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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。- R) a: _/ j+ X3 I. f! _
netlogo自带的social science--traffic grid这一例子当中,
- ^) N' @- q% X. Iglobals( i1 o" V; [, P& m: v
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grid-x-inc ;; the amount of patches in between two roads in the x direction* W R. l6 h- q( A: O7 S7 L
grid-y-inc ;; the amount of patches in between two roads in the y direction
2 r: q0 S9 m- R: S5 \8 j, c acceleration ;; the constant that controls how much a car speeds up or slows down by if* W ? s4 k: w" Z2 ]5 R$ F. ^
;; it is to accelerate or decelerate
8 p3 J# v1 z7 ~" E5 d' G6 J phase ;; keeps track of the phase
# \ s' w: U) m8 A4 q' h num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure5 W2 Q1 _8 b" N+ U. b" a/ W; |
current-light ;; the currently selected light
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9 f% O" F) w/ V: X% Z ;; patch agentsets( T: |# j* i6 m9 e* H& H7 j
intersections ;; agentset containing the patches that are intersections
" g; ~( o( W$ l2 v( ^2 Z6 O; X roads ;; agentset containing the patches that are roads6 [1 g. B1 _# m; M% Y9 Y
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turtles-own
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" ?3 r. M1 s1 a) I speed ;; the speed of the turtle4 d' W$ D$ V9 @& H9 d- c9 y
up-car? ;; true if the turtle moves downwards and false if it moves to the right
+ S/ S4 q( P: a0 {* ~4 L wait-time ;; the amount of time since the last time a turtle has moved
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patches-own- A1 P2 c. x5 T' p" p
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intersection? ;; true if the patch is at the intersection of two roads0 j. G+ k5 H8 n+ e7 d& w( @
green-light-up? ;; true if the green light is above the intersection. otherwise, false.5 P, m+ J3 Z5 O& S
;; false for a non-intersection patches.
. r# v. r- _' R4 q4 _ my-row ;; the row of the intersection counting from the upper left corner of the
/ g D2 ?2 n7 E# S ;; world. -1 for non-intersection patches.
8 M2 H$ w: R+ N* h7 k* q6 Q2 k my-column ;; the column of the intersection counting from the upper left corner of the6 {0 b( @# g% Y8 ]) P
;; world. -1 for non-intersection patches.
, B4 D0 V+ a/ j9 }8 x* [# a1 v my-phase ;; the phase for the intersection. -1 for non-intersection patches.
$ o9 ^' v' d4 B2 B( E& @* g auto? ;; whether or not this intersection will switch automatically.
% W; I4 d0 V6 n ;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;
: O3 [& e/ p" S;; Setup Procedures ;;9 \! s) n, O0 n! u) f
;;;;;;;;;;;;;;;;;;;;;;
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~# c* I6 F) R; q3 a: |;; Initialize the display by giving the global and patch variables initial values.7 @% X4 ^: e% e! @7 B
;; Create num-cars of turtles if there are enough road patches for one turtle to$ a+ S- N5 z$ H( L5 O" A4 |; K) w# r: ^
;; be created per road patch. Set up the plots.
$ } W+ G5 D5 o% E. d, Zto setup( h. ~# E/ u$ |2 W9 _# @8 [* a' X. R
ca
4 P3 ^3 k" K7 E setup-globals8 U- N0 B* F5 E+ U
) \7 k; w2 [8 O ;; First we ask the patches to draw themselves and set up a few variables
6 w4 R7 S+ p5 [* J setup-patches
1 b" m# @" ^* U" |4 N make-current one-of intersections
9 }0 J- d$ I6 D4 e( W! s& D label-current
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2 K q i, M: m" { set-default-shape turtles "car"
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if (num-cars > count roads)
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/ I* G/ l0 |1 m user-message (word "There are too many cars for the amount of "/ s& s* L) Q1 g3 W6 |+ O# s
"road. Either increase the amount of roads "; h/ P3 j* `: e0 Z
"by increasing the GRID-SIZE-X or "
2 q7 {2 a! x' E$ _5 n8 n( N' F "GRID-SIZE-Y sliders, or decrease the " g9 i- W+ y5 y+ d; V8 J
"number of cars by lowering the NUMBER slider.\n"! t, z) m3 W, z4 R- Z# J( a
"The setup has stopped.")9 J; q3 c+ ^3 Z9 B+ t" r. [7 h! l6 N+ ~
stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color& p" X* l C& @2 w
crt num-cars
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setup-cars! K1 d3 A, r, h( r
set-car-color
& y3 I) v% i' ]# e9 L$ O* s! i7 W record-data. Z- C1 O- t/ a/ e u
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;; give the turtles an initial speed& X. s* U5 _2 B* L! q6 _
ask turtles [ set-car-speed ]! f# s) [. X# @% y$ J L- ]
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reset-ticks) r- d" F5 b% p: R: @6 G1 y' K6 t, w
end2 z1 o' _7 z% R; a, T+ w
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;; Initialize the global variables to appropriate values7 r% e& `$ q- S
to setup-globals
, [, g& R8 X; x set current-light nobody ;; just for now, since there are no lights yet$ Q% }6 P1 S& A# R8 a9 w
set phase 0
0 D h5 t, ~* O set num-cars-stopped 0
# d/ V4 o6 x% k' [' h* q+ E0 t set grid-x-inc world-width / grid-size-x
) s) k- a6 D6 L8 ?* p$ [ 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, |* ~! b2 K8 |7 f2 v
set acceleration 0.099
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,9 P4 W9 {. A! s9 H
;; and initialize the traffic lights to one setting- ]" a8 b: R( U1 b H
to setup-patches
% ? p( {( _) o/ w. i ;; initialize the patch-owned variables and color the patches to a base-color
& i3 z* ~- ?) m6 m* d# `; }2 O' I ask patches
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set intersection? false( R* d# S0 w% w+ A' _
set auto? false
8 u; W; E( {% C set green-light-up? true
/ `3 z: h4 U& W- ~ set my-row -1
9 _# E9 C& T& P0 S5 W, o0 o7 J$ b set my-column -1& |+ R2 a' q6 P8 j6 \$ I5 o+ w1 d
set my-phase -1$ K. J: j+ [( Q7 }1 `1 x4 `
set pcolor brown + 31 `* m6 D4 }7 r3 Q. G5 y) \8 H
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0 M: k& M5 ^5 ]" V9 S! z* I7 P0 C Y ;; initialize the global variables that hold patch agentsets# H+ o! f# I. ~8 H) L
set roads patches with
0 \: ?3 V# ^$ F+ [% A [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
' {: L: ]. |1 L2 o (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
6 i: ^- s/ y P' u' r% D set intersections roads with. x9 S% ~* P7 q1 {2 _ G: n k
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
# r u: I) Y s- G4 J( g (floor((pycor + max-pycor) mod grid-y-inc) = 0)]1 h! x8 E( Y$ ]3 \* ?
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ask roads [ set pcolor white ] ~# I1 i1 L2 v- o9 e3 ]
setup-intersections" a1 D2 Q8 S# r% |9 ?: D, X9 K
end7 r8 @. [: g' E" K4 j0 ~
其中定义道路的句子,如下所示,是什么意思啊?
" N# l1 h2 y, }+ }5 m7 C. y" I set roads patches with. ^ ?6 C* ?3 \# D1 J7 E- N
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or/ I, ^0 E8 R% G$ F' v3 Y
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]# D& W8 u. i7 z# B
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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