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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。* E0 a1 z# U8 t# T" y; a$ q& O
netlogo自带的social science--traffic grid这一例子当中,
2 u1 Y0 d; G! S" I1 nglobals
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3 \ C4 r4 J0 S; P. D! a8 ~ grid-x-inc ;; the amount of patches in between two roads in the x direction5 e! C$ N1 c# }" _0 D) [
grid-y-inc ;; the amount of patches in between two roads in the y direction3 q+ n! F0 m4 `
acceleration ;; the constant that controls how much a car speeds up or slows down by if
# @5 u- ^7 \( Z y; b ;; it is to accelerate or decelerate
6 v V1 d1 S+ x4 w" P8 { phase ;; keeps track of the phase; n. n5 z) N( k% q2 E* e3 {
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure9 R) A! X- }5 O, J. P" g) i
current-light ;; the currently selected light* y2 i) [3 R) D
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;; patch agentsets
7 W1 ~/ z8 n. X/ _+ u intersections ;; agentset containing the patches that are intersections
0 ^9 k/ c) O4 C; H3 F4 |' ^ roads ;; agentset containing the patches that are roads, T7 k8 O. s9 `: w
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turtles-own3 ?) N% c+ M6 R$ b: ~4 y- a
[
9 _5 u# y" Z) y& e speed ;; the speed of the turtle
" q1 |6 Y5 W# D( o9 d$ L/ ?# a# s up-car? ;; true if the turtle moves downwards and false if it moves to the right
( n7 K- Q* ?) ]8 { wait-time ;; the amount of time since the last time a turtle has moved# o* p" [. _& \6 M4 d$ J2 ~. o
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads
* a9 m* H0 |) g5 H; ?. ` green-light-up? ;; true if the green light is above the intersection. otherwise, false. Y/ u8 R+ d& P2 S
;; false for a non-intersection patches.
" Q2 J- U: i: {0 ]* v7 o0 ~: W my-row ;; the row of the intersection counting from the upper left corner of the
& r0 Y1 r- \9 V3 p/ F; g2 H! `: Z ;; world. -1 for non-intersection patches.) ?* T/ U+ }% L: p0 m% y
my-column ;; the column of the intersection counting from the upper left corner of the/ L! @8 S, P' a* z# s& U% i
;; world. -1 for non-intersection patches.
$ ]5 I4 k* Y2 ?9 }" F4 O my-phase ;; the phase for the intersection. -1 for non-intersection patches.
6 E" t9 R( o. U9 ^1 A auto? ;; whether or not this intersection will switch automatically.: x* v+ e K( ]' g/ d* w
;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;
6 G# n7 b1 C: U: _ D;; Setup Procedures ;;
% p3 R4 l* |1 u/ B;;;;;;;;;;;;;;;;;;;;;;
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* ~5 l2 M+ V7 s+ d- I* A;; Initialize the display by giving the global and patch variables initial values.
: f: }. P# Z. S1 P& N;; Create num-cars of turtles if there are enough road patches for one turtle to: m) N" R. V, L* q0 B1 G
;; be created per road patch. Set up the plots.
