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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。
4 B. ~1 m1 w0 }# z% E- f# Pnetlogo自带的social science--traffic grid这一例子当中,
% L9 m9 z( @, Pglobals5 `7 u- [- b8 L
[
7 E2 p4 B1 W* B grid-x-inc ;; the amount of patches in between two roads in the x direction
+ ~0 t+ O d1 n$ u grid-y-inc ;; the amount of patches in between two roads in the y direction$ }) s7 r& @' A. R, P8 s/ q6 y
acceleration ;; the constant that controls how much a car speeds up or slows down by if
+ p7 {2 M# {. l: i7 I ;; it is to accelerate or decelerate
; @) w" O0 H* m( Q! I; N* C phase ;; keeps track of the phase
% h+ B, `" U1 T# _/ @2 k num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
0 B1 r! W4 {& W7 |" k, j7 K! G' y current-light ;; the currently selected light
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;; patch agentsets
1 f, o* v' k$ q* I$ g7 Z" B intersections ;; agentset containing the patches that are intersections* z" H' @8 f- Q' G. Z: k! p" M5 U
roads ;; agentset containing the patches that are roads
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( X, g, M- M* A/ Z3 Q3 o1 b' c4 R& {turtles-own
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% s9 ^1 H4 w x7 v9 j% b+ U# ] speed ;; the speed of the turtle! B- U/ D( Z3 Y) b1 S3 j) z: Y
up-car? ;; true if the turtle moves downwards and false if it moves to the right6 y$ v s, S& y, E+ C/ n2 u; o
wait-time ;; the amount of time since the last time a turtle has moved6 c! L v4 s3 B# F. K7 ~
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patches-own
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- P8 Z! v$ M y: o intersection? ;; true if the patch is at the intersection of two roads
$ _8 X7 y( N w# f3 t4 A9 n M green-light-up? ;; true if the green light is above the intersection. otherwise, false.$ Q, g3 i+ p; q( R" L% ] [
;; false for a non-intersection patches.5 f. t% m: U7 u! G
my-row ;; the row of the intersection counting from the upper left corner of the) a* W3 G1 t* v2 @9 [: Q# M+ i
;; world. -1 for non-intersection patches.
0 n5 l. z8 x5 ], |$ L my-column ;; the column of the intersection counting from the upper left corner of the) `2 d' u# f$ U. c( S: }( R v
;; world. -1 for non-intersection patches.
$ }7 S1 G# q* @0 ^ my-phase ;; the phase for the intersection. -1 for non-intersection patches.# q6 R! c) Q! ~2 w8 }! e
auto? ;; whether or not this intersection will switch automatically. F( @4 J4 B5 R3 `& u/ b$ k7 M6 n, k. w
;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;2 R$ G* y6 H& y# o8 Y0 _4 J
;; Setup Procedures ;;
, a! l* z* i, w% M0 `- b- x;;;;;;;;;;;;;;;;;;;;;;$ O8 D0 Q4 l1 C' J% P$ [1 T8 U2 M
9 {/ o! J4 J: `4 \- m$ B;; Initialize the display by giving the global and patch variables initial values.! I0 u; ] b% k% }
;; Create num-cars of turtles if there are enough road patches for one turtle to# n! h5 I" f- f4 M. D/ ^
;; be created per road patch. Set up the plots.
