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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。
* U* W) P' N$ P! D. y7 nnetlogo自带的social science--traffic grid这一例子当中,( g, [* h# @/ P- r5 E
globals
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5 E* F2 b4 i0 F grid-x-inc ;; the amount of patches in between two roads in the x direction1 j8 ~- n- N, r" N3 @8 t, V
grid-y-inc ;; the amount of patches in between two roads in the y direction
1 f; a! M4 W4 }. r) L. C3 n2 q acceleration ;; the constant that controls how much a car speeds up or slows down by if
+ F1 {: [# [: n/ e( q ;; it is to accelerate or decelerate2 z2 O! b' k! r" N9 T# c! `
phase ;; keeps track of the phase
# J! d/ w, J. D$ d3 i/ u num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
p5 l; m& m5 r# f: ?: y current-light ;; the currently selected light5 F8 ~/ S0 ` e% J9 r \2 a
0 M* D- y" ]0 V4 G ;; patch agentsets
* M2 Y, g8 s# `8 w intersections ;; agentset containing the patches that are intersections
0 Y( `; z- Y: T! N+ v. e* i/ T roads ;; agentset containing the patches that are roads. n7 r8 `9 e5 s m% C8 _5 f
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3 j3 r2 O6 W8 u/ zturtles-own7 }7 O$ Y% e; e7 A
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speed ;; the speed of the turtle
- T6 O" D( J% |; v3 A t, v# y up-car? ;; true if the turtle moves downwards and false if it moves to the right
* |% }3 @0 a7 \, B. R wait-time ;; the amount of time since the last time a turtle has moved
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# a& t6 y9 u* ^3 x& bpatches-own0 z+ }6 p- |$ w( d
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! b# e0 E S$ {' q intersection? ;; true if the patch is at the intersection of two roads
; J* Z1 [) D* @ green-light-up? ;; true if the green light is above the intersection. otherwise, false.: `* \( N6 ]$ y: L7 l) |
;; false for a non-intersection patches.
5 ]" z+ w% B5 y" a0 O my-row ;; the row of the intersection counting from the upper left corner of the
- l: O( L" a5 K$ v3 h ;; world. -1 for non-intersection patches.
3 p5 P9 Z1 f2 \( m my-column ;; the column of the intersection counting from the upper left corner of the, y+ r4 k( h4 ]1 U: d9 l
;; world. -1 for non-intersection patches.2 {; c: T3 A# g! \
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
7 {' J* j0 |1 Z& p4 d5 C auto? ;; whether or not this intersection will switch automatically.9 _! n+ A; t4 t8 I8 _$ \8 l
;; false for non-intersection patches. N5 X2 }7 @& ?# q
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;;;;;;;;;;;;;;;;;;;;;;
7 x# u* Q/ A" @4 x; J: w' `1 |% {;; Setup Procedures ;;2 W, X* ~& @0 I, O Q% |. V# K
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;; Initialize the display by giving the global and patch variables initial values.% [9 u& r1 S' X$ _
;; Create num-cars of turtles if there are enough road patches for one turtle to* u/ X( z- ]4 Y# L; E: M
;; be created per road patch. Set up the plots.
