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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。, _5 F; S2 n9 ]0 Z; f
netlogo自带的social science--traffic grid这一例子当中,
( J& V5 x6 I# u% kglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction8 k, Q% R9 ~1 _2 v7 u# G7 {
grid-y-inc ;; the amount of patches in between two roads in the y direction' A r7 y. c' K+ @/ ]5 O
acceleration ;; the constant that controls how much a car speeds up or slows down by if
; o1 C9 ]) t8 b$ W. f8 k ;; it is to accelerate or decelerate" F+ C- o- G6 m5 s0 k. q% t3 E9 _5 w
phase ;; keeps track of the phase! T+ [ ~0 N( O0 ]& `$ X# z
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure4 x. a3 M& t/ y- G, T' L$ {1 v
current-light ;; the currently selected light
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% j8 I' t+ s. J; N# d4 @* y6 P ;; patch agentsets
: Z7 @$ o# Y, \+ D& [# U- v intersections ;; agentset containing the patches that are intersections
2 h' s3 R) ?* p# N! s roads ;; agentset containing the patches that are roads
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turtles-own, }" z& S1 G+ `' ^( ^9 J
[
H1 H* M/ M, \) q: s+ B& x speed ;; the speed of the turtle1 j9 w4 ~, k' c
up-car? ;; true if the turtle moves downwards and false if it moves to the right
7 X& R1 i- E) L3 c8 N, Y" O wait-time ;; the amount of time since the last time a turtle has moved7 g% Y7 h& \2 F% t" o& N
]
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( A0 J6 u" j2 B. f E+ gpatches-own7 s9 T/ h5 o' ^0 G4 F8 w: z
[
( W) D: r/ i8 k7 S3 P& a$ |) a intersection? ;; true if the patch is at the intersection of two roads3 P* b* V3 a% [' `% ^
green-light-up? ;; true if the green light is above the intersection. otherwise, false.2 c- v* X. ^1 [
;; false for a non-intersection patches.
7 n. ~& \ T$ N8 n8 U# { my-row ;; the row of the intersection counting from the upper left corner of the
' m8 }' }# x+ [* t9 } ;; world. -1 for non-intersection patches.
) A( E, b7 H/ c1 u2 \ my-column ;; the column of the intersection counting from the upper left corner of the
, N) `' V/ W- W2 u; W& u& R% h* K ;; world. -1 for non-intersection patches.
! C7 H/ X; M" W$ | my-phase ;; the phase for the intersection. -1 for non-intersection patches.1 |3 D' i% h, e \. R3 z W
auto? ;; whether or not this intersection will switch automatically.
4 \4 J2 r5 S4 e% Y. O ;; false for non-intersection patches.: @% V' N1 E) x6 C5 b3 I( D
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" R8 ~2 m ?& c, l; [% q;;;;;;;;;;;;;;;;;;;;;;
& W; U" M( \2 W$ y1 a0 m. Q' L! ?;; Setup Procedures ;;
0 b1 e3 s1 v7 Q3 u) D) m% w;;;;;;;;;;;;;;;;;;;;;;8 v) {5 r; r" C
* J7 Y6 e) s" |8 X7 b;; Initialize the display by giving the global and patch variables initial values./ K3 R2 O( E3 G' Z* V
;; Create num-cars of turtles if there are enough road patches for one turtle to
* Y! n& u+ g: k# N5 n;; be created per road patch. Set up the plots.
