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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 N( w8 D/ O( O- P: Mnetlogo自带的social science--traffic grid这一例子当中,
( b1 T5 x& S+ e( jglobals& t% O/ ~+ \8 S* c' j @* E& t. g* p
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3 c0 C& L6 v& V7 `+ \0 q& C grid-x-inc ;; the amount of patches in between two roads in the x direction
x0 }5 x9 |) G' Z9 o. {. o7 i grid-y-inc ;; the amount of patches in between two roads in the y direction
! F0 K+ F7 C( P+ I. ~ acceleration ;; the constant that controls how much a car speeds up or slows down by if
. p( T- S8 G! Q( n" A8 i ;; it is to accelerate or decelerate
/ d+ f y M+ @0 n3 d7 u phase ;; keeps track of the phase
; r) ~8 h& M! n- c; E num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure7 n @$ _5 Y- V% W
current-light ;; the currently selected light/ ?' E* W. m% e1 ^
8 v# \3 R. k9 K2 C4 b: ? ;; patch agentsets8 f# k( I y5 y+ N' ~
intersections ;; agentset containing the patches that are intersections. r7 T- d1 G& {# g
roads ;; agentset containing the patches that are roads
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turtles-own6 X( C5 \$ i9 x9 ?+ T
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speed ;; the speed of the turtle
" O. [9 q4 _9 d: M% f. x, [ up-car? ;; true if the turtle moves downwards and false if it moves to the right
. E, f+ }5 ]& j# V3 f1 A wait-time ;; the amount of time since the last time a turtle has moved
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! f6 r+ _' R" G/ r% [/ Ypatches-own2 o0 s7 R# i# O4 r
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intersection? ;; true if the patch is at the intersection of two roads" v9 {' _/ s( o% j i; M# S
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
* r* X/ t2 x- Y- n4 Z8 ` ;; false for a non-intersection patches.
% Q# l* ]$ E6 g( V3 h, j; c2 n my-row ;; the row of the intersection counting from the upper left corner of the
/ a; p. g" @& i1 W ;; world. -1 for non-intersection patches., e' P8 d2 ^+ r& z' n' P
my-column ;; the column of the intersection counting from the upper left corner of the
1 R* U+ c+ e1 @' v ;; world. -1 for non-intersection patches.$ g/ T' f: T/ R. o8 h& i7 C) |
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
3 @# p. |, a( K* l6 d) e auto? ;; whether or not this intersection will switch automatically.6 n8 {: u3 [: U+ b( o
;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;# N: Z7 h" ?9 Q% L
;; Setup Procedures ;;
2 y, e9 C1 |1 e5 \ q9 I2 n% H;;;;;;;;;;;;;;;;;;;;;;, c y5 G) d3 A# z. V) d
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;; Initialize the display by giving the global and patch variables initial values.
( {3 R" Y3 w8 k ?0 j! k( c8 _8 S;; Create num-cars of turtles if there are enough road patches for one turtle to% O3 h5 Y, r7 Q1 |9 \
;; be created per road patch. Set up the plots.& ?7 E! x! p; S" C
to setup
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setup-globals( `5 g( \/ B9 |1 N& U
1 O9 {2 n8 B# Y+ j ;; First we ask the patches to draw themselves and set up a few variables
& {6 o- N) y5 E5 |1 i setup-patches: S7 L- @- f+ T" ?
make-current one-of intersections
2 A* ^/ y; F1 p label-current8 {1 t6 B6 a. e+ h$ M
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set-default-shape turtles "car"
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: A( t# F# J o! c4 ~ if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "
& U! L( _7 o4 \5 v" h7 v, ^, w7 C "road. Either increase the amount of roads ". S- H. F4 j4 [( [
"by increasing the GRID-SIZE-X or "4 [0 b. X7 O+ ^& r! ~
"GRID-SIZE-Y sliders, or decrease the "& ^# o9 m7 ^: C- q X) B
"number of cars by lowering the NUMBER slider.\n"
+ Q: x* |# p3 \7 z "The setup has stopped."), x9 z9 X& E0 F; w# C1 m1 R V
stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color1 J( W8 X% O" V1 T, ?; J( o$ h6 X) c
crt num-cars, l: h( w, I! f$ z
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( \! k/ Y$ @3 _ setup-cars
# n9 n& d. \2 q) P" b+ J4 P( G set-car-color
5 X3 [( \ C+ E5 ^9 N record-data8 z- I) x! @: a
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;; give the turtles an initial speed
" }& v: m+ A" f% }) F3 v ask turtles [ set-car-speed ]' @* |" W9 \" l; f
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reset-ticks
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;; Initialize the global variables to appropriate values
1 b" E3 Q& W- w3 Z( Z9 T. q( _% K; U mto setup-globals
! z! O+ }2 H* q! X& o/ ]" z set current-light nobody ;; just for now, since there are no lights yet. P# j; f5 r- a. i4 h. e
set phase 0
: R& e3 i) A9 ] |5 X$ Q+ v+ Q& M set num-cars-stopped 0
* y/ K8 \/ t+ X9 H set grid-x-inc world-width / grid-size-x
& `5 W) O& I/ _1 N, V' y0 E set grid-y-inc world-height / grid-size-y5 v* ?6 d& T& N6 {6 U
7 m& J) ?7 S1 r ^% O j( o6 n ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary, I- G) U9 V: ~0 [; [% q( a1 P
set acceleration 0.099
$ C/ }) R4 w ^1 b! U# @end. J1 P! V( f0 v. Y# u: Q. r
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
/ h" u9 w) ?- }/ k0 A( O$ o; M;; and initialize the traffic lights to one setting% z( D6 Z, [0 O- g$ J0 U! B' U: [
to setup-patches
0 w) ^1 Q6 Q5 y& }+ C ;; initialize the patch-owned variables and color the patches to a base-color
. O+ Y9 W1 `, M0 [1 i' q/ e ask patches
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4 e; C, I) `8 f: d9 G- K set intersection? false
7 j# R- m" u* c$ c2 t' q, m set auto? false
# O' {* I( Q9 C' w set green-light-up? true5 m" p4 W2 o6 f4 U/ s5 d5 E/ `# @ d
set my-row -1
; T' Z0 u; G; q4 c6 x set my-column -1
/ G! R/ r2 s0 t: J# B set my-phase -1
& j. W8 c& I! s p set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets
0 o9 p U+ v8 P) y/ k9 }" a, r) B set roads patches with
# H7 n% j6 W+ M* ~ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or M3 ]7 _" `) m! Y' z. @
(floor((pycor + max-pycor) mod grid-y-inc) = 0)] V9 }; l% ^' j9 I! A; r
set intersections roads with
) f( w! i2 { v) A' ^+ K& k [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
; u& ~; N/ g; u2 G/ @ (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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, B8 m( o9 H; x e' N$ t ask roads [ set pcolor white ]
% T. M* D) D# `% k' u2 p& n setup-intersections
# C# _! q/ e- a8 {7 l- Xend
a$ Z" o6 A, Q ^5 V4 T其中定义道路的句子,如下所示,是什么意思啊?
2 ]: X5 R. k- T. D V set roads patches with
; L7 o- J9 a; C$ W [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or0 K9 P4 U# K# a3 s+ ], K; q( _
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
1 Z& `, I% s' k( X$ H) d. }5 N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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