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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。
$ k& b5 a( S3 M5 s- b' y0 _netlogo自带的social science--traffic grid这一例子当中,
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4 F8 C' [+ `( F' D grid-x-inc ;; the amount of patches in between two roads in the x direction
3 z5 U9 F$ I3 Z% e) t9 ] grid-y-inc ;; the amount of patches in between two roads in the y direction% R5 {9 o [7 l2 X$ s
acceleration ;; the constant that controls how much a car speeds up or slows down by if7 w. ?* K# k+ J7 u7 [: S- g( q: u
;; it is to accelerate or decelerate$ ^# {( A y) Z, c- s: R* W& }
phase ;; keeps track of the phase& @, D) z* ?: d- [, ~
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure+ i( E2 ~! w! R! N. g! @& k
current-light ;; the currently selected light, H( V+ U. H, c% D/ w0 B
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;; patch agentsets) g! n, ?9 e; b( y+ z' C2 N A
intersections ;; agentset containing the patches that are intersections
2 j: |+ y8 B4 j$ F$ m roads ;; agentset containing the patches that are roads
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turtles-own
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8 Y9 Y1 E# k: E7 v speed ;; the speed of the turtle2 _4 X9 ]# [9 G) R3 \3 b/ {7 [- k: j
up-car? ;; true if the turtle moves downwards and false if it moves to the right
; f3 A& R l A' k) K d wait-time ;; the amount of time since the last time a turtle has moved
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patches-own% ]- E" L* a" y' a( a
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0 e+ p% I# @" l; E7 a9 K+ A intersection? ;; true if the patch is at the intersection of two roads
6 P* e/ J; z( q) W green-light-up? ;; true if the green light is above the intersection. otherwise, false.
, q- C% }; j, n0 N, I& v ;; false for a non-intersection patches.
) }( M$ J! |, n% c" ]: c7 T! s) R my-row ;; the row of the intersection counting from the upper left corner of the' i; A. n+ j6 u" t l
;; world. -1 for non-intersection patches.
$ v* k: m" c$ z1 \ my-column ;; the column of the intersection counting from the upper left corner of the
$ b3 ~: x. [' Q- |4 q) z* R ;; world. -1 for non-intersection patches.
6 s# c* }, a$ ?' A3 K my-phase ;; the phase for the intersection. -1 for non-intersection patches." Y- j0 _, b+ R7 P
auto? ;; whether or not this intersection will switch automatically.6 p$ F7 T Z6 @& M' o$ A3 E
;; false for non-intersection patches.: t a& P3 H- P3 `# h
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;;;;;;;;;;;;;;;;;;;;;;
# e( T3 T3 {) t8 z& ~;; Setup Procedures ;;
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3 ~* u9 u5 X$ R6 x; A, [;; Initialize the display by giving the global and patch variables initial values.
2 ?. [3 P% _8 J;; Create num-cars of turtles if there are enough road patches for one turtle to9 g- Y! Z& i8 T$ H
;; be created per road patch. Set up the plots.! j' V* P- p7 C0 C% h9 {
to setup& O* q. G5 T- ~8 s0 |$ G8 h2 m
ca
( @( c, w8 w w/ {8 Q3 |0 _6 K setup-globals- F: k5 v4 X2 y& G+ v G$ W, A) {
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;; First we ask the patches to draw themselves and set up a few variables+ [/ F8 r" B* W3 l2 z
setup-patches; I J9 u2 o, k& V& O, ?, Q* W
make-current one-of intersections
3 I+ W0 e, X1 T0 Q label-current& b( F- [5 l' p6 G; { a
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set-default-shape turtles "car": X0 J% L! a/ v# Q
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if (num-cars > count roads), }" L& Z' y! O M! l, ?& \/ N
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' I4 g3 X2 m( h1 I- G, Y' \7 m. X user-message (word "There are too many cars for the amount of "
8 a/ X2 `$ {" ?0 c3 C( D "road. Either increase the amount of roads "
( f4 i, b( J* d' [( Y7 R% o4 ` "by increasing the GRID-SIZE-X or "6 Y- w7 N- _& l
"GRID-SIZE-Y sliders, or decrease the "
0 q( N9 m, n' V5 R0 R "number of cars by lowering the NUMBER slider.\n"
# o+ S# c4 B6 D- [& | `* ` "The setup has stopped.")
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
$ N' F* K% u: c, R' V- y crt num-cars! y/ J+ }* \( U Q/ M# B$ r9 C
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setup-cars
8 y0 T1 G+ k+ a! z* n set-car-color
, U- b- C( d* O record-data8 e5 D q. O" j4 S1 g( p( b# v; K+ E+ {
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;; give the turtles an initial speed
1 o& g0 O, g! J! U# R% X/ n. ]4 u3 N ask turtles [ set-car-speed ]
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reset-ticks, x3 k$ r6 _) l- ^
end
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;; Initialize the global variables to appropriate values$ @/ i- p5 c* l8 H8 p
to setup-globals% X7 M9 @) R. k
set current-light nobody ;; just for now, since there are no lights yet( Q, O. b5 ]- R! a' @9 D* u% a
set phase 0: ?, U2 u, D1 e( Q
set num-cars-stopped 0: j; K$ g1 L& J5 h
set grid-x-inc world-width / grid-size-x
/ G0 f3 }2 U8 H5 o# P set grid-y-inc world-height / grid-size-y
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. K% _* K1 W9 T ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary6 F% Z" f% m3 b F: b1 A
set acceleration 0.099/ E6 m! {7 n1 ]8 U6 G: E) y
end2 m. q, ?2 _6 x( p2 ~4 [
/ \5 H1 t$ q ]% b" d6 L0 A7 p; |;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
0 n7 {# \/ b) L+ a;; and initialize the traffic lights to one setting
2 B2 a' y" `. y, [1 i! ~to setup-patches
3 _3 J, U: T1 H9 G8 G; p/ l" m( N ;; initialize the patch-owned variables and color the patches to a base-color
/ q, _, L3 D i& N ask patches' r( p$ I& A9 V6 W z$ Y8 k1 f
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1 h6 v- _! t7 y: }1 ]1 A N% I set intersection? false8 U' n8 [3 ] H
set auto? false
! i/ _8 ]4 L1 A' _, M2 ~9 N set green-light-up? true
8 L( G5 B0 j- w% {8 X, R+ s% H set my-row -1
3 [8 R1 w O( _& g( { set my-column -1
% C5 Z* V4 I2 L, r, ] p set my-phase -1: }8 }6 Z' ^+ A3 L4 y& Z% M
set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets9 r9 P% r# M4 j, G" x: S' Z
set roads patches with7 q% d$ B4 u" l' [" ^6 n% V
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
/ U+ r. O0 m: Q- a (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
0 [7 W5 E4 O; s% p8 L set intersections roads with
2 m2 M2 W/ {& d+ A [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
8 M/ G$ O. a/ c \+ p1 O (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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7 H/ P& C3 C3 [7 }& e ask roads [ set pcolor white ] n0 z: Q. B8 h4 ]9 b5 o
setup-intersections; X1 Z; D; N6 r
end9 `0 E( p# e* m
其中定义道路的句子,如下所示,是什么意思啊?
+ e$ x: N4 E8 D1 N7 M# O! H( D set roads patches with0 d8 z* T$ R( n% w
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or$ y3 X0 q- e# `+ Y( T
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]+ E( W- ]" L0 \+ }5 i/ d, p5 p
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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