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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。9 \6 t% Q7 ?# c5 e' {, X
netlogo自带的social science--traffic grid这一例子当中,
/ a) \* H, r& U9 H$ r7 e# p6 O) Dglobals: m( T+ R2 I8 c O3 _
[6 {* S- U$ s# i5 s5 ]- x
grid-x-inc ;; the amount of patches in between two roads in the x direction6 u8 n% r) J% X2 g! e
grid-y-inc ;; the amount of patches in between two roads in the y direction" Y( J0 D% I9 M: W
acceleration ;; the constant that controls how much a car speeds up or slows down by if" D) E P# J$ A# R- ]
;; it is to accelerate or decelerate1 W8 B& R. u2 y0 E: D
phase ;; keeps track of the phase$ p$ [" t, p) \4 I# T+ l
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
0 G( e( e _5 n, R! M, U# a6 ~* q# w' b current-light ;; the currently selected light( e* @) O; z9 H$ g7 z8 m; u9 v
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;; patch agentsets
3 i# j( k1 z4 m; h% m intersections ;; agentset containing the patches that are intersections
; }8 [5 s) A8 q5 `$ M roads ;; agentset containing the patches that are roads7 w" c! K: `4 N
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turtles-own
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speed ;; the speed of the turtle0 ], Y! Q% G3 d& m: g
up-car? ;; true if the turtle moves downwards and false if it moves to the right. U3 l' L, F6 ]# h g7 g( e- ]
wait-time ;; the amount of time since the last time a turtle has moved
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads4 G* ]$ V9 ~0 N7 a- d
green-light-up? ;; true if the green light is above the intersection. otherwise, false.2 c3 A+ s; ?5 f1 A# X
;; false for a non-intersection patches.& v$ n3 v6 G4 X6 F, S5 V6 Q4 n
my-row ;; the row of the intersection counting from the upper left corner of the
; T+ P7 P( X m. A# r( w ;; world. -1 for non-intersection patches.2 Q9 Y! U" U# m& s% t4 _
my-column ;; the column of the intersection counting from the upper left corner of the- U& t* a* E% H$ N9 T1 r1 N
;; world. -1 for non-intersection patches.4 y4 \% V3 ?( f& l5 l3 S. k
my-phase ;; the phase for the intersection. -1 for non-intersection patches.- J; _% r8 |* {6 l9 y# ]4 Y
auto? ;; whether or not this intersection will switch automatically.
0 \: E4 @" X* U ;; false for non-intersection patches.- r) k, x; g' V3 @3 x- a
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;;;;;;;;;;;;;;;;;;;;;;8 C; W( ^' a, C1 @& i
;; Setup Procedures ;;
0 D1 ^" @( |$ M" v' e;;;;;;;;;;;;;;;;;;;;;;" C* o0 d' w% X
R& j; Z, r' q;; Initialize the display by giving the global and patch variables initial values.
) V8 k7 x& k" j0 h;; Create num-cars of turtles if there are enough road patches for one turtle to
' `/ M9 z* I( {2 A% H6 }, k- J. ?;; be created per road patch. Set up the plots.
