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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。! }8 j C* B' T2 U
netlogo自带的social science--traffic grid这一例子当中,
8 L+ v- U. k; f* n2 J0 Z) ^5 S. `globals6 T8 C6 J+ J$ S W5 T/ U
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grid-x-inc ;; the amount of patches in between two roads in the x direction
6 ~, l6 b0 r7 M grid-y-inc ;; the amount of patches in between two roads in the y direction p; o" r3 P' l6 V; A N, W
acceleration ;; the constant that controls how much a car speeds up or slows down by if
8 o, m% ^" k: y& i4 n" |6 {* R3 w ;; it is to accelerate or decelerate
( l* A: l5 H7 y$ ~* L phase ;; keeps track of the phase
4 q6 x# f# O4 x num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
, `: [9 ?) `6 u! M+ Y2 z current-light ;; the currently selected light0 x( L# p, J8 V/ }* A7 R6 C( P3 v
* m; e6 p. N) P& M4 ]$ D7 y& z, g0 t ;; patch agentsets
! j# X( m- r! j" Z# W) \ intersections ;; agentset containing the patches that are intersections7 j* C! @7 t/ O. j w
roads ;; agentset containing the patches that are roads0 B# N' s5 [! z) }' g) e' p
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turtles-own
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speed ;; the speed of the turtle
6 C' C' {3 i2 n2 I! C2 ] up-car? ;; true if the turtle moves downwards and false if it moves to the right
: }: ~) `8 Y1 `2 L8 ?5 n1 t! s2 V& F wait-time ;; the amount of time since the last time a turtle has moved* [/ |8 G. m, q1 T' }/ [5 x s
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads9 }* q% m8 v3 P3 T- a3 A
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
8 s" Q( B! w% |2 p. P3 S; j5 n* V ;; false for a non-intersection patches.7 a" i2 Z) ^' o3 C$ B( c% X2 f5 m
my-row ;; the row of the intersection counting from the upper left corner of the4 v' j2 E9 h7 X$ U, B2 t+ M! V
;; world. -1 for non-intersection patches.# q: B0 \0 x; m) I. Z+ i, Y
my-column ;; the column of the intersection counting from the upper left corner of the! H9 n% |; R, L8 }$ x$ S5 `* [9 X
;; world. -1 for non-intersection patches.
+ u- G; Y3 B" [" }$ ^$ B% X my-phase ;; the phase for the intersection. -1 for non-intersection patches.
4 H& k, ^5 L& a3 i* `* ] auto? ;; whether or not this intersection will switch automatically.+ p( n9 c* r/ j. s
;; false for non-intersection patches.
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6 ]/ q/ \8 a+ ]1 R3 g/ a;;;;;;;;;;;;;;;;;;;;;;
. ]4 x/ l" {/ D: e! R+ R& S" A;; Setup Procedures ;;
# D8 B% |- V; _( r( P( H1 h;;;;;;;;;;;;;;;;;;;;;;5 \& a% E3 y" _9 d: V3 b
7 w2 C/ [- }9 K; Y, R, ~;; Initialize the display by giving the global and patch variables initial values.' B0 g2 |/ o! \ |9 w% A0 x8 o+ X: P
;; Create num-cars of turtles if there are enough road patches for one turtle to
+ j, L. b$ K2 y) N;; be created per road patch. Set up the plots. m; q4 C7 o6 C) k8 A q# J5 p+ z4 j
to setup
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setup-globals
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;; First we ask the patches to draw themselves and set up a few variables
2 T5 \/ N4 ?8 U& A8 u# J* N setup-patches
) r* T' S7 w4 J, z make-current one-of intersections
. @8 G9 h+ N# o0 k5 e+ s label-current
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set-default-shape turtles "car"
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$ A2 N4 n& v' G9 T if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "
% t+ Y! u8 ] I) B "road. Either increase the amount of roads "3 o, u, R7 B8 T6 a+ o3 @/ O$ U
"by increasing the GRID-SIZE-X or "
' B, ~: Z: v0 @ |$ f "GRID-SIZE-Y sliders, or decrease the "
6 i& J* t1 E# v# L+ Z; _ "number of cars by lowering the NUMBER slider.\n", n8 D2 c; `* I6 m) A. I
"The setup has stopped.")
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" A. Y/ L* T2 \. A ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
6 t, _' n& `& b V. u. D crt num-cars4 {2 N2 f3 C, [* o
[
2 Z1 e1 Q4 U/ o$ z6 N setup-cars4 K7 M% y- u- V- I5 s, o+ s
set-car-color
% X" d1 A5 i7 \- P record-data( Q9 [0 a9 ~# W ]- R4 _
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;; give the turtles an initial speed0 E) _# p Y1 b2 p
ask turtles [ set-car-speed ]
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) o/ c. c5 }8 v% j# G reset-ticks
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;; Initialize the global variables to appropriate values! `* ^4 F! L5 a& v7 N
to setup-globals$ ^$ _) {: M9 O# H7 }! B8 A6 v
set current-light nobody ;; just for now, since there are no lights yet
( q4 i+ `0 |0 b, a set phase 0; a5 D m! K3 g; L+ z: g
set num-cars-stopped 01 l- |$ @' n. I# a- h
set grid-x-inc world-width / grid-size-x) H4 L1 ]7 x" v0 R% T+ D! J3 G
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
q% F5 K% j4 s set acceleration 0.0994 X: `" B+ x& R. R" E8 h. |. A* }
end. W w: m" h1 H3 C6 U: U! W
7 v; ^4 n# y+ ]# g3 r;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
u" D8 J' ^- I3 K; y# w! @;; and initialize the traffic lights to one setting
% D- Y+ b& F4 ~# W4 nto setup-patches" {: q% U/ c H: r; D: K, j" t
;; initialize the patch-owned variables and color the patches to a base-color. _1 U* L j& i6 d" _+ H% o( S; I
ask patches
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; H6 P& f) F# }- W8 L; } set intersection? false
& f2 j8 _( H& Z* ?! ` W4 h0 L set auto? false2 |! I, K' X0 H# a5 R
set green-light-up? true
* h7 y% V1 U* l. V! f7 ` set my-row -1( ?: D0 L' Z$ t; M5 r0 ]
set my-column -1 E! d9 Z% |* T- X; L) S+ G! _
set my-phase -1
T% t1 g2 P# f+ H+ H& s. z set pcolor brown + 3 M7 o. K v: a. }0 S* G# J: D( U
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;; initialize the global variables that hold patch agentsets; A5 L6 @% Y! Q. ^( G4 V. o
set roads patches with
D- K$ ` x+ M) Y V1 a [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or/ g- ?/ V0 c0 w3 v3 w2 J1 `5 E' r
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
! C* t8 T6 A4 W* s8 M, K- L {. y set intersections roads with1 ^5 K" ]- y% k! ^, h2 W
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and- w( g2 g" y) l" Z7 Z& q
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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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?
4 K2 m4 F; i9 [ set roads patches with
( _7 w( i2 ?8 P. o& J9 E( X [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or& E' l8 N6 z$ k& `& |
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
& @) a' O1 Y, _' J+ t8 z+ G8 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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