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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。, O; O8 Q9 L4 Y4 f& m5 ?5 n& ]5 U' Y
netlogo自带的social science--traffic grid这一例子当中,; g0 I, Y. [4 ~3 N, c) o
globals9 w* A, T5 f! W! H
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4 Y5 P9 }+ C V" S) N grid-x-inc ;; the amount of patches in between two roads in the x direction+ I2 Q4 _5 f- Y3 o! m8 Q
grid-y-inc ;; the amount of patches in between two roads in the y direction8 v& Y/ {6 b: U4 G8 }5 R$ u1 s
acceleration ;; the constant that controls how much a car speeds up or slows down by if
0 J+ |+ S/ i( Q& Q, j- p$ T ;; it is to accelerate or decelerate
) j' _* _. {4 c. T4 } v6 {+ a phase ;; keeps track of the phase
3 p0 d0 o$ T. r" D A& ~ num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure, K( t4 i1 P! ~
current-light ;; the currently selected light
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;; patch agentsets
. c9 X- t8 m+ K& z intersections ;; agentset containing the patches that are intersections
! w9 t$ A: n+ l. o4 K" \- M: x roads ;; agentset containing the patches that are roads+ ~4 _" f! e+ H: ?! }; Y& ~
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turtles-own
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speed ;; the speed of the turtle
* x1 r7 n7 ]8 H) Q4 w- ^ up-car? ;; true if the turtle moves downwards and false if it moves to the right
- N! N$ R$ N6 t5 f wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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0 W) s1 [. ]% @) e$ m intersection? ;; true if the patch is at the intersection of two roads
. i$ l+ `2 ?; I- v green-light-up? ;; true if the green light is above the intersection. otherwise, false.
# g/ x5 p* \% f0 U0 y ;; false for a non-intersection patches.
' ^& q! g4 L6 W( K/ D my-row ;; the row of the intersection counting from the upper left corner of the
2 k' m2 \6 G6 i ;; world. -1 for non-intersection patches.0 k" s: c, m9 G8 R: l9 x
my-column ;; the column of the intersection counting from the upper left corner of the/ P( T; q0 A) c' l. W- Q8 b
;; world. -1 for non-intersection patches.
+ Q; A1 y$ p0 C" J& X# Z! E% m- R' a my-phase ;; the phase for the intersection. -1 for non-intersection patches.6 h# c9 V* Z' ^3 Z' _
auto? ;; whether or not this intersection will switch automatically.
+ }# z9 O* `0 \9 P/ S/ i5 i ;; false for non-intersection patches.
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/ @1 \2 B7 T! y% V5 m;;;;;;;;;;;;;;;;;;;;;;
3 J; q2 g/ [+ Q4 @5 x5 |;; Setup Procedures ;;7 _9 f1 w( p) ]" ]8 M: n C4 G/ I
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;; Initialize the display by giving the global and patch variables initial values.
) k, f: c' f% L' n3 e9 c/ M;; Create num-cars of turtles if there are enough road patches for one turtle to+ g( v8 U, g3 V
;; be created per road patch. Set up the plots.
8 V @# l6 U. H; [ z3 Vto setup: T- _; X I/ D! N
ca
7 h: V2 U# ~8 ?; z setup-globals' Q& k* ^& j0 {- j
2 ^6 q: t2 [. B0 _0 I ;; First we ask the patches to draw themselves and set up a few variables
0 c2 h8 t; }; c+ l setup-patches3 O; W) Z- N2 c
make-current one-of intersections
: H+ {0 o2 b0 ~# [) B" d# I label-current! C* |# g6 R- P a2 u* h
1 e. I8 r0 O# L4 n+ `4 J5 T2 z- q set-default-shape turtles "car"' q, n7 t- ^9 C9 n
$ _2 Q$ w/ q- ]2 o& w- g if (num-cars > count roads)
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$ G5 J; W t6 t- p user-message (word "There are too many cars for the amount of "+ f+ y/ q$ D# p* t) S6 K5 @
"road. Either increase the amount of roads "4 V/ E. C9 f% Y( }3 e; |
"by increasing the GRID-SIZE-X or "
. S/ l' u1 {& |5 W0 J) {8 } "GRID-SIZE-Y sliders, or decrease the "& X( p9 t" Q4 w& ^1 T% G
"number of cars by lowering the NUMBER slider.\n"
/ g; t# I; @- u9 {2 l9 w "The setup has stopped.")
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4 u0 F. \6 N$ x. l: K- e' Q ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
, {% ^3 u( b# Z3 j, }. s& i crt num-cars
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p; ]/ `0 n6 t setup-cars( p2 {5 j$ S% \1 m2 E- z: @
set-car-color+ x/ s5 D2 t4 s
record-data
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;; give the turtles an initial speed
- X# l3 [" B8 @; x' v* X ask turtles [ set-car-speed ]
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reset-ticks
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9 q$ x0 u# B1 ~& ^" u5 Q;; Initialize the global variables to appropriate values
1 ]0 f4 S S7 `6 G9 Q# T$ k1 rto setup-globals
+ t7 `, D, K! c; L e set current-light nobody ;; just for now, since there are no lights yet- S6 V; v; i( b( A) m% \
set phase 0' {/ b! I G V ^9 g
set num-cars-stopped 00 P- @% ?" Q( y% w! F( o$ B9 c3 }
set grid-x-inc world-width / grid-size-x
! k x8 n" P: }; n set grid-y-inc world-height / grid-size-y1 L6 A% C! u; r
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
* `2 L# F; k# E! u$ z- I/ V1 \ set acceleration 0.099
+ P7 X3 e$ v2 G# Eend
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,: k2 t- U) R, O" J+ Q u
;; and initialize the traffic lights to one setting$ v7 n$ K5 A9 ^' ^: D, c
to setup-patches
$ G$ ^ O# v8 R7 j ;; initialize the patch-owned variables and color the patches to a base-color4 c4 w8 I: c) C
ask patches
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set intersection? false
7 G( @" A$ T& M set auto? false. X4 ^* Q3 x i
set green-light-up? true7 O+ o) F/ v% D
set my-row -1
3 C* ?' [8 W2 \5 N ?& F set my-column -1
+ `0 Q ~' Z$ T2 [ set my-phase -1
7 u+ `9 r- |3 Y" A set pcolor brown + 34 Y i5 A S$ X
]
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;; initialize the global variables that hold patch agentsets3 h. _. m+ d# R- }2 F; f7 k
set roads patches with
( Q+ }7 r) q. i( Y. W* z [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
. }3 J6 {5 F; z$ a+ C6 P (floor((pycor + max-pycor) mod grid-y-inc) = 0)]0 B: A* y" s$ `3 v% f
set intersections roads with
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(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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. `, n' Y2 K; R+ W1 y6 @ ask roads [ set pcolor white ]: G F$ ~, g- w* n/ p) r+ Z, g
setup-intersections
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其中定义道路的句子,如下所示,是什么意思啊?
0 _) L" c; |7 B- \ set roads patches with
* D8 s/ H; G$ H2 s [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or" {. G6 B9 d9 r6 K
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
- _% x# Q! @- H$ x# R. 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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