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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。
$ g7 h% q' j* B O, K8 K) Xnetlogo自带的social science--traffic grid这一例子当中,
7 t) d' m& e& w8 N1 r) k! bglobals
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grid-x-inc ;; the amount of patches in between two roads in the x direction7 `3 }5 b. ~/ \5 V0 A0 S4 k$ \/ o
grid-y-inc ;; the amount of patches in between two roads in the y direction) B( s# @% G! d0 y
acceleration ;; the constant that controls how much a car speeds up or slows down by if1 C8 ]7 X4 }$ h- }. P3 `4 W1 S
;; it is to accelerate or decelerate) I' h2 ^ x3 O9 y
phase ;; keeps track of the phase
: B! H: E% P* F; j/ Y2 K num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure3 S: u4 V A; v8 N+ g" d
current-light ;; the currently selected light$ X9 F& F( H8 O
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;; patch agentsets3 c* J ^5 W2 [
intersections ;; agentset containing the patches that are intersections" X/ V2 ~' F) q- y( M9 |
roads ;; agentset containing the patches that are roads
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turtles-own
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speed ;; the speed of the turtle: ~$ k: [$ E8 `! o3 C* [$ t
up-car? ;; true if the turtle moves downwards and false if it moves to the right; d% w% Y/ X9 C& o3 S1 H+ s. ~
wait-time ;; the amount of time since the last time a turtle has moved0 T8 y9 ?3 V( [' |5 z8 @2 _$ L
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads O0 }; c$ A# _( g @
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
8 _; x& A/ W! H* v7 f ;; false for a non-intersection patches.! M6 [. `6 t% u. _, z1 p" G
my-row ;; the row of the intersection counting from the upper left corner of the# o: m8 J4 ?1 b2 ^% Z/ D
;; world. -1 for non-intersection patches.& T3 y' ?2 j r. N& c. f, @
my-column ;; the column of the intersection counting from the upper left corner of the7 K; y( N \: b }- d9 B: ~) F
;; world. -1 for non-intersection patches.
0 ?+ ]& e5 T) c9 N. z$ | my-phase ;; the phase for the intersection. -1 for non-intersection patches.% {5 q" c4 c1 ^( V. I* X" t1 e
auto? ;; whether or not this intersection will switch automatically.
* i$ t" W, A; F$ ]( U8 d( k ;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;8 N* M* t {& j/ Z
;; Setup Procedures ;;
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( _. }& P' {( b+ U P/ O;; Initialize the display by giving the global and patch variables initial values.5 r' }( K$ n2 e5 T
;; Create num-cars of turtles if there are enough road patches for one turtle to
- w" f; j- c/ [: g;; be created per road patch. Set up the plots.
5 l' w& z9 x& Z3 w9 Qto setup; f9 b8 P0 F* F9 V3 s# B
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setup-globals* ]" n+ ~: r/ X6 d2 k! r* W8 A
( T6 v9 q3 x6 r ;; First we ask the patches to draw themselves and set up a few variables, i" C- U+ o# M
setup-patches
6 ~: c8 S8 Q" T/ p: _8 C9 e make-current one-of intersections" y3 l% f0 E( `- f
label-current
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set-default-shape turtles "car"0 ?2 t& L4 x2 y+ R# X% f& l2 j
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if (num-cars > count roads)3 p4 y. F3 D8 M3 B$ h0 h- M; f0 _
[
. r5 T3 ?$ l$ O4 ~) Y user-message (word "There are too many cars for the amount of "# @0 ]1 j8 S6 v6 r
"road. Either increase the amount of roads "9 V4 N7 \/ {! L8 F- O) o/ X
"by increasing the GRID-SIZE-X or "% [4 k! p" j6 f5 ]
"GRID-SIZE-Y sliders, or decrease the "8 D- d4 P1 H! v, C6 R
"number of cars by lowering the NUMBER slider.\n"0 l0 k7 i3 w) {# C7 [$ P
"The setup has stopped.")
) s6 f8 U* x4 [ M9 ] stop
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7 _; j# d# e7 P* R {1 Z" { ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
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setup-cars' U( z P# Q" v" O* R
set-car-color
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;; give the turtles an initial speed
7 t$ z$ x7 h; ~* ~3 b ask turtles [ set-car-speed ]* y, o$ \# B9 A# ^- o; Z
3 T5 N3 s0 E) s: ?1 i reset-ticks
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;; Initialize the global variables to appropriate values
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set current-light nobody ;; just for now, since there are no lights yet! o. k' d. v1 A5 m
set phase 0: q9 r, @# x7 z- A
set num-cars-stopped 0; @* c9 ?4 d B7 c( }
set grid-x-inc world-width / grid-size-x
9 @! U8 j8 u* H% m6 {+ C set grid-y-inc world-height / grid-size-y
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3 @8 ?6 A* [2 s) K0 O ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary( u6 _& n2 A- E
set acceleration 0.099( p4 ?9 M4 ~' _4 ~% n
end; }7 p) d0 f* R2 R b) n" S
( g- h/ o L& t7 E& w5 L/ w0 u;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
D- O) {0 g( g;; and initialize the traffic lights to one setting. y" j; d. l4 i: j7 F1 u5 @( S- z
to setup-patches6 j; |& f; C. B3 E
;; initialize the patch-owned variables and color the patches to a base-color+ F- |; r, H5 q; y m/ F
ask patches5 k' Q6 F" T m: D- O. }
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( ]$ {$ ^ v+ ]( K0 k set intersection? false, ~ V" a5 e2 h
set auto? false2 s4 F4 C' C: Z# m. c
set green-light-up? true
& J. ~( N+ \- S$ N& u7 ]1 T9 ], L set my-row -14 Q7 }( s `. V6 |/ H; m) C/ B
set my-column -1, i' k" l( a6 v A6 i4 J1 H$ x2 m6 I
set my-phase -1% l1 w8 R' P) x* N. O
set pcolor brown + 3
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$ V( P% R- a1 a) u# O ;; initialize the global variables that hold patch agentsets
6 D5 R; B$ J2 B$ ^6 j set roads patches with: q1 ~, K' A/ o4 `: W
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
% x# o$ Z! c4 C# g9 @: @' I (floor((pycor + max-pycor) mod grid-y-inc) = 0)]+ S& K" ?( f9 X+ Q9 f" _6 q
set intersections roads with8 X6 r. l* y, E- Z) S
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and/ b2 @' V2 j* k* L. [
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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+ W# I! _- J9 L ask roads [ set pcolor white ]5 i0 [0 n2 v0 A1 E' L) r
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?
) g9 x2 ~& F2 a, I; @8 |4 C( a set roads patches with3 Z8 U9 {9 |+ N* ?
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or3 f$ L5 Y/ t1 P; O8 ?
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 ]# x7 Z' U: g' F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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