3 G- S8 T( Q) t1 }, ]( d) xto setup
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setup-globals
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;; First we ask the patches to draw themselves and set up a few variables0 ?4 M9 g* r J- o" k
setup-patches) Z% ]$ z8 r/ s
make-current one-of intersections
" }( b: @. Z s8 @- b4 Z8 C8 M label-current! c4 u: Q% d% B) V; x
7 i2 D; c1 ]% C' O: A+ f set-default-shape turtles "car"6 t8 G& F6 W4 l- A
: g; {) @% v3 h8 h, J if (num-cars > count roads)" G; m p2 C3 y+ Z8 q
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user-message (word "There are too many cars for the amount of "
# e6 o. b& `) \/ d7 L "road. Either increase the amount of roads "
1 R2 [/ B, S1 a4 d. W, j9 I "by increasing the GRID-SIZE-X or "
% p) f9 F0 M8 B8 x- V "GRID-SIZE-Y sliders, or decrease the ", A; I/ G; {. n b7 Q$ ?5 N7 W
"number of cars by lowering the NUMBER slider.\n"; S2 |, e5 Z4 I% i! N8 t
"The setup has stopped.")3 K9 [/ | f# @2 Z/ o f( z$ _
stop6 M; Z g, y \
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2 G9 O9 x5 k( d1 R$ B9 ~ ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color2 S8 H: w# K( A P/ m
crt num-cars
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setup-cars% U# Q; E; i: g8 e2 g* `( l
set-car-color
& i/ Y6 Q( r' d record-data
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9 I" Q" f" y* m' V# f5 A3 [ ;; give the turtles an initial speed" t9 C8 b# U0 j5 h
ask turtles [ set-car-speed ]) S8 F8 l! i+ i+ G
- E/ L( l+ L& a, D& b reset-ticks* B( |2 m ^" H
end: K- T+ [, S2 E7 n9 z+ w# {
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;; Initialize the global variables to appropriate values1 _0 @5 T* K: @: }* j
to setup-globals+ s( \/ U- }2 B p3 C; k
set current-light nobody ;; just for now, since there are no lights yet
' y) a3 y1 {% ]6 A# F- ` set phase 0
. g1 ^% X! Z3 V; ^9 R) F9 X set num-cars-stopped 0
; C( t7 z' ^! U set grid-x-inc world-width / grid-size-x
) f! O5 S6 h1 f) P! k6 l3 C9 X set grid-y-inc world-height / grid-size-y
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, u3 n* Z6 o: U8 j Y7 b ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary) ^, y# l& c2 c* i% W
set acceleration 0.099
& l" d. y& s3 H9 ?3 ^' ~end' `; w, t* V' r$ ~- U% C+ a; n
( u7 R0 ^1 W* K$ R;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
* t8 T- @3 @' v A;; and initialize the traffic lights to one setting
6 ^$ ]7 ?( a0 ^% \7 u0 K0 gto setup-patches4 Q, H1 I( C, q8 y
;; initialize the patch-owned variables and color the patches to a base-color7 W9 [; O9 r% k/ M
ask patches$ {! O5 S# E1 t0 B! p! ?1 U
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" R _2 q/ d/ g X9 C, J4 r set intersection? false
+ s# Z+ A8 I3 B! p. Y9 L j set auto? false
5 |) |' N) s6 K( @* Z* ~6 _ set green-light-up? true$ k3 D y, a8 E* h7 D* w
set my-row -1; j2 w$ s0 a- b: g" Y. S5 I% E
set my-column -1
3 d' [( Z# I: U; n. F set my-phase -1* T3 u' B9 [0 M# W9 ?
set pcolor brown + 39 z% P0 A" Y! R. [1 O7 R3 G A# c0 m
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;; initialize the global variables that hold patch agentsets
+ u6 G6 i, R" R2 U& a+ H set roads patches with
5 q/ H, K: F; X( t4 a' o# q [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or% D4 N" X5 l5 X2 ^
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]; ^' b% X" r1 u, s' s
set intersections roads with
7 j! J9 D9 o6 J, n- l7 P [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
# N" R2 g! e4 f4 H3 C, @2 K (floor((pycor + max-pycor) mod grid-y-inc) = 0)]/ }4 ^( b w& V) n
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ask roads [ set pcolor white ]
& q4 H" ^# u; m/ o8 m& {8 L setup-intersections9 m# G2 z$ Q( N
end
4 W1 W$ t- j0 S* u* ^8 f7 W其中定义道路的句子,如下所示,是什么意思啊?
! N' i1 F' X! v, G' B) l set roads patches with( b- G) a4 F" S
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or# Z; S5 e) _; r0 ~! Y% R) g6 t. h
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
$ z' z) _1 a& [0 n% H6 Q, S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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