; q0 K9 K/ q4 `8 N( F$ I0 l3 dto setup
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! P5 x# U& l: g( t setup-globals |& [3 l* s* m' @
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;; First we ask the patches to draw themselves and set up a few variables. p% }! r) o5 `. P" n6 F; N
setup-patches
3 [' q, Q( _) u/ Z/ e make-current one-of intersections
- { Z% w9 [2 c* r' {) L' k( ~! \* i- R label-current. Y0 n i$ Z* W6 \* d
2 u6 d' }" e+ E1 c8 s& m, m set-default-shape turtles "car"
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& i9 c4 ?& L) N' c( | if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "2 D; Q; m: @" _
"road. Either increase the amount of roads "0 g+ N A y# s" B5 I ?% M8 m
"by increasing the GRID-SIZE-X or "2 y' _# L! T, {3 J; x1 k
"GRID-SIZE-Y sliders, or decrease the "
' L; {- |7 g: `2 k: Y "number of cars by lowering the NUMBER slider.\n"
* e% ]! C4 E! c! Z; Z @. w "The setup has stopped.")$ H. {6 q% G. m$ @; k1 y. \4 _
stop
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0 M K5 ?, y A& w, O5 B; R t1 K ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
& R: H' T" e) w crt num-cars4 `7 c6 \. L/ f% G8 ~* ^! p
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setup-cars# ]* G5 g1 N: q6 Z9 b8 C, B
set-car-color
% ^5 s% ?+ @" w6 g: B, V4 A record-data, N+ @/ }7 i p, r0 `; y. t" o
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;; give the turtles an initial speed6 t g! T/ J. u; F
ask turtles [ set-car-speed ]
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* E- ~& a# O2 }! f reset-ticks& Q# G# }4 Q7 Q1 [1 Z& O. Q
end) j, k! D2 j; d# ^
% ?, x+ W9 S3 z, w5 \2 l# T;; Initialize the global variables to appropriate values8 h' _0 f8 D4 t) n+ j
to setup-globals0 o5 g9 d# s0 N" o N$ J
set current-light nobody ;; just for now, since there are no lights yet8 @# r b3 v! Y: h5 n# I. s
set phase 02 ]& a: o/ x( F+ ~1 ?
set num-cars-stopped 0
- u' i% ^4 l9 ?6 X9 b: y, a4 I set grid-x-inc world-width / grid-size-x0 @6 b+ ?0 V/ @" m+ }$ V
set grid-y-inc world-height / grid-size-y1 Z# Y2 Q8 S& y# F- r4 z3 P
6 x" p; z- @4 H) t% i ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
. Z9 L2 r& h4 Y& T+ f set acceleration 0.0997 l$ g9 M) D7 g
end& Y. f% [- y2 K+ y
& c2 t3 `) _3 \# ^- Q$ H;; Make the patches have appropriate colors, set up the roads and intersections agentsets,2 }) @* y+ F$ z p- V' t6 |. a
;; and initialize the traffic lights to one setting
. v& ^; M! x/ o: Nto setup-patches
: R0 F1 L: G. [0 l( O* R ;; initialize the patch-owned variables and color the patches to a base-color
Z' b2 Q, [ ~ ask patches( Z% g* W1 `; R% `2 z" S
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set intersection? false/ i" K/ D& Z7 C% o. m \9 r% {
set auto? false
( y9 K% L0 Z7 q( I9 s. N set green-light-up? true0 w1 P1 E9 `) x' X+ }
set my-row -1% V# I" e' N/ Y; a2 Q
set my-column -1
5 g9 R1 w6 x5 P0 S5 d6 G$ I8 y8 Z( D set my-phase -1
) m/ l _- ^. }! u" I set pcolor brown + 3; a1 E4 x6 R2 P
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& S/ ]! V* I8 c% a* A4 C: {8 U0 a ;; initialize the global variables that hold patch agentsets
, @) U: R1 e+ j# g( Z- y6 ?, f set roads patches with' ?' `9 r- V1 l7 ^) }% b
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or8 o/ p( m) p/ Q! U* u; @5 K7 O$ S' m# g
(floor((pycor + max-pycor) mod grid-y-inc) = 0)] c& W0 n5 F* H) f9 U) K3 T P
set intersections roads with
( B+ T5 \( d6 Z; r7 B. [; e [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
3 x7 H3 g5 Z& [. t/ R5 f (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]3 k/ O2 \ A/ Y8 b! s# F
setup-intersections
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5 V* [! w; s0 m! l其中定义道路的句子,如下所示,是什么意思啊?
% C. B& [" W. y3 j; t set roads patches with
8 Y1 J( t- R5 R# w [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or3 W7 M6 @* o' F
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]- p6 k! X9 d" Z* X% R! D% O2 E
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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