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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。
* O" a, ~; L' y- G: X9 y ~netlogo自带的social science--traffic grid这一例子当中,
/ @: |: |; Y# D- |) Nglobals8 e" r2 q* S, I* H r, `
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+ P3 x& q3 W8 k- _ grid-x-inc ;; the amount of patches in between two roads in the x direction$ ?4 G4 A2 j. R0 @/ k9 s. I5 [6 M8 t
grid-y-inc ;; the amount of patches in between two roads in the y direction
. ]0 }1 v4 C- t0 o- o' ?; ? acceleration ;; the constant that controls how much a car speeds up or slows down by if7 A) j4 J7 }8 e. C
;; it is to accelerate or decelerate2 e$ w7 {' [: F9 S! @
phase ;; keeps track of the phase% P6 H! l a7 F! p! Q) T7 z
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure: ]! e* Q; c# m8 T
current-light ;; the currently selected light
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1 s& r. v8 x5 f( _* A+ b: k, ^7 F ;; patch agentsets. G6 Z7 I& T$ o: D9 t! _( x
intersections ;; agentset containing the patches that are intersections
3 T+ m" p8 y; b( 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
) G) w: b5 I8 B H3 k0 L up-car? ;; true if the turtle moves downwards and false if it moves to the right
4 Q1 L2 R, D: {5 ~1 m b wait-time ;; the amount of time since the last time a turtle has moved
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patches-own8 r1 o. P6 ^+ C! z
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intersection? ;; true if the patch is at the intersection of two roads3 \, N( i1 H n& F
green-light-up? ;; true if the green light is above the intersection. otherwise, false.8 c% i& r1 ?6 J, D. r9 j8 F
;; false for a non-intersection patches.0 Z |5 m& {$ J$ N
my-row ;; the row of the intersection counting from the upper left corner of the+ w# J$ ~5 R# ?
;; world. -1 for non-intersection patches." }" U$ w. l" ?* R R- _" \! }
my-column ;; the column of the intersection counting from the upper left corner of the
! \- l8 ^& e7 S ;; world. -1 for non-intersection patches.+ P$ I+ k8 p" ~
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
* n" b: X) b# B' }/ D* @( g3 M7 ? auto? ;; whether or not this intersection will switch automatically.
}2 g% O0 T/ U ;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;
$ d1 p' y9 _1 G5 c7 }8 E7 u+ r;; Setup Procedures ;;5 o5 k* |7 A o" z- d; v- k
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1 ^& @; Z5 y. P) o1 p;; Initialize the display by giving the global and patch variables initial values.
$ O& M7 H% v& Z; p4 h9 {- h" |;; Create num-cars of turtles if there are enough road patches for one turtle to
% S, L: J7 Q6 A6 ^;; be created per road patch. Set up the plots.$ x7 F" c K4 e! x5 {! W( a
to setup
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5 P9 K1 D; R6 d9 e. z8 ? A setup-globals5 P0 N2 X. i: ]
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;; First we ask the patches to draw themselves and set up a few variables; a: u$ O1 g5 @5 ~$ w: g- s+ S( }: S
setup-patches' }$ L7 Z- h% q
make-current one-of intersections# z; m ]- L6 Z9 r" N3 Y
label-current
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! Y7 e0 J# S+ b/ J) K1 r7 \$ T4 L set-default-shape turtles "car"
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if (num-cars > count roads)9 E3 X' k# s" G' ?6 c
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user-message (word "There are too many cars for the amount of "
: R9 J0 L/ C$ i# d1 {0 p) @ "road. Either increase the amount of roads "8 W, ~ M+ ~+ a
"by increasing the GRID-SIZE-X or "; z: N0 L2 |) X8 E6 W' d
"GRID-SIZE-Y sliders, or decrease the "
+ ]: g9 \# F& D( A1 n, Q% W3 V+ } "number of cars by lowering the NUMBER slider.\n"
1 H! h2 P1 Q* P6 w4 c# b "The setup has stopped.")3 P; t8 C9 C( L* ]3 m' Z5 r
stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
' c" u) x' `( F- z crt num-cars
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setup-cars
$ r+ W3 e0 R! F set-car-color/ F5 G" i: _7 p% M. |) S" B
record-data
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;; give the turtles an initial speed4 k7 o* y K1 |2 T0 d5 ?( Q
ask turtles [ set-car-speed ]: W0 M/ H+ h) D$ X7 W3 l
# I' A; r N: ?1 J4 ?+ W reset-ticks% H( n% v6 c5 l6 G$ A) u7 g4 e0 R* u
end8 h; H8 g5 C- T; G
% |4 s/ ]. @5 `0 {/ K- K;; Initialize the global variables to appropriate values
( T8 c8 i. K& Z0 i& Kto setup-globals# z' o! Q2 B' q. i; Q
set current-light nobody ;; just for now, since there are no lights yet/ R* ]# ^+ p% j' D
set phase 0! t1 ^/ f4 Z5 a7 p$ {
set num-cars-stopped 0- R# d% K, R) ?3 k
set grid-x-inc world-width / grid-size-x0 _& M1 ]- I0 F
set grid-y-inc world-height / grid-size-y
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
3 v# Q v- i# r1 B set acceleration 0.099
- A# z3 r" D6 ~$ K* `8 n: oend
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
& F, }2 _" R6 p: i' d" [8 M* r! N;; and initialize the traffic lights to one setting
+ G; u4 i6 n5 Z: m. u3 wto setup-patches
: q4 @8 }4 i( K+ C4 `' J8 \( V ;; initialize the patch-owned variables and color the patches to a base-color$ }, t% Y, ?- Y# y
ask patches
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2 l. ^* j# e5 ^( W- Y set intersection? false
5 P: Z3 s1 D. | set auto? false
+ n) r; T. ?6 e7 z7 A- q2 j set green-light-up? true! b P1 e. C3 X
set my-row -18 F2 Q l* N7 O4 ^5 K" A! W+ E
set my-column -1) Y7 R; ] B- ]
set my-phase -1
Q: U$ w2 ?: E% _$ D8 { set pcolor brown + 35 s+ C3 @. ]: p) i3 L% g) R4 B8 k
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;; initialize the global variables that hold patch agentsets
. ^2 {3 `6 b( Q; L/ {& d& I set roads patches with
F) W( k4 r- [. W1 t& b- H [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
: @; p; S M* Y" {$ L (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
' z; l4 P& Q* a0 Q set intersections roads with
1 Z/ Z# Z1 o8 k# U6 A. Q [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
) H# B- ^- z" u( u9 b! k (floor((pycor + max-pycor) mod grid-y-inc) = 0)]- F2 g/ q( F- Z3 Q' q
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ask roads [ set pcolor white ]! _, l$ \2 K1 r/ ]* K
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?
8 n& R. i& B) c( Y set roads patches with
9 F6 T- Z* U0 P5 r [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or: ~% O2 p& \4 y5 d* J: p5 p; J8 ^. O
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
4 p% |, C% f D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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