0 D7 t4 z q! @$ H6 V* K8 ~to setup
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setup-globals6 v! Q# ?( B2 |# y/ A
: r0 C/ N2 e0 x, X# x2 ~% ~ ;; First we ask the patches to draw themselves and set up a few variables
7 K* o& ^0 [6 F6 z9 W setup-patches
3 ?* o0 C+ n: \5 N* p. E# O+ v make-current one-of intersections
7 w" O6 N1 f4 f4 _+ D/ g S label-current7 L8 I) w8 t1 \. C4 P
1 {& l! K t5 M: Z$ T" Q: G set-default-shape turtles "car"$ o; G- }: b N$ r
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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 "$ Q/ [* t. G* F: v
"road. Either increase the amount of roads "
' q/ o( F2 _; \3 v "by increasing the GRID-SIZE-X or "
) Q! _: l! Z. E3 ?& @* b, D6 ~ "GRID-SIZE-Y sliders, or decrease the "$ b6 ?/ i. M# }# L- w% a) A
"number of cars by lowering the NUMBER slider.\n"
& y7 E8 p& N& _( d: @ "The setup has stopped.")' f" N. ~2 x, B
stop- S1 u+ W0 C- C I* l; W+ Z0 w
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color- w# N$ w& [3 Y2 U; d1 A* R7 }" k. N
crt num-cars4 Y( B8 F1 e# ^; y
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( D1 c4 W7 `+ E3 D% n) X" ]; A9 y- O, ] setup-cars$ d7 b) w. M1 d' q
set-car-color) K* D% c9 R' R
record-data) |* n# D9 V5 _1 B' Y# @& T0 W
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;; give the turtles an initial speed. p0 Z v" w. g' u3 {
ask turtles [ set-car-speed ]9 \5 j. ^4 D; t3 u! m9 ~3 f
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reset-ticks6 o' S; B7 ]/ i8 z, V
end9 f- I- H; m0 q, {6 t) ]
1 S# }: o# S7 ]% N' F3 F: H. b;; Initialize the global variables to appropriate values
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set current-light nobody ;; just for now, since there are no lights yet
( H4 l! n7 n8 K! |0 D4 F0 _ set phase 0
, c+ D6 @/ \- U$ b) T set num-cars-stopped 05 J" ]* H* X3 i/ R
set grid-x-inc world-width / grid-size-x
- X% |7 h7 j4 D$ S3 D2 M set grid-y-inc world-height / grid-size-y
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, W/ G- E- k, u ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary' Q1 K" V0 Y+ c! B/ N- O
set acceleration 0.099
8 ^% D% o" Q9 T2 N; f8 w6 Dend/ i8 U, ]- w" U3 x* p
+ l+ j O0 c/ l9 {. v5 R;; Make the patches have appropriate colors, set up the roads and intersections agentsets,2 O* u: f% Z0 K3 ]
;; and initialize the traffic lights to one setting* n* ^- S' d" p- g6 _% Z% T
to setup-patches9 l- s" e R* N$ u9 w
;; initialize the patch-owned variables and color the patches to a base-color
- \ b0 u9 }" r8 m5 Q2 A; c ask patches
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* a4 A7 r" v3 V- @' K, V set intersection? false l& J9 N* C- G/ ?+ z
set auto? false
4 T0 ?7 y% V. A3 v+ x4 S+ ]; O5 F set green-light-up? true
! o# V9 u" T4 s set my-row -1# y' M2 A( G. \/ e# m; ]9 ?" N
set my-column -1* |/ m5 T( l2 J: s8 [2 x. `
set my-phase -1
. S' ^% A: ~0 h, [6 O2 J( \4 X5 M set pcolor brown + 35 A& k1 ?5 N+ `7 u
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;; initialize the global variables that hold patch agentsets2 ?: Q1 a# F2 e& w s6 Y( x5 r
set roads patches with; Q8 G0 l) L' e5 J" T- t& @
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
8 z8 I& E" T' N: R (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
+ X# o5 X, w1 x; Z% X5 y- q set intersections roads with, M0 s0 r; X* W$ }
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
' Y6 p% a' ^6 z$ d' e4 s (floor((pycor + max-pycor) mod grid-y-inc) = 0)]* ~; n2 W: { B M
% i- V, j1 J# ^* ^ ask roads [ set pcolor white ]1 y6 X9 C1 m$ }& f
setup-intersections
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其中定义道路的句子,如下所示,是什么意思啊?
3 t& F5 q( U- u3 y! x set roads patches with9 |/ U4 p8 w5 r( ?9 b2 e
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
. `# z6 V7 `% r; C. D; ? (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
o3 _: n: q/ U, j2 u) |% j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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