentset containing the patches that are roads
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turtles-own
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speed ;; the speed of the turtle
. y, H8 n2 m3 m, _ up-car? ;; true if the turtle moves downwards and false if it moves to the right0 k( Y# x# z; `
wait-time ;; the amount of time since the last time a turtle has moved
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6 q6 O$ `) D4 I; N1 K6 \' a3 I$ b: u% A* ^patches-own
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6 Q8 m# w& V4 k/ P; U& |6 U0 u- M \ intersection? ;; true if the patch is at the intersection of two roads/ c2 d; X- u6 h, ?! C* Y; W
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
! q3 K/ @, ]+ j/ X! Q ;; false for a non-intersection patches.( n. o1 ^6 h1 T9 r0 ^( k$ g
my-row ;; the row of the intersection counting from the upper left corner of the' m5 T9 U6 G' V T& G) w
;; world. -1 for non-intersection patches.1 S0 c2 z8 a- ~, i4 \2 p4 T
my-column ;; the column of the intersection counting from the upper left corner of the+ q: k! m. ~7 Y0 u5 N
;; world. -1 for non-intersection patches.( F" \4 Q4 d4 q3 ]1 s+ h6 V _
my-phase ;; the phase for the intersection. -1 for non-intersection patches.* _5 j6 r1 I8 W
auto? ;; whether or not this intersection will switch automatically.
1 @ x3 q! T4 D g, t+ W' W) v5 | ;; false for non-intersection patches.
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5 k) X. m2 s$ C) R) X( {5 @;;;;;;;;;;;;;;;;;;;;;;2 M0 j" f' R4 T
;; Setup Procedures ;;
( k5 h- W& X& w, u7 O5 C8 G;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.
7 I0 {% e& C2 c, w. E2 w$ P;; Create num-cars of turtles if there are enough road patches for one turtle to! z% B I A2 Y: H
;; be created per road patch. Set up the plots.
. G; `: \: w& @7 d: s, Ato setup0 \! X5 k& w5 i) [/ t
ca
3 U" r% w+ L! a: b8 ~$ H# d* X setup-globals
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;; First we ask the patches to draw themselves and set up a few variables
4 S2 ~0 _0 @' B" N7 K4 g" p! ` setup-patches W3 Q/ J7 k& R4 A/ P F$ L' }
make-current one-of intersections
. ^0 g4 @ ?/ L0 f I# C label-current* u9 C d# D* w% Q
1 a( C$ D& K# G' M+ M$ k$ x set-default-shape turtles "car"
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if (num-cars > count roads)4 u6 L( {( S# n
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user-message (word "There are too many cars for the amount of "0 Z4 A5 ] Y4 {( {$ h5 q+ n7 X. E
"road. Either increase the amount of roads "% t, K9 A5 [$ k. X Q& e
"by increasing the GRID-SIZE-X or "& o- V+ T- r4 ]/ R: U4 K+ N
"GRID-SIZE-Y sliders, or decrease the "
, _0 x/ m4 {2 ?( w, C% W+ j "number of cars by lowering the NUMBER slider.\n"
( }* h1 N* u0 F2 R/ J8 [# ]# X5 R "The setup has stopped.")0 w& ~; G2 a( T3 X6 P+ N. e
stop
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5 z! d, q. h- Y- I ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
5 B6 h6 r" m3 i/ ? crt num-cars
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setup-cars# B8 `% a( S. l7 {! |7 n/ R" d0 T
set-car-color
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* W! v7 I* y! G5 y2 H! X& R ;; give the turtles an initial speed3 N) S; U' a/ z2 Q( s2 h
ask turtles [ set-car-speed ]
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" b: A- Z. P) D reset-ticks
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+ y' @, U% z6 v1 P3 O/ k;; Initialize the global variables to appropriate values' s' v2 m+ Y1 {/ v) D& s
to setup-globals
: }( p8 e5 i! `) |7 {3 z set current-light nobody ;; just for now, since there are no lights yet$ S. x3 f0 ?0 D, i! A2 B
set phase 0, W% r& i6 }' U/ e
set num-cars-stopped 0
4 o3 l: @2 ], a/ F/ J D! P. o set grid-x-inc world-width / grid-size-x
: _8 H" O5 s6 ]- n0 A set grid-y-inc world-height / grid-size-y
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- I& n( f" A2 ^& a1 j) q ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
* |& g) C/ a, F4 U- t) S set acceleration 0.099, V8 d, v- N& v+ j
end8 E4 E2 m5 Y) m$ s7 w
: o+ W9 U$ m- V6 V6 l# n;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
% B! O( j# ?( ^% A9 w0 A;; and initialize the traffic lights to one setting/ k( X0 X- `5 ]" _4 k
to setup-patches6 D4 h, X+ n4 a3 A* ^( K, {
;; initialize the patch-owned variables and color the patches to a base-color
: v9 S! g% [. O* U6 { ask patches. k; s% [9 f j9 \ u
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set intersection? false
( n' |* o% ~: E8 F: w+ `! v set auto? false
( L2 |7 U7 ^+ ^1 o set green-light-up? true
) f1 C. `: r1 o0 y set my-row -1$ B! B5 q* `4 q3 g
set my-column -1- G" ?2 o/ s6 N3 P E0 v5 |+ w6 }
set my-phase -1
2 N. o2 n! \! O) Y( k& L set pcolor brown + 3* k1 l% ?& Q G0 k3 T, ]
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;; initialize the global variables that hold patch agentsets
3 h- O. a j+ _. I. j& [4 Z: H set roads patches with
7 x) n+ E9 G: P$ a1 q5 P% b) [- h [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or- G4 H: s7 E8 G7 w) t- k
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
6 a6 v+ l: a' ^9 _2 y8 P# d set intersections roads with
6 A: x0 ?4 F2 }9 q0 M C, F [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
1 p# T8 Q5 E1 M% z) N- u (floor((pycor + max-pycor) mod grid-y-inc) = 0)]4 M9 ]- a0 p* [7 l1 |( W* K" f
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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?
% _6 _( U& E# A: I) O# O set roads patches with6 R8 @8 n, |2 [
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or4 m( h0 k, \- l
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
?) F9 ?- t, I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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