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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。- i! u; m" p- K+ R. j
netlogo自带的social science--traffic grid这一例子当中,
" a% d4 |8 A. g; gglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction8 E- @; H9 w5 a2 J; Q
grid-y-inc ;; the amount of patches in between two roads in the y direction @/ y: x, M" ?0 ^8 s. p
acceleration ;; the constant that controls how much a car speeds up or slows down by if& G1 A/ ]* T2 m$ o, e; G! W" R2 F
;; it is to accelerate or decelerate
! v# L. ~" k: _ phase ;; keeps track of the phase. t- G; s* S% l
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure8 m" ^5 G/ t O/ M# @) H
current-light ;; the currently selected light" f4 V ]3 ]# o- q
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;; patch agentsets" W' B6 ]( z# O; b3 i8 E
intersections ;; agentset containing the patches that are intersections
4 w0 D6 y4 ?$ V: X. P- y roads ;; agentset containing the patches that are roads
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( B6 s: o& h/ Y( J. qturtles-own# J& `4 k2 j- `# [- R
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, x4 j9 C/ w% u) m speed ;; the speed of the turtle A$ @/ F9 d9 l
up-car? ;; true if the turtle moves downwards and false if it moves to the right
: ^5 ^8 L8 H* G6 v. F4 G! j wait-time ;; the amount of time since the last time a turtle has moved! J! B2 _; }- \9 T
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: {$ ?5 D, L& F; Ppatches-own+ U% Q7 U' w+ m% ~3 ~
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intersection? ;; true if the patch is at the intersection of two roads' {; u- W: V0 l f4 f
green-light-up? ;; true if the green light is above the intersection. otherwise, false." l) e9 n! @' R/ W
;; false for a non-intersection patches.
. H8 I. A0 }4 j' I# b6 ]/ }( [, z9 V my-row ;; the row of the intersection counting from the upper left corner of the4 ]7 Y) }$ X, u: n$ R* L
;; world. -1 for non-intersection patches.& ^% u6 ]9 p$ G. W7 Y$ ~9 o" ?
my-column ;; the column of the intersection counting from the upper left corner of the4 @4 ]) x; h* @4 k9 k, ^
;; world. -1 for non-intersection patches.
. b! z" t/ j' x my-phase ;; the phase for the intersection. -1 for non-intersection patches., O5 m, s6 x `5 l
auto? ;; whether or not this intersection will switch automatically.
5 c1 `5 J) B; M! _* r ;; false for non-intersection patches.3 L( H& L2 ^5 s: Y' j
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, q7 N1 g( }" Q& M7 O6 \& b" w;;;;;;;;;;;;;;;;;;;;;;
8 y; `+ R1 a4 s# t. o;; Setup Procedures ;;( \) A* c& T$ ]2 j9 Z
;;;;;;;;;;;;;;;;;;;;;;
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& N4 }7 _& [, S ~5 T% e;; Initialize the display by giving the global and patch variables initial values.
. w5 J0 \3 {1 H;; Create num-cars of turtles if there are enough road patches for one turtle to
; N- _( L- [ s;; be created per road patch. Set up the plots.
8 \5 D6 q9 D. Mto setup, \" m t8 p: ]8 A- M- d& D4 Q- H
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setup-globals4 S5 E! n% b) Y0 Z
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;; First we ask the patches to draw themselves and set up a few variables
1 L+ A8 I# M# H8 [" O, Q# w setup-patches
: E* X8 U, \- J8 A' F D R* ` make-current one-of intersections
8 G' T4 e6 C, e" L0 l0 L label-current
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$ f8 X& X' W9 i' n set-default-shape turtles "car"2 X% X7 I+ S' w% k) Y5 b% l
& K% m- c) E& R# O) j% w4 I if (num-cars > count roads)1 I; O9 o0 V- n6 L7 U" k% y6 o% D
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user-message (word "There are too many cars for the amount of "
! S: l6 K* W1 |; Y/ \ "road. Either increase the amount of roads "$ U5 x2 c+ q0 m, r
"by increasing the GRID-SIZE-X or "
; m; t, Y/ @; L. m; A+ t: J" { "GRID-SIZE-Y sliders, or decrease the "* L I+ f R) e9 A# }
"number of cars by lowering the NUMBER slider.\n"- T, b/ I6 ?5 y$ P4 |* P% \8 |
"The setup has stopped.")
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color$ C' k& z% v/ L1 {1 [, Z
crt num-cars, ?2 ^% T. v) Q! i4 _) \8 p
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( x0 U. B; `. n* l; @ setup-cars) }* R: K1 V. J; y
set-car-color
8 E$ ?/ J4 _) k record-data+ W9 j1 B @5 j7 u3 n' U
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;; give the turtles an initial speed
+ x/ a; ?. V/ c! C ask turtles [ set-car-speed ]
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reset-ticks+ L2 V: o' u2 [+ {+ b
end; T0 w) v/ _+ n& ~3 [6 _/ j
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;; Initialize the global variables to appropriate values
. \/ N+ d" h/ z3 Jto setup-globals- ?2 {8 y8 P9 b p$ z( Q7 Z' r' V
set current-light nobody ;; just for now, since there are no lights yet2 _# ?! S. @, m% H- m% U
set phase 0
+ Y) H; W, }6 d A set num-cars-stopped 0
' ~7 d) j% P* q) U set grid-x-inc world-width / grid-size-x" R- }& g; z( y# T! E
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
. d8 x3 a* l5 l: i1 U2 N set acceleration 0.099: `( g/ |. g K" b& y! Z/ e
end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
: @6 h% @* j5 m! I: p) _. E3 n;; and initialize the traffic lights to one setting, J! ~. g$ P7 f9 \1 P* R" }
to setup-patches8 C" h1 u% m6 r# h% M/ k0 u
;; initialize the patch-owned variables and color the patches to a base-color- l# t+ m/ O/ @; X8 v
ask patches4 Y# @( Z4 j' O. O6 T
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/ d8 J& ?5 v! h! B set intersection? false
s. c& x& r& f9 H, H set auto? false$ l6 C( |4 [+ p% G1 p. w! u
set green-light-up? true9 l% `/ H0 F0 g
set my-row -1
& H" z9 C$ k: S' C; }& t5 d2 E9 g set my-column -1
' W8 [6 @6 s" [6 h; v& z set my-phase -1
$ S7 E! f' z3 O7 ^& o2 ^. `( ` set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets
3 w6 _- ? x* f! _ set roads patches with
1 Z# w) b! [) p [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or2 N- K( o+ O# `: W! r
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]+ \; o9 A, m7 _. D" K: `
set intersections roads with
) _5 k% }9 y: W+ C8 j [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and% J7 T# L$ [7 ^5 T# j% G
(floor((pycor + max-pycor) mod grid-y-inc) = 0)] k0 \2 |2 v/ E0 J0 z2 O
' _+ X8 b6 A% N$ ^# D ask roads [ set pcolor white ]
/ Z$ k' o" `4 M5 A q 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?. N5 z& A, }" w- e1 F s
set roads patches with
3 D/ ]( b( Q5 G2 \, w% i8 z [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
$ K0 y7 n/ r4 Q* @: E6 ^1 n$ u (floor((pycor + max-pycor) mod grid-y-inc) = 0)]6 j2 ?+ j! a0 ]$ N; H: G0 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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