0 j5 n t- v3 W" h" nto setup* E: b, ~# E( B$ o5 H
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setup-globals
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3 p$ H1 n" @, V& f ;; First we ask the patches to draw themselves and set up a few variables: A7 ?! y7 r o/ T8 C0 I. {! g7 R
setup-patches
+ P( {3 }6 _5 T% |% Y( ^0 } n make-current one-of intersections
+ w+ B; U- c1 D, \5 E label-current8 B- }) B. i6 i% h2 G) k; J' H
. q. C# m9 r. Y; |# w: g3 d, ^% K set-default-shape turtles "car"* k$ Y- N& k5 v3 j9 `9 n
+ A; n5 J% f8 y+ L2 f! u: T if (num-cars > count roads): m3 y3 M2 g0 x; z& i6 i6 E
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user-message (word "There are too many cars for the amount of "
/ ]- i& d7 k$ w& B( J. u/ g "road. Either increase the amount of roads "6 E! F3 b. J% N- G# l7 _& H
"by increasing the GRID-SIZE-X or "
- w3 x7 O% N8 E' ~! N" F "GRID-SIZE-Y sliders, or decrease the "8 H3 ?' D4 t2 F) Z5 o) @
"number of cars by lowering the NUMBER slider.\n"# V) x0 V6 K+ q7 M# A2 J& j0 t. m
"The setup has stopped.")
" [8 Q* g( Y, p% `+ ~ stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
2 w8 Q2 l# U8 T7 C crt num-cars' t3 T: Q8 e t- c
[
9 s, e# m" ]& w! _8 l setup-cars' O2 N& t/ \. k* R6 t
set-car-color% d% t v! M( D% O/ g, @; f P- e1 P
record-data% k1 D5 c) w( k5 |# _
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;; give the turtles an initial speed) R; I8 L5 \# g, l# D z1 z
ask turtles [ set-car-speed ]( E5 b w0 Q9 V* t
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reset-ticks* Q" b# B! P; d, ^$ D
end
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;; Initialize the global variables to appropriate values
/ h, j1 } _. N+ T" E& Zto setup-globals! e' ]: y# b6 q
set current-light nobody ;; just for now, since there are no lights yet3 f: p$ f) W# Y/ k! B) s) l3 d6 \& o
set phase 05 Q1 X* {$ t5 h/ y& h5 S$ F: ?
set num-cars-stopped 0- J2 }0 m5 B# [
set grid-x-inc world-width / grid-size-x
5 }+ P8 P4 U3 ~5 h4 R5 { set grid-y-inc world-height / grid-size-y
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. ^% V/ d9 G9 c ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary; A4 ?/ b) i( }
set acceleration 0.099
! `9 g4 N; E9 @5 ]end5 A) I# F0 T3 ~7 j
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,5 b/ y. k, u0 C9 k* e z8 `
;; and initialize the traffic lights to one setting$ j, J" G& W7 n* `; B5 Z; G9 t, P
to setup-patches7 g. N; V* Z5 I6 r3 y3 k; d. h# S
;; initialize the patch-owned variables and color the patches to a base-color& {+ }9 [8 D3 C6 [2 M" q- V
ask patches
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set intersection? false+ ?! i3 z; G( P) v
set auto? false K; {, L. l( j2 f
set green-light-up? true
6 D8 v# G$ v# j$ v set my-row -18 @" |+ @3 ]! V9 R
set my-column -1
3 `1 c/ `/ k, O; v* e$ B7 l set my-phase -1& R5 x8 v, M" f: v
set pcolor brown + 37 q/ `: m. m) \, B
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+ M- x M9 f9 h; j8 I, j% M ;; initialize the global variables that hold patch agentsets
+ m& Y' V6 u8 U+ _, |' z set roads patches with
2 G0 B9 v+ `5 J# A& m. [. P" r( A) I( T [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or) o4 W3 w' o8 \4 F2 f/ c/ g ?
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]4 x- r- H0 E# w8 @
set intersections roads with B) L' g! O/ j# T. f0 B
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and* B0 F9 p. S' B8 W
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]# S3 H9 T y v# |) |6 @) q
. l8 r( X$ G- c' k ask roads [ set pcolor white ]# ?$ E/ ^7 ~( g9 l( \- v4 e* B
setup-intersections6 z' }; l' ~. k" b
end+ T* k2 z# p3 Z, g# O+ E
其中定义道路的句子,如下所示,是什么意思啊?
; p7 D a9 F2 d3 R0 H7 K" M set roads patches with. T/ p# b" f% a, F
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or, C3 d7 D: Z& }& a
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
: u. F9 {- x7 {5 D! [0 [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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