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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。9 _0 e$ ]' n; [. g" f7 C
netlogo自带的social science--traffic grid这一例子当中,
# K+ G4 Z# p9 `5 aglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction
! G, \3 }4 n' W: [2 d: M% b grid-y-inc ;; the amount of patches in between two roads in the y direction" J$ b6 j; o7 U. q0 |6 h9 [ q; I0 _
acceleration ;; the constant that controls how much a car speeds up or slows down by if
0 `7 R w" }. {& n ;; it is to accelerate or decelerate/ [3 S! V1 Y, V# S
phase ;; keeps track of the phase& s: l: w n+ f
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure: ]' u6 Q( @" o) q# G, M1 X' u$ ?% g; i
current-light ;; the currently selected light4 O9 u- `1 W8 ~$ D2 R* L$ H/ {$ N
8 |0 @$ G* ?9 ?" R. b ;; patch agentsets
8 N! a% Z- g9 l9 i" R/ P intersections ;; agentset containing the patches that are intersections( m" H# v, E0 E. M) L8 h; b
roads ;; agentset containing the patches that are roads
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y8 H: z. a- j7 `' U8 H% K5 fturtles-own
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speed ;; the speed of the turtle
8 C9 Z3 Q; m5 w; t' E up-car? ;; true if the turtle moves downwards and false if it moves to the right
: }; x, @3 ]) I3 Q- ^+ w5 H9 Q7 P wait-time ;; the amount of time since the last time a turtle has moved0 C* j d( T, z) h
]
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads
% g4 G9 ?0 p6 N' l" U" I; q green-light-up? ;; true if the green light is above the intersection. otherwise, false.2 C5 s9 @" i. O) a
;; false for a non-intersection patches.$ `% s) ?3 i$ I4 Q' H
my-row ;; the row of the intersection counting from the upper left corner of the
' w. @* C3 l! s; T7 A ;; world. -1 for non-intersection patches.; ?: F$ G" Z0 k7 u
my-column ;; the column of the intersection counting from the upper left corner of the
) }# v% {6 v8 b8 s) U/ B9 O @ ;; world. -1 for non-intersection patches.. M8 |4 Q1 W7 q( n+ d
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
* X% `4 m, X& c auto? ;; whether or not this intersection will switch automatically.
3 T5 d2 A! e- T$ d. R; L3 Z, | ;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;. r* ]/ D( g# i( X
;; Setup Procedures ;;% E' w4 C( k" d/ p. c- {7 B3 I8 R
;;;;;;;;;;;;;;;;;;;;;;7 g! {$ e/ T8 R) y
9 X7 Y, ]- J& h+ i) M;; Initialize the display by giving the global and patch variables initial values.: L* n1 Q9 R3 o @( _7 y" Z
;; Create num-cars of turtles if there are enough road patches for one turtle to& b) t+ H- ^' A5 E% c
;; be created per road patch. Set up the plots.& h, w% `5 u7 E' G+ L& x' A* F
to setup
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( z2 j9 H: `, ]8 ]8 `) X; S setup-globals: X" v& I$ h! Q4 a3 H
' q! ]; R8 K9 a2 L6 A% H1 @( B* _6 n ;; First we ask the patches to draw themselves and set up a few variables/ a, C, N( l7 Z; S9 F7 n- a7 W
setup-patches
{& U; a9 f, C3 e& J+ A2 v0 l make-current one-of intersections
- E1 P/ C1 R2 r' T& ]: T label-current/ z2 K) F/ L! k \) N8 l7 a, h0 R0 j
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set-default-shape turtles "car"+ [# U% `, N8 S) U9 p9 c
" u+ \0 v- Q+ V* t' S if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "
4 C3 o$ J* d) ^ "road. Either increase the amount of roads "0 ~8 c8 N2 q; h3 V& {9 o
"by increasing the GRID-SIZE-X or "& j( Q M6 M: y0 Z$ Q
"GRID-SIZE-Y sliders, or decrease the "
" _5 d7 y& }! h k3 H* j "number of cars by lowering the NUMBER slider.\n"
$ K& m& S/ o( [, W2 ~& T6 ] "The setup has stopped.")2 k; C g, g3 [2 ^! \
stop
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1 X A& U8 a+ [& f9 y! U" d ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color# H. h @; L) p
crt num-cars" R7 v- F$ d" r
[
3 g3 V% M9 Y( W! I6 O setup-cars
; p6 \& n$ ?) H* R set-car-color
% A2 Q0 w9 p1 c9 P% B record-data1 y0 V e4 \( A2 a0 u
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;; give the turtles an initial speed/ \! Q0 Q" H$ I. B9 j$ ~& S
ask turtles [ set-car-speed ]
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reset-ticks
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;; Initialize the global variables to appropriate values
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( f8 N5 Z% `7 O! G set current-light nobody ;; just for now, since there are no lights yet
$ ~3 p0 R+ k% x" O4 ~ set phase 0
1 y. K# D) o& i8 Q set num-cars-stopped 0
% N3 M3 |; h) \& N set grid-x-inc world-width / grid-size-x9 S: v0 `) e; q# B2 x( u4 D2 u
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 boundary
3 X) k9 f( u; e1 d a7 ^; L b set acceleration 0.099- [* n, N/ b: {% o
end
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3 h( W9 V) R& y# s4 F;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
0 j$ ^* ^7 ]( M9 y, W$ @' |0 l& @;; and initialize the traffic lights to one setting( ]; Z$ K. J8 F4 P2 m
to setup-patches1 U7 k9 ^6 p" t0 w0 r* z
;; initialize the patch-owned variables and color the patches to a base-color- r+ y2 I) O5 V( |( I. R; H
ask patches, s( S' X% o( { Y: _
[
! Q# `% T4 p' T3 Y/ @% G set intersection? false# l, G W, a7 P; i o. [$ ?4 w
set auto? false
+ U' O6 } l. n6 c/ }7 n3 r set green-light-up? true
; f4 Z1 }/ m+ i2 O set my-row -14 W" J8 r+ e) T y% j: f2 M
set my-column -1
% x- s. J' @( g6 Z7 Z- C4 N; w4 ] set my-phase -16 O! X0 ^9 v2 R9 {: O) Q/ J* e. P! Z
set pcolor brown + 3" E9 H. A* Z5 D! _( t
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" l% h2 ]; c8 s7 O ;; initialize the global variables that hold patch agentsets1 e7 w/ C5 F/ W3 h5 i. L. x
set roads patches with
# z D+ x7 D& Y2 o' p5 m [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
- ^6 ^! n# h0 h8 k9 g% s (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
8 `7 f$ U. t2 \. T1 c- I$ a3 I4 L9 y set intersections roads with
5 {+ X! P3 g* o) }' h0 L# Q [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and) |* V, @( e$ [0 e6 D# k
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]& B& z- e3 P4 Q3 a
. \+ s/ ?1 m8 ~0 l7 C ask roads [ set pcolor white ]) w0 M) y) ]2 A2 [, I
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?
7 D) x+ u3 b( w6 C0 o set roads patches with
4 ]; O- H5 t" N; C, q [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
$ S; h' W+ e1 }5 J( g8 B (floor((pycor + max-pycor) mod grid-y-inc) = 0)]; Z, N. U4 B4 X! v8 [+ U$ K/ c
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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