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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。6 ?7 C) f: T6 r
netlogo自带的social science--traffic grid这一例子当中,
. r! D- F% G( l8 W% Kglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction% _ _, P5 H7 g2 R2 g% O$ t8 ]4 f
grid-y-inc ;; the amount of patches in between two roads in the y direction* j/ c% a* }1 P. S) l6 l- Z. [. f/ s% ^
acceleration ;; the constant that controls how much a car speeds up or slows down by if
% ~9 H4 O+ r$ r6 ^: ^ s6 a ;; it is to accelerate or decelerate
- j; r9 \7 K& Z2 |9 f phase ;; keeps track of the phase# ]) Q8 V5 C: i. u
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure( T: P0 S# ]8 X' M
current-light ;; the currently selected light
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) P* Z# f0 j! U N# z' U ;; patch agentsets, I. v v7 h F. L
intersections ;; agentset containing the patches that are intersections/ ~: a. o/ V7 i7 Q
roads ;; agentset containing the patches that are roads
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turtles-own! s) q, f+ t+ L
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speed ;; the speed of the turtle+ Y9 d3 D. @# G/ o
up-car? ;; true if the turtle moves downwards and false if it moves to the right( `. q4 m# M3 P4 B3 k1 L) ^
wait-time ;; the amount of time since the last time a turtle has moved
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( v6 K9 c3 ~5 a7 h5 S# fpatches-own
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# u1 ?/ S0 D! S( a* y" @ intersection? ;; true if the patch is at the intersection of two roads& T: I- O; D( g1 `4 M# Y; ?
green-light-up? ;; true if the green light is above the intersection. otherwise, false./ q/ N3 ^# a0 U7 t
;; false for a non-intersection patches.+ X2 m+ w% Z; p% k
my-row ;; the row of the intersection counting from the upper left corner of the# q1 d) N! I# R3 ~ v7 O
;; world. -1 for non-intersection patches.
$ b7 Q6 s" O0 G* ]9 Y& \5 C1 N my-column ;; the column of the intersection counting from the upper left corner of the) L) A1 ]7 W- _/ G/ Q; D
;; world. -1 for non-intersection patches.( B0 X: {! U7 T: k6 f8 S
my-phase ;; the phase for the intersection. -1 for non-intersection patches.+ \! `% p: Z V% B) c+ S
auto? ;; whether or not this intersection will switch automatically.
4 U" ?. _1 o2 Z& s& l ;; false for non-intersection patches.
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" U* x0 m- M8 ]6 U9 X2 O;;;;;;;;;;;;;;;;;;;;;;
: q' k" `( P q- \, W# u p# [;; Setup Procedures ;;3 ?- @/ {4 y- V" T4 u$ J
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;; Initialize the display by giving the global and patch variables initial values.$ m. ~# u# O. D% m
;; Create num-cars of turtles if there are enough road patches for one turtle to
% f" r6 o' O+ D3 {+ D8 l+ G3 j;; be created per road patch. Set up the plots.
( q& O4 t/ k \ I/ ^to setup, e1 H, S0 G. r& n
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setup-globals- G. z0 p# `! D- X% x0 |# [
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;; First we ask the patches to draw themselves and set up a few variables
j4 R3 u- r- M N/ X5 B5 s setup-patches5 i; u: s J1 a3 `
make-current one-of intersections2 t: T, I9 e" ]
label-current
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set-default-shape turtles "car"; ?4 G' |4 B& p3 M
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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 "; C! T4 w& n& p- Z
"road. Either increase the amount of roads ": [7 n* A/ Y$ a
"by increasing the GRID-SIZE-X or "
% M- U, h7 \6 s* M8 A" T "GRID-SIZE-Y sliders, or decrease the "7 `, j+ E% p2 W) C
"number of cars by lowering the NUMBER slider.\n"
- ^ m6 ~3 c" ?) w2 g; W4 G "The setup has stopped.")
f' a& j5 g9 ]& B stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color4 e! r, o# L" N& X
crt num-cars
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* }! m, ~* z& M4 K8 x1 n& B% D setup-cars
; _2 }2 `( j$ A' e" ?, ] set-car-color
0 P2 D; y4 Z6 i4 K; C/ l% N record-data; `/ f# x& U. D* _
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/ Q6 k4 k, z% A2 j( X+ ^ \ ;; give the turtles an initial speed! E+ l4 \8 J% e
ask turtles [ set-car-speed ]8 @1 q# P; F+ w' K) ^9 J
# ? o( h/ q: i; t2 X3 ^ reset-ticks
' t+ R1 C! M7 L8 g% e. z0 N! X# k: Gend
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;; Initialize the global variables to appropriate values
" F& G: h6 t5 u& T7 Jto setup-globals. V+ p0 ?$ @6 S$ r$ k
set current-light nobody ;; just for now, since there are no lights yet
; }, \* H" w k j set phase 0% d5 e. t* k# C0 ~7 t0 b) M
set num-cars-stopped 0
) b& ]( B/ U! g2 Q/ S set grid-x-inc world-width / grid-size-x! i1 z8 X5 D- S1 e2 u
set grid-y-inc world-height / grid-size-y R. Z2 Q0 A- |, l6 b: j, j7 \
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary; g2 }9 V% [4 v7 J) k1 q0 P
set acceleration 0.099% \7 Z" T, L/ `' b0 m5 W
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
' W6 w% a4 S5 j: L;; and initialize the traffic lights to one setting
0 e4 }/ \4 t: m5 z* I- |! H0 fto setup-patches
' A1 ^8 |6 ^& b ;; initialize the patch-owned variables and color the patches to a base-color7 b" f* A2 b2 k5 G. \. A8 t
ask patches
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set intersection? false
* V: U4 f- }2 a& u) A) t set auto? false
$ B4 q% r/ l( V9 Y. c/ R6 K set green-light-up? true/ P2 d0 k' j P* J6 d
set my-row -1
/ z; C; m+ {3 R& g& V2 X% q set my-column -15 I3 L% G" y0 G4 z* K" C
set my-phase -1
7 d5 V8 i' D! W# G0 B$ v. H set pcolor brown + 3$ B) g b/ ]2 v6 y8 e
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;; initialize the global variables that hold patch agentsets
/ B6 z0 ]. ^; f set roads patches with
d* e4 q6 Z+ z9 W. o* o+ g6 z [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or: z8 N3 G* l `& }1 u
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
! e/ v) ^& {4 s e; L set intersections roads with
( l9 `% k! T& g; G [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and$ L8 @5 K* I; `$ O F
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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( J8 ~& P$ d- S1 W' n0 O* [ 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?
+ O8 ~2 g: ]( k. f set roads patches with! v+ i$ a- k2 c
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
. Q2 q1 S% \( ? (floor((pycor + max-pycor) mod grid-y-inc) = 0)]2 i% x; u* v2 W* C4 d
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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