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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。& w' N: X% f- \1 _% A/ i- i
netlogo自带的social science--traffic grid这一例子当中,$ l% {# D5 r( K- L3 z
globals
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grid-x-inc ;; the amount of patches in between two roads in the x direction& w" z; T3 ]% l: u+ Z9 ^
grid-y-inc ;; the amount of patches in between two roads in the y direction
5 r9 _) {# \1 b* M& S. J acceleration ;; the constant that controls how much a car speeds up or slows down by if2 `" K4 E2 h8 z
;; it is to accelerate or decelerate4 ?: \. B( |; f5 S- c5 |9 a
phase ;; keeps track of the phase- I8 v2 H8 K+ a) e! O$ M1 S$ n' v: E/ f
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
% m+ [$ n- |( {% v0 f. p. x current-light ;; the currently selected light
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;; patch agentsets: ^, Y7 d! b2 l3 t' F
intersections ;; agentset containing the patches that are intersections
2 [" x" {1 l7 ?' A: @% c! \' F roads ;; agentset containing the patches that are roads
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" s" M& b+ ^% rturtles-own: _: S) @+ j" W
[
3 V6 `% L' C1 U0 E, b/ a* c% K speed ;; the speed of the turtle
. V H; K9 @' |4 O& V, J+ D4 M5 m up-car? ;; true if the turtle moves downwards and false if it moves to the right
, G1 ^3 |4 p% y8 q$ } w wait-time ;; the amount of time since the last time a turtle has moved
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6 R; ~ ~- o4 T7 J6 r0 q0 `! H* ?patches-own7 Z. \1 m6 U! \( m* [: }' V
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intersection? ;; true if the patch is at the intersection of two roads' r& j5 x, e1 n7 W% L
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
) R+ G8 [6 N- M& }9 C7 B ;; false for a non-intersection patches.3 l2 n: V1 M' X- |% O+ }
my-row ;; the row of the intersection counting from the upper left corner of the
& I$ w! p% s3 V% N; { ;; world. -1 for non-intersection patches.% o* H( M& G% l3 R
my-column ;; the column of the intersection counting from the upper left corner of the
) x7 m+ L# J* r ;; world. -1 for non-intersection patches.
$ }$ H+ o6 f9 E% E+ V# J2 h: [/ i7 ` my-phase ;; the phase for the intersection. -1 for non-intersection patches.
% o) B( s! z2 c5 } auto? ;; whether or not this intersection will switch automatically.
2 {$ x8 F& M# b8 S0 }2 z. U ;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;: I) z3 ^# \$ D5 G
;; Setup Procedures ;;
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, w) s8 d5 z+ o+ Q( l' c' R;; Initialize the display by giving the global and patch variables initial values.
# j t. K# j, s# e% L$ N- x. d;; Create num-cars of turtles if there are enough road patches for one turtle to1 R/ B& K6 z& r. c
;; be created per road patch. Set up the plots.3 O3 t# E6 A# _% x
to setup
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& k1 n3 ]# {' \% h7 ^ setup-globals- F+ j; D+ f* ~& O' g& l5 F
0 Z' {3 ^$ p: p& [# p: B ;; First we ask the patches to draw themselves and set up a few variables1 b% O8 [* B' t
setup-patches8 M; y! \7 Q7 X8 ~6 u. X8 z T
make-current one-of intersections
% V* L! T& A+ {& W label-current
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set-default-shape turtles "car"& w; k$ n( Y4 J% K
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if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "
8 i: u; F2 p. @! L4 | "road. Either increase the amount of roads "' W T8 W9 J* P: Z
"by increasing the GRID-SIZE-X or "
2 d s, u: u8 b! U0 o6 [7 I "GRID-SIZE-Y sliders, or decrease the "
; P% g% R! u* i5 Q "number of cars by lowering the NUMBER slider.\n"3 Z, V' { g' x X0 C
"The setup has stopped.")7 k! K8 }5 p2 M0 h' {
stop! X1 K, a# b; F
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
1 C8 Z! l- J6 @ crt num-cars/ l: ~" e7 N+ R/ u1 D
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setup-cars
6 d: `6 F. C2 p7 {; V$ O9 O set-car-color
& q7 [* Y: W- J5 W/ H record-data( P- d/ J) s( K6 ^5 m# H( H W, X* i3 Z
]
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- P( [+ x' ]- ~ ;; give the turtles an initial speed
2 W+ z) @' l8 f$ a. k ask turtles [ set-car-speed ]
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reset-ticks
* J) M* Y9 L9 i# bend
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# R7 F- o# K8 G$ Z% E. h: p. Y;; Initialize the global variables to appropriate values" ?6 |6 v) B2 n% V6 `( E" C
to setup-globals
8 I* r/ g7 l# J5 h% p set current-light nobody ;; just for now, since there are no lights yet* e# X# C7 {; y5 J; c. h
set phase 0
! [8 S4 k9 Y+ a9 f set num-cars-stopped 0
$ g3 \+ e5 Y# E3 ?5 ~" x set grid-x-inc world-width / grid-size-x
! b4 x5 ]) s/ u3 u0 A' \ set grid-y-inc world-height / grid-size-y/ P& W7 Y$ ?# M, j! C
8 M! ?; W9 P+ K, Z ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary+ s" K: z+ I9 Q& R
set acceleration 0.0995 A- t+ X# s0 o
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
" p2 q: |7 I4 \. D/ _9 T. x0 @;; and initialize the traffic lights to one setting# c, ^* ]$ T5 |, c
to setup-patches! {6 S8 W% x- z l: b0 X: v
;; initialize the patch-owned variables and color the patches to a base-color
! B9 \2 h5 |; M0 s ask patches2 o* h2 k i0 j2 A! [( d( w) ~; J; H
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set intersection? false
; L8 ^4 m/ p0 | set auto? false
: i) F5 g3 w% s6 y set green-light-up? true' O9 |8 z' P; i
set my-row -1, m4 v l. i* h/ N& Q
set my-column -1
o4 q) P" L0 i* c3 Q! p3 e set my-phase -14 t; e* k) K. m) G' u
set pcolor brown + 3' ~8 ~9 r! ~( U, _6 ^0 \
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;; initialize the global variables that hold patch agentsets- s5 n ?: X! D$ H
set roads patches with
6 t- e0 p; \# l9 E/ O+ N [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
& t" S$ }( ]0 x; y/ R) r. V) I, I7 G (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
! K/ e1 j( \2 s set intersections roads with/ _1 _) W; Y2 e: H) r
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and: p1 z0 b# `3 i! u$ z
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]
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end) D/ m1 u: i3 M3 g8 G% M1 |: s9 [
其中定义道路的句子,如下所示,是什么意思啊?
8 n- U! K( ?7 x$ ?. N: ?/ x n set roads patches with" ]' W6 E* j: Y8 G6 d
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
) E8 S- d( R3 V, {0 G (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 A3 e0 j: C8 n) 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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