+ b' l5 A7 b; y# v) N! v2 pto setup( e# G; V$ b6 t. `, q4 B
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setup-globals
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;; First we ask the patches to draw themselves and set up a few variables
6 a: f+ z, f7 O4 m7 j0 m4 E( o setup-patches
2 b- ~6 [5 j( Q8 q( g: C make-current one-of intersections# v" `1 V! U2 f; l
label-current
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3 G/ B* p: R$ z/ I- M3 ]2 X set-default-shape turtles "car"8 {& V7 N! o- V+ s0 j
* Z* ]4 ^/ F C1 \* X4 F6 { if (num-cars > count roads)$ q) j: T0 h) c8 K Q# t! t! [ \
[
1 T4 \: M+ @! ^. A user-message (word "There are too many cars for the amount of "
2 p* _* _3 V8 p$ |) y "road. Either increase the amount of roads "/ k0 {( u& Y6 S/ `" d) W( j6 N
"by increasing the GRID-SIZE-X or "$ m+ v* C$ V. x
"GRID-SIZE-Y sliders, or decrease the "
( ^- S- p6 B3 V) Q3 Q4 o "number of cars by lowering the NUMBER slider.\n"" T$ c1 v y9 K: b* t
"The setup has stopped.")9 A5 `+ I5 f$ ?' r5 ~
stop
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+ S- b8 ?! i4 ]
, F# u! B! x+ _5 |" F" O" Q/ O ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color5 }( q7 K& _2 m
crt num-cars+ R1 |( a6 J9 n
[
+ ?! I k4 ]$ B) e- s3 ~ setup-cars" R7 i& W8 \, L; J) _( [2 @1 j/ Z5 \
set-car-color0 a; g! w$ b K/ ~# `- R; A3 w3 {1 F4 k
record-data
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3 k9 n/ K+ }, F i7 C; }% }
;; give the turtles an initial speed
/ H) E4 `7 ]1 z& J ask turtles [ set-car-speed ], A% A7 K% G8 d
( ^. b' T# f# m, a8 a: d+ D% q w reset-ticks% P- B+ D+ m! C. E7 r8 y0 g' `
end
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;; Initialize the global variables to appropriate values) t7 }8 ?. X$ b" K
to setup-globals
8 t) x% k8 h X% x7 P set current-light nobody ;; just for now, since there are no lights yet
" b. ^2 D- u0 S" x, T) O L set phase 0
+ k% x1 q2 X1 `+ Q$ t set num-cars-stopped 0( n! b4 o" N% T7 r4 z7 I2 u6 q
set grid-x-inc world-width / grid-size-x# B# ^, f" ^* N ^- d3 L5 e
set grid-y-inc world-height / grid-size-y/ a" F7 s1 I/ Q& t( |
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary, V' X s! b4 K5 B7 l9 H7 e
set acceleration 0.099$ a e X+ s0 ]
end# K" l5 I# f, v% a/ i
5 w) j- Y1 t4 @, Z; S;; Make the patches have appropriate colors, set up the roads and intersections agentsets,( k$ _& N; _2 v
;; and initialize the traffic lights to one setting- R8 O$ l. w6 ~7 q' H
to setup-patches
+ `* ^, k1 h- |2 b, [ ;; initialize the patch-owned variables and color the patches to a base-color- Y, H0 b5 `( o4 E h2 Q, c
ask patches2 k9 P; u( F3 R1 }; C9 R/ |
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& f# W& @9 Y, B. @& H set intersection? false
' |4 m% x9 i; t set auto? false9 q: q( c4 W e0 k6 l
set green-light-up? true ?/ W: [0 u' U1 Y1 Q
set my-row -1
3 F0 o. G; q( y& q set my-column -1
2 X2 i! r9 |& j+ G+ S6 N set my-phase -1. ~/ L4 Q7 y/ F
set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets$ u: A2 u7 e1 L6 }& e0 q0 X( Q2 ]. I
set roads patches with
* e! f r1 }7 W6 w' z [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or* ?* C5 D" @! b8 I" \1 D
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]* i) j& m+ n( p8 C! O
set intersections roads with
! I8 n0 t* Y4 t: W7 M/ y [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and3 `1 G5 R$ n! U5 | R
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]( [' J+ [/ _- }( Q+ ~2 w: t* C5 o
setup-intersections
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# G+ i. k8 N- w1 }( Z! [, s其中定义道路的句子,如下所示,是什么意思啊?
% h7 B* G- k9 _7 w }0 t set roads patches with5 J' ? b. i% m- r" \$ x
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
: D- K' Q3 h, Y1 ^6 C) C (floor((pycor + max-pycor) mod grid-y-inc) = 0)]1 t; Z% { t. P4 [# x( Q
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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