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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。* r2 `3 l* q1 ~: X1 x* d
netlogo自带的social science--traffic grid这一例子当中,
6 k' u4 N+ j0 r: {/ D2 nglobals* ]7 f. L0 P0 i
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- d2 p: r/ G3 B+ p0 B8 S' G grid-x-inc ;; the amount of patches in between two roads in the x direction
' c4 b' V% v" O, U- R- T3 ^ grid-y-inc ;; the amount of patches in between two roads in the y direction9 d0 Z2 C! }- S0 q% u' [! G# C
acceleration ;; the constant that controls how much a car speeds up or slows down by if
" N( W/ A J- f8 l ;; it is to accelerate or decelerate
2 l9 _! ^7 s4 {+ M) g phase ;; keeps track of the phase9 P0 C4 M; h3 s2 R8 k, m
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure+ }( U: ^. p3 Z5 a
current-light ;; the currently selected light
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;; patch agentsets. _+ w8 V3 N# D3 k
intersections ;; agentset containing the patches that are intersections
1 s1 O, P2 C7 o3 b; ~ roads ;; agentset containing the patches that are roads
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turtles-own
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2 }# S' C) O% O6 H/ Y speed ;; the speed of the turtle% b9 p5 |& _+ t, u
up-car? ;; true if the turtle moves downwards and false if it moves to the right& |' C! _3 ?( w- Y
wait-time ;; the amount of time since the last time a turtle has moved# [. S% y0 K3 D$ u, P/ X
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patches-own& l1 ^4 m' O* I8 s
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intersection? ;; true if the patch is at the intersection of two roads9 l( [, y `" L& Q
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
9 r0 S# N5 Q+ a! U1 R ;; false for a non-intersection patches.
6 T k1 @" P+ O* Z& A) X) B2 Q my-row ;; the row of the intersection counting from the upper left corner of the
! Z5 i3 @- k( \, X: `, d2 z) I$ ]+ \ ;; world. -1 for non-intersection patches.
: j0 r }/ `( X' Q$ f my-column ;; the column of the intersection counting from the upper left corner of the1 r* D+ S: |0 X6 L7 b3 G
;; world. -1 for non-intersection patches.
+ J q0 \$ a" G) ]$ ~9 k my-phase ;; the phase for the intersection. -1 for non-intersection patches.! C: S+ l1 Y! H% q# j
auto? ;; whether or not this intersection will switch automatically.
& D V% a! p, I6 Q ;; false for non-intersection patches., \. |# k! a; G. L- T
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;;;;;;;;;;;;;;;;;;;;;;" `! Y0 g- ]4 \) O7 H8 I
;; Setup Procedures ;;
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;; Initialize the display by giving the global and patch variables initial values.
3 f1 G1 N# `5 @8 @;; Create num-cars of turtles if there are enough road patches for one turtle to
( q' e( K. p7 _1 Q8 H;; be created per road patch. Set up the plots.! A( R/ c6 ?6 F ~0 `4 S# o# n
to setup6 _+ G* V+ O8 k n
ca
: e( C, \+ U% @ setup-globals
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! U6 [2 p/ f; E+ R" ^3 E ;; First we ask the patches to draw themselves and set up a few variables1 h5 p! m$ n6 g; E& {+ p% A& j
setup-patches6 i4 _# J+ O0 f9 ^3 }4 q K
make-current one-of intersections! ]$ D7 I6 c5 V
label-current
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0 t' X; f/ [4 K2 w set-default-shape turtles "car"
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2 o m5 f+ q% b- F3 j. k1 c if (num-cars > count roads)& I2 f/ M( p0 `4 L" n& j# u# u9 U0 }
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user-message (word "There are too many cars for the amount of "7 {2 M, w% U/ k8 m+ S( a: M% g
"road. Either increase the amount of roads "9 ]: a! u" p: i" S4 `4 v
"by increasing the GRID-SIZE-X or "- U9 M) |* V' K& L) g+ ]
"GRID-SIZE-Y sliders, or decrease the "* V$ p# v! \' z# w
"number of cars by lowering the NUMBER slider.\n". x/ Y5 z- f e
"The setup has stopped.")
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3 i; u8 S- q0 X$ C( ?7 c1 f: @ ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color- j l& f* Q) W- S% F- I
crt num-cars
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% r U6 r; I/ Y& v n# o setup-cars9 a+ `, i! C- ^0 d! E
set-car-color
3 T: N, L7 D7 J( R record-data1 y. H0 Z( S1 ~# L
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;; give the turtles an initial speed: L- m7 p; n, V* M3 ]
ask turtles [ set-car-speed ]
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reset-ticks
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;; Initialize the global variables to appropriate values0 p, ^' T, M1 l- X- P+ ^
to setup-globals0 _2 d i7 g+ {
set current-light nobody ;; just for now, since there are no lights yet
" }7 w; z# N: s9 U3 t set phase 0( y. Q2 a$ {+ P7 ^5 K
set num-cars-stopped 0# \4 r5 ~3 D {) \" t0 v9 b( k& m9 V4 }
set grid-x-inc world-width / grid-size-x' n/ J- s! r, P
set grid-y-inc world-height / grid-size-y& R Z* T4 c4 `6 f- m1 p
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary: x s) R: Y A9 x' f- s5 f5 M( s! k, s
set acceleration 0.099( Q1 l4 J" t& y A: D0 N
end/ I6 F; K/ F$ R; G+ Y7 ?8 Y3 a
. P" \% r* `- j# d;; Make the patches have appropriate colors, set up the roads and intersections agentsets,3 k# z3 ]3 ^$ }" w
;; and initialize the traffic lights to one setting8 {9 y, E* l7 o, O6 a2 @9 Q7 @
to setup-patches- u9 V3 N4 p# Y x* a6 j% }
;; initialize the patch-owned variables and color the patches to a base-color; `4 Z" r6 b$ C3 R) R$ @5 ^' {$ j# G
ask patches7 b. ^' T, n u4 P l& U" f5 z
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9 a* R, X8 u7 v& j& W set intersection? false
1 j1 ^# O" T5 W: [, t( N set auto? false
7 t8 C! ~8 y7 x1 C+ X* r set green-light-up? true! G r6 F2 X2 L; C# F
set my-row -1
a1 i! @# v. {8 i set my-column -1
; c4 w# j; I& u2 U) _" r set my-phase -10 y9 P2 \, q$ y& p& {
set pcolor brown + 3 F9 F8 H; y+ P; r' n* \: X
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. t9 E2 }4 h% Q& p0 _) X' d( s ;; initialize the global variables that hold patch agentsets
9 B3 b2 P; s* ^ @ G6 Q set roads patches with
$ o+ b) I6 X/ Y# e2 a1 c" t, S9 h [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or) E: `: R) D+ t: R, A9 H. W
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
! E0 _& ^, Y1 `" ^% G set intersections roads with
4 [ F4 ~# d$ T- V& c8 D [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and1 M9 y- B6 k8 n0 t: {6 z0 j' f
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]" W: p; C) n3 G# b
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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?2 l0 G1 G( [$ l* h! r& h
set roads patches with
- Y. n+ J+ X* P6 L4 j2 {1 Y! A% @ [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
/ n/ n2 S2 [) v: n) W (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
: A) X0 S2 W- r4 a1 R; o' P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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