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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。" x6 F0 Q! O* {) ]
netlogo自带的social science--traffic grid这一例子当中,
" W6 A3 d: k _! ]globals9 k1 u& j/ B& P' }! w
[
' @& U. @5 {: d9 W) P' b2 N grid-x-inc ;; the amount of patches in between two roads in the x direction
! }7 s8 `9 T- r) z4 T3 O grid-y-inc ;; the amount of patches in between two roads in the y direction
( @" ^% L2 G+ e0 w2 c* ~% U% v$ k0 ~ acceleration ;; the constant that controls how much a car speeds up or slows down by if8 o+ Q4 t; R7 U( K' b' G
;; it is to accelerate or decelerate
- g) g( R! f8 ]+ ]. `8 Q0 v phase ;; keeps track of the phase
5 l; ]$ ?. z& R' Y' Y! X$ g/ c num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure# A# b1 v" F. W3 R' n
current-light ;; the currently selected light
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;; patch agentsets# |2 b D6 o+ I
intersections ;; agentset containing the patches that are intersections
/ y& q0 e3 m" {* p; R' ] roads ;; agentset containing the patches that are roads
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turtles-own
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( U* o' A$ r8 p5 ] speed ;; the speed of the turtle
" c* T* _- D' T; F, } up-car? ;; true if the turtle moves downwards and false if it moves to the right8 P; s# Q( {' f$ o: n
wait-time ;; the amount of time since the last time a turtle has moved: }5 o- C; Z7 K5 v
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N( {, Q9 A3 f3 E! o: O; mpatches-own5 T% d4 O" F, n6 a. p( A
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3 ]0 g7 p) @% e, _" J" Q- |% U intersection? ;; true if the patch is at the intersection of two roads4 O, U# J8 R% z6 P1 ~7 F# q0 c# ?& H
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
, L7 }, W* x, c+ r. K ;; false for a non-intersection patches.
; J. o& I0 u% h2 z; X `8 o my-row ;; the row of the intersection counting from the upper left corner of the6 Z: J) W! E2 M& }1 ~3 i% G
;; world. -1 for non-intersection patches.: p- y/ a) G. q- E, Q S5 v
my-column ;; the column of the intersection counting from the upper left corner of the# ~. R) D2 U- O8 I% G }
;; world. -1 for non-intersection patches.5 r2 M; g3 o" ^# x2 P! A- C6 d
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
2 _% X' f1 k% L: g; ?; K auto? ;; whether or not this intersection will switch automatically.2 w# c* \7 p& G; c* E
;; false for non-intersection patches.0 l. {/ {" q7 }7 A( V
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6 K1 s8 ]! @1 z: B0 C. g;;;;;;;;;;;;;;;;;;;;;;2 x( |' f# ]3 S. N- x0 I
;; Setup Procedures ;;5 j" m* ~6 M4 ^& [# E# W2 l/ `( ]
;;;;;;;;;;;;;;;;;;;;;;
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;; Initialize the display by giving the global and patch variables initial values.
5 f3 {- p: E. G5 A; E. i;; Create num-cars of turtles if there are enough road patches for one turtle to; A/ q, G, s2 ~: o) ]' M+ b( F9 L
;; be created per road patch. Set up the plots.
. X) I% {- g4 a. m: q* Dto setup
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- C K. A% K' V8 E" ? setup-globals
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8 p9 U) A7 K5 ]8 D5 v ;; First we ask the patches to draw themselves and set up a few variables- E8 |" k5 ]% x! e! k
setup-patches
* N# o1 r2 [0 y% S3 B" F make-current one-of intersections
" P+ V. S3 }( y3 p label-current
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) g# Y! J+ {3 r2 W0 v* A6 X set-default-shape turtles "car"
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if (num-cars > count roads): |" J ?2 v. h K
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user-message (word "There are too many cars for the amount of "
! |8 o& O' f% \ v2 d% Y "road. Either increase the amount of roads "0 p' m* D' K/ r
"by increasing the GRID-SIZE-X or "
( d1 a0 i& e3 S2 m9 u) B" X "GRID-SIZE-Y sliders, or decrease the "
1 ~; A# I+ H2 W5 j6 P! ?/ ~ "number of cars by lowering the NUMBER slider.\n"% H6 ~6 A$ M3 ]0 ^6 y) P
"The setup has stopped.")
, w9 g& E1 F1 w7 A! z# S4 Z W stop$ @8 K3 S& t6 a2 c
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) Y/ i2 Q% c6 k& J# r. r0 { ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
6 o# G3 @! A+ q crt num-cars
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setup-cars' K5 }* t" M- b) E
set-car-color: a+ |( K/ l) {+ |# G) z
record-data' i# _! g1 O3 P3 F
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0 J- p& z* e8 n5 u# M3 m8 H% ?: ` ;; give the turtles an initial speed1 f) u# c. `6 v4 Z+ G) |/ C
ask turtles [ set-car-speed ]
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# A6 E6 Q I# N( ~5 q; b0 ] reset-ticks
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;; Initialize the global variables to appropriate values) F) A( f; \% [$ t; g3 N
to setup-globals
' w' b; f9 H9 X! R set current-light nobody ;; just for now, since there are no lights yet6 @2 I4 P! Q' B: X3 ?* X- \7 Y% [
set phase 0
: Q' R. U4 i8 A9 q set num-cars-stopped 0; ]1 |+ f) e7 W" j$ j
set grid-x-inc world-width / grid-size-x7 Q9 g- \) k* b9 S/ G5 ?
set grid-y-inc world-height / grid-size-y {. a/ l: W* I" j7 T
; e( v. A4 {; ~3 w ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary% C0 Z3 K4 U+ M) O
set acceleration 0.0991 f" u! I/ R- g2 q
end) Y! t" l9 d. s6 N$ M. t% w- s; D* w
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,! _ }( T0 n1 p- {: S" {
;; and initialize the traffic lights to one setting
% U4 a4 Z( Y0 N+ i; _to setup-patches7 O4 O+ W9 i" x& q) K% m! F
;; initialize the patch-owned variables and color the patches to a base-color
( l; [! f) o' J/ z+ Q1 {: U ask patches1 b9 m2 j6 U9 Z( b
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1 [6 |2 Z Y+ U8 u/ D: Z set intersection? false# N. Q/ q/ \3 P5 v) y+ x" K9 {3 V
set auto? false
% g, a9 l& G' M6 L. K set green-light-up? true
/ I, b E7 W7 r+ j set my-row -1
! y7 o4 A- `; ?0 p% @' F! f set my-column -14 \ z" P; G3 q& S; u
set my-phase -1
0 K) \$ Z# C+ x( K, m/ Q set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets+ F' i( d9 y& R; z4 A/ Y
set roads patches with) J+ F" m0 E) ]) t" S' k
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
$ ?% M# x1 d% S# O% a (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 k9 L; b+ H6 V) F' a0 R/ I% p* h set intersections roads with
* I: b0 v, G8 I# |% K [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and, h0 @) f2 Q4 q
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]1 \: f# M2 b3 S1 F/ V! Z7 M, s. f
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ask roads [ set pcolor white ]
+ R J9 x8 i" n. ^ setup-intersections4 c* s P x; l) p# W. @% y0 Q
end
0 V/ c4 b5 r. _& R其中定义道路的句子,如下所示,是什么意思啊?; f- z9 T6 L& J) p0 K5 A: |' f
set roads patches with0 H& R- G1 }/ O {' F0 c' k: A
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or0 D% D1 ]$ X. a8 o( K8 e
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
3 ~) c P+ {# g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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