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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。7 I0 M2 r0 F, H$ n; z0 Y
netlogo自带的social science--traffic grid这一例子当中,
9 o8 O4 |6 E( g& qglobals
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, z3 k$ o9 _. h O S; T: l0 d+ J$ y! y grid-x-inc ;; the amount of patches in between two roads in the x direction
# p2 y; o7 s2 e- ~9 L* X grid-y-inc ;; the amount of patches in between two roads in the y direction1 z7 ~! r) {& V0 Y4 }
acceleration ;; the constant that controls how much a car speeds up or slows down by if
e. } s& S/ ? ;; it is to accelerate or decelerate
4 Z0 I3 h! ] Q& h phase ;; keeps track of the phase' c+ b5 v& @' I, o1 r3 A
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
, W k; M& u# l5 [3 x% O current-light ;; the currently selected light
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;; patch agentsets2 i6 ^5 }! a& B ]
intersections ;; agentset containing the patches that are intersections+ f7 Y$ h: K; G
roads ;; agentset containing the patches that are roads( V7 K/ f3 ?2 ]' v/ s8 Y
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turtles-own
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" x, r, _/ e& d4 t speed ;; the speed of the turtle& L- }3 @3 t1 R3 J$ K% H- w
up-car? ;; true if the turtle moves downwards and false if it moves to the right6 R% U1 _( o9 c% A' R( u( c
wait-time ;; the amount of time since the last time a turtle has moved
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& q: e; z% u- G1 y1 |4 spatches-own2 w2 Q' ]4 J( C+ V% I
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intersection? ;; true if the patch is at the intersection of two roads/ m# `! d- L g* f7 b' w# h) R
green-light-up? ;; true if the green light is above the intersection. otherwise, false.1 {8 x* W; p! n+ D9 g7 G {" k6 K
;; false for a non-intersection patches.
- `) F& Z1 ^2 b/ q5 V2 { my-row ;; the row of the intersection counting from the upper left corner of the
8 N: i1 U4 {4 p2 C4 j, ?( g ;; world. -1 for non-intersection patches.; Z4 @5 m) P" I+ Y# @& K, M
my-column ;; the column of the intersection counting from the upper left corner of the
: \9 \3 k& p* {' e$ M ;; world. -1 for non-intersection patches.4 O/ R d+ H% V$ v* t" f
my-phase ;; the phase for the intersection. -1 for non-intersection patches.7 I) O) i4 n& S g% _9 Y
auto? ;; whether or not this intersection will switch automatically.
" L; O0 _( ]- ?. C ;; false for non-intersection patches.5 x; l6 J6 b# p# o0 [* {9 e
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;;;;;;;;;;;;;;;;;;;;;;3 G" Y8 A- b% S% k3 z& t
;; Setup Procedures ;;$ X2 X6 Z+ D- I: h {+ s0 q
;;;;;;;;;;;;;;;;;;;;;;5 P/ b6 S) M7 Z+ N6 p
% T4 \0 I3 y: ?+ W;; Initialize the display by giving the global and patch variables initial values.
8 x4 `4 C6 N5 V;; Create num-cars of turtles if there are enough road patches for one turtle to
" T, k" E$ t* u;; be created per road patch. Set up the plots.4 O5 b8 b o) A
to setup% x: a' j l9 _5 _; q
ca
" a6 T B$ [4 r setup-globals+ b( D% m, E( r
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;; First we ask the patches to draw themselves and set up a few variables
7 o! \9 H2 U& x a& w" }" y: O; m! L: Y setup-patches0 l# z& P# V. H# Z: O9 h6 g5 z
make-current one-of intersections. w0 t7 z7 b% t& E7 f0 P2 ?( R' \; [- ]
label-current
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set-default-shape turtles "car"
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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 "( o+ M' @6 ]: o6 t+ h8 X6 R
"road. Either increase the amount of roads "( X, w9 L: [- z8 ]* Y x
"by increasing the GRID-SIZE-X or "
/ t7 X* g5 l( i, y3 ^! b "GRID-SIZE-Y sliders, or decrease the "
8 F- o) _/ h- D; Z3 j0 I "number of cars by lowering the NUMBER slider.\n"& Y) V6 F" {- U5 U
"The setup has stopped.")5 d) ^1 ?' V* Q, R
stop
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6 r7 D9 J; ~' o7 _8 L) J! \ ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
' T' m9 |1 [' O0 F2 _$ g7 Z crt num-cars& C6 G( v. P+ O* G& H2 {
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setup-cars0 A& P* `- V* ]3 c$ k
set-car-color
+ ~9 u' d" @& R5 ] record-data
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( m2 [' S6 L( [2 U2 f/ K ;; give the turtles an initial speed
' `6 ?, p4 B5 j+ w4 z' ` ask turtles [ set-car-speed ]8 N2 ?. M e" Q) i8 X5 b% `+ L5 N
) x: ~6 }3 I3 @) v: T" t reset-ticks% w7 d+ m+ K) w& T" G# y% u
end4 Q0 O. L0 I& R/ A5 D" |; L
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;; Initialize the global variables to appropriate values8 y/ i% I! n* j }8 w
to setup-globals7 ]8 D7 @3 _9 ?3 q6 u5 D
set current-light nobody ;; just for now, since there are no lights yet
% K! E, ^, V- q B* _8 L set phase 0
0 ]5 w, A, G( B set num-cars-stopped 05 H% [. s1 r4 I6 d3 Q& N" b5 [
set grid-x-inc world-width / grid-size-x d) [8 h1 R" H4 v
set grid-y-inc world-height / grid-size-y! L6 M" ^; \! [& S0 P# n2 j1 z2 E/ c
& ^- ~/ {, T; W ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary* @" t9 V0 ~& F$ u+ z n
set acceleration 0.099
1 }, ^$ D+ L8 [$ s7 ]' R) I; mend
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
' P. x3 g) L' x# @;; and initialize the traffic lights to one setting9 i+ v8 C i* @) ~
to setup-patches
3 p3 ^/ T4 _# ~. q ;; initialize the patch-owned variables and color the patches to a base-color
, ?, s8 j# Y" h& a. _ ask patches
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set intersection? false
: g, H3 r% a8 f: Q set auto? false
K8 L( i" ~4 h set green-light-up? true( b0 c `# V( I' p5 G- `$ v/ ]
set my-row -1* c8 D9 b( V- I7 J
set my-column -1
. b5 ]$ E: a$ \6 S$ x set my-phase -1
. e U; v1 b8 T, j! M8 X/ ] x set pcolor brown + 3/ z) e+ n a/ e; |1 B7 n% K4 ]2 A/ e
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;; initialize the global variables that hold patch agentsets
6 D' U" E: d4 ~4 N) ~0 Q$ u set roads patches with
+ o* h- `+ g# Y' {0 g8 Y [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
0 m Z" X& g: w% d2 a% j (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
0 z" p2 [- c" `9 k e& _4 ^ set intersections roads with
1 ^' B1 q# A& n" F: [3 P [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
; R/ k2 Z/ k* f! O (floor((pycor + max-pycor) mod grid-y-inc) = 0)]9 a5 i% K" R# X2 [
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ask roads [ set pcolor white ]
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end
2 ^3 b, _1 X' z1 T: D其中定义道路的句子,如下所示,是什么意思啊?
% l. p& a1 I8 a set roads patches with
. w" T8 D' ]% o n. ?& H( b3 Y9 X, b [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
8 p% y1 n! f1 r6 X (floor((pycor + max-pycor) mod grid-y-inc) = 0)]1 n4 I% k% F. V3 G
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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