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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。0 `. y9 K- D1 K* u
netlogo自带的social science--traffic grid这一例子当中,
& ]$ O6 C# j; I6 t- Xglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction3 u' _2 ?/ p9 C2 q9 T5 Z
grid-y-inc ;; the amount of patches in between two roads in the y direction$ r2 D( h6 r' \3 M
acceleration ;; the constant that controls how much a car speeds up or slows down by if1 p4 f& j6 h q: _& n" ~
;; it is to accelerate or decelerate" A7 s; I7 v( {8 ?+ W. h. [
phase ;; keeps track of the phase9 x* c5 t r% f' e9 g
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
: E" q* \4 Z0 { current-light ;; the currently selected light
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;; patch agentsets
: f4 h& t% L' Y# y+ L$ b8 J intersections ;; agentset containing the patches that are intersections
2 G8 A2 w% [" Q) _; G I( o roads ;; agentset containing the patches that are roads
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turtles-own+ _. f, s4 [1 u" M( ~( M6 c
[
5 E9 Z0 P1 |; G! c speed ;; the speed of the turtle1 ^' a2 H: `1 X! D6 n) d; c( Y
up-car? ;; true if the turtle moves downwards and false if it moves to the right6 w: {5 V4 W3 m# F( [+ l
wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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3 g1 b" k; c: {) E6 R; [ intersection? ;; true if the patch is at the intersection of two roads
8 J. o1 j7 n; `+ k green-light-up? ;; true if the green light is above the intersection. otherwise, false.4 E+ u; l! Z [3 N! Q
;; false for a non-intersection patches.
! X) w$ L& D/ N" _9 t: d my-row ;; the row of the intersection counting from the upper left corner of the# X# [/ g. q& ?! f+ a
;; world. -1 for non-intersection patches./ s9 f1 V9 y: N/ q9 {$ R
my-column ;; the column of the intersection counting from the upper left corner of the$ H' t5 s0 _1 Q' Q
;; world. -1 for non-intersection patches.- y$ M- D! M4 k1 G- M5 b* p8 [
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
% E$ Y# c8 }* K5 y& W auto? ;; whether or not this intersection will switch automatically.3 V8 t# b( V0 h3 x/ `' d5 ~
;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;
* i4 V J# B8 s5 R% `;; Setup Procedures ;;
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;; Initialize the display by giving the global and patch variables initial values.. V: F0 B# {8 Z( N* \
;; Create num-cars of turtles if there are enough road patches for one turtle to3 F3 Z Y2 n; f' _# k& I9 @2 M
;; be created per road patch. Set up the plots.
( i$ n$ y+ m9 `% v. L! kto setup
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setup-globals
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5 G/ W+ D( P! i% v+ f$ ], d ;; First we ask the patches to draw themselves and set up a few variables
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make-current one-of intersections
; S: J' b! ~1 {4 f) P* r! C% _ label-current; ]$ p6 Y( _8 r
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set-default-shape turtles "car"* ]/ V5 ^8 w' t" U8 M
* T- i0 T0 a6 [0 O) v$ _) _ if (num-cars > count roads)- { G5 ?5 ]& f4 [$ S8 A$ Z
[
% o5 b2 x) G7 l) c; E; M$ w user-message (word "There are too many cars for the amount of "
$ i" k/ P0 k- v, U8 K. W* ` "road. Either increase the amount of roads ": @7 t% n p! u$ {
"by increasing the GRID-SIZE-X or "
. S3 q8 J4 B8 U( r2 w8 \ "GRID-SIZE-Y sliders, or decrease the "
% s B, }+ J1 c& Y+ k5 X. f "number of cars by lowering the NUMBER slider.\n"
; N2 G" z" U% w2 N8 \2 U; k "The setup has stopped.")) X* K; E; Q; z ^ i1 T5 V8 g
stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color( P+ T% U7 S! V% A9 j& K, H
crt num-cars
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* M9 H3 i% a0 f, l* X setup-cars
2 N/ P1 E% y5 n set-car-color5 M7 n* ^9 @" o+ _
record-data
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;; give the turtles an initial speed
h8 N& u y B6 Z u2 m4 E ask turtles [ set-car-speed ]0 K! h8 S' p- B4 ~" l
: M( ^0 H: E. n4 g7 J/ U8 d reset-ticks
0 y; P$ x! L! E# Fend
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# T! I4 H( N. m( k;; Initialize the global variables to appropriate values
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' F# a* `3 _ `% T set current-light nobody ;; just for now, since there are no lights yet
7 c. W) S% `$ T0 e$ F$ I0 H- | set phase 0, ^8 C4 B+ b+ i3 K7 _: {) \
set num-cars-stopped 0
4 U. c0 L6 V! x8 C. f, R6 v1 c set grid-x-inc world-width / grid-size-x j5 H$ J& d$ n. i \
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 boundary3 i, x& s/ C2 R, a; k
set acceleration 0.099
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
# w4 [( M9 f% f7 Y |;; and initialize the traffic lights to one setting) s6 D" z1 H9 N+ w, N% T, d0 f1 y
to setup-patches9 q/ X9 c$ J4 j& [0 W
;; initialize the patch-owned variables and color the patches to a base-color6 p$ P I7 d+ n) `, t, R
ask patches
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5 b; m5 Q8 a+ \3 A1 C set intersection? false1 f9 H) F) w0 N d+ }1 n
set auto? false
c! @+ [0 b* i1 e set green-light-up? true8 h) T" n* | M/ k9 l
set my-row -1$ F& U1 A5 J8 V2 X
set my-column -1+ r) M# W2 }4 i' T4 P6 q8 l7 `+ Q
set my-phase -17 o4 X5 S' M# {
set pcolor brown + 3: F: `/ x+ c6 K# g( z
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;; initialize the global variables that hold patch agentsets/ t+ ]' W9 U8 a: K- @$ \0 l7 B
set roads patches with( }/ \: n9 z b2 j
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
2 J' Z/ w2 j5 D5 j; q- S (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 H$ ^9 ?: p6 a7 a: ~' D6 S9 c; r set intersections roads with( v7 @, _, F0 w$ Z$ ] m2 v
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and4 ]: D, z! g0 o: j" M
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]* F- _) m& B$ `7 P) f0 \5 n
setup-intersections3 E7 U7 k5 G- G1 Z3 t1 y
end
5 J( N3 m x: ], ]! A# n, C$ u2 T其中定义道路的句子,如下所示,是什么意思啊?
/ F Q. ]+ ~( S" w4 q! i \ set roads patches with
A7 L- L Y) C( z* V: a* r [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or5 Y) m; u* J J/ @' h9 ^
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]: c+ M1 b' d: j1 m" x
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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