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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。* V8 Q: D# o4 E1 L3 b A0 O% ?
netlogo自带的social science--traffic grid这一例子当中,
' Z. h% X: s+ O- Fglobals+ K" O0 ?; w3 i+ K G7 w
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grid-x-inc ;; the amount of patches in between two roads in the x direction# w% `& K, s/ \* K& z7 {. @
grid-y-inc ;; the amount of patches in between two roads in the y direction
, t7 f |, U7 d acceleration ;; the constant that controls how much a car speeds up or slows down by if
) J) z& B* J. z! A( g8 _ ;; it is to accelerate or decelerate
$ v$ ^# z1 u' z- R' |- g phase ;; keeps track of the phase
) {/ k: O2 X7 Y; U num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure$ |/ ~7 l2 l2 \* p4 o
current-light ;; the currently selected light8 L/ [* W0 i! ~2 p
" ?+ [4 _3 g. R! w ;; patch agentsets
2 q! i" |5 N% v! N intersections ;; agentset containing the patches that are intersections
1 w9 u. O' v( |1 S6 F8 h: e roads ;; agentset containing the patches that are roads
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turtles-own
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speed ;; the speed of the turtle
1 X# M; N3 [& _4 A$ m. R0 a$ F up-car? ;; true if the turtle moves downwards and false if it moves to the right
; y9 v9 [& m- B/ S0 K wait-time ;; the amount of time since the last time a turtle has moved
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: D% V2 ?8 s u0 _patches-own
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1 r& |' k$ x" j2 v) D intersection? ;; true if the patch is at the intersection of two roads
7 a. j5 o) W0 F( C green-light-up? ;; true if the green light is above the intersection. otherwise, false.
, n8 o5 a: r' w4 h& l ;; false for a non-intersection patches.; F) \: q! X8 f- j
my-row ;; the row of the intersection counting from the upper left corner of the
6 l: @3 @; ?- v5 t9 d) I1 W ;; world. -1 for non-intersection patches.5 i% a; \- y/ G- s3 Q) d1 u
my-column ;; the column of the intersection counting from the upper left corner of the. `0 p2 O' Q* e/ z) L2 Q# m
;; world. -1 for non-intersection patches. G8 Q: l7 @9 F% ?7 s2 j$ ?8 r
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
r( u; E" m; e4 g+ }2 M auto? ;; whether or not this intersection will switch automatically.& Z s2 |: b& D! u
;; false for non-intersection patches./ ?8 D7 }2 P% `: a* c
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4 j# ]; w4 z( k9 ~9 G;;;;;;;;;;;;;;;;;;;;;;- i) o8 d# A4 n1 z4 R8 x
;; Setup Procedures ;;4 E9 _+ u3 w7 U- b: z! A" l7 } [" f; p
;;;;;;;;;;;;;;;;;;;;;;
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$ z4 y s& K1 O) D; u! t;; Initialize the display by giving the global and patch variables initial values.
, ~1 N% V0 i6 C+ }1 ] e;; Create num-cars of turtles if there are enough road patches for one turtle to
# g4 ~- o+ s. z& n;; be created per road patch. Set up the plots.
& z$ Y' |5 Z' C5 W6 Wto 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& J: v9 o9 r& n5 K% Z: a% h1 ~
setup-patches
4 u% h2 B! }/ r6 h+ N make-current one-of intersections+ \" ~5 Q4 K5 F+ Q! p
label-current
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z$ ~* m9 r8 [5 |& ?9 R" S Q set-default-shape turtles "car"
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if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of ". A) P' L0 `: y$ V c8 e; E0 x
"road. Either increase the amount of roads "3 W* V5 c! S) u# _
"by increasing the GRID-SIZE-X or "
) w' g) i: f+ w- R. u+ _6 Z "GRID-SIZE-Y sliders, or decrease the "
8 S/ @& c3 ^1 @0 s "number of cars by lowering the NUMBER slider.\n"
7 s0 P1 H2 t+ L# u, r! j+ S "The setup has stopped.")
4 p" c. Q7 B# B. a8 n) { stop
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/ s6 G$ j" I' o* \4 g+ s ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color6 b! g& A h7 ~ H
crt num-cars$ i ~9 t# k9 N; s# A8 h
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% z, {$ [& N6 \6 |' X, m) s setup-cars! Z( |' x2 Y f3 x0 Q4 P* q
set-car-color% @" v: s' s9 Z# q$ g
record-data
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$ p- l( b8 ?5 `7 ?' Q( w* e7 h ;; give the turtles an initial speed
5 J. b! J; g8 [- C ask turtles [ set-car-speed ]% J7 e v1 V z# @
* l% ]8 c5 z; c2 y reset-ticks
6 P( H* e7 X: s( N" s% yend
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;; Initialize the global variables to appropriate values
9 f# e3 B$ |! N3 hto setup-globals
6 x. n( {3 Z, d set current-light nobody ;; just for now, since there are no lights yet& a) N' _$ N' o# A% ?
set phase 0
3 g- b, N0 k3 C7 ? w6 i set num-cars-stopped 08 _$ p. B/ R% B- f
set grid-x-inc world-width / grid-size-x q; e% F9 @& x5 o5 H: o
set grid-y-inc world-height / grid-size-y$ D4 |) F$ N+ p6 T
! y/ A5 B5 Z a" @ V+ B ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary/ u9 Q0 Q4 v" @' ]
set acceleration 0.099
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,8 y0 x) i5 V3 _4 j% B H2 J8 J
;; and initialize the traffic lights to one setting; I9 R, g/ {# R* c2 B- P: h* X5 X
to setup-patches
- c$ O# m2 ^$ z) G0 r+ P ;; initialize the patch-owned variables and color the patches to a base-color
( g' ^0 Y5 I1 p; K2 } ask patches ~5 j- b" r* w; \# p7 D
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set intersection? false2 b N% i: D- ^3 R/ k* b4 |
set auto? false
0 b6 [% O; E# ` set green-light-up? true
% z. x9 Q( o9 U1 M$ H7 J1 {/ ?5 Q D set my-row -1
8 b \0 | f; h s+ I0 B set my-column -14 K: Q$ `- X# G1 Q
set my-phase -18 t% p9 R$ C5 G! V, @" ~
set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets& g7 s4 m9 H4 g) I( C
set roads patches with
: X6 g: Q+ _' T% C/ C5 x [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or" B% E1 Z" n# n% u7 j
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]2 |* P7 n, ?$ k% n; N. N, r
set intersections roads with
$ d6 R$ F/ q# ^2 }* w [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and* j1 g& T5 C V# B7 g. U3 g7 ]9 y! }
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]0 }9 D3 m( ]8 j' a8 |1 b h; c! a
. l" i, R& x" q# S; r$ C1 d ask roads [ set pcolor white ]
& X) W! j- T8 ^, A setup-intersections9 p( n1 p! Y0 T* E
end4 k& x, \% e& H) T) i8 ~
其中定义道路的句子,如下所示,是什么意思啊?) Q1 a7 z% V7 H3 a
set roads patches with& s. l9 L! x( j5 U+ `; B
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or- c9 H1 z- B+ Q/ K; v8 E# q
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]* c5 N# Z2 e1 \/ ?! Z9 l
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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