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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。& H3 L2 t2 F' f2 c
netlogo自带的social science--traffic grid这一例子当中,% [% \% k6 b3 W7 H# E N) O2 ~
globals
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grid-x-inc ;; the amount of patches in between two roads in the x direction
5 N/ j/ N2 Y2 I4 w grid-y-inc ;; the amount of patches in between two roads in the y direction/ J# j$ j+ g' x) G
acceleration ;; the constant that controls how much a car speeds up or slows down by if
6 P. U, A9 f! ]6 n6 N ;; it is to accelerate or decelerate
7 [' d: q* Q4 G; s+ k phase ;; keeps track of the phase
& ~4 m0 T' M6 ] Y, [. y% l Y num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
3 w: s: N; |* j' E+ N, r" [5 ?% t current-light ;; the currently selected light
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4 y% Q* Q. I1 ?" L4 Z9 p8 G ;; patch agentsets1 }8 Y; k2 S0 w& I4 U; T6 c5 b) ]5 o
intersections ;; agentset containing the patches that are intersections' A* s6 I' z; f: l& P. W8 i
roads ;; agentset containing the patches that are roads
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+ H5 H n6 f5 L3 E8 [/ t* Nturtles-own
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speed ;; the speed of the turtle& o+ O. e l+ l0 Y2 S
up-car? ;; true if the turtle moves downwards and false if it moves to the right
- [# _1 u9 S) R2 ]: o7 f4 ] wait-time ;; the amount of time since the last time a turtle has moved
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7 l4 S4 }5 G* l+ l3 apatches-own
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! N/ F {) D; @+ J' W intersection? ;; true if the patch is at the intersection of two roads
$ B6 c4 F+ _4 L4 w- y% R; F green-light-up? ;; true if the green light is above the intersection. otherwise, false." Q( t6 R4 ]/ B
;; false for a non-intersection patches.
3 D4 Q: w$ h1 E1 i6 w3 c$ o my-row ;; the row of the intersection counting from the upper left corner of the
1 l" f$ O; Z5 ]3 t* G% ? ;; world. -1 for non-intersection patches.' v; ]% \+ N# f: N+ p
my-column ;; the column of the intersection counting from the upper left corner of the
" S- m) \% I; H1 _: }2 x ;; world. -1 for non-intersection patches.( N; ]5 K, y/ g' K" I/ H
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
" v) v) y! S3 b0 |) q auto? ;; whether or not this intersection will switch automatically.: P7 @, T- d) f" d4 G3 F _" g% A3 V
;; false for non-intersection patches.
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) A0 u+ F& Q3 Q- [/ T: U4 [;;;;;;;;;;;;;;;;;;;;;;. x4 I4 Q/ w) y @
;; Setup Procedures ;;
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;; Initialize the display by giving the global and patch variables initial values.) W- Z+ c: h0 R0 n* E8 [
;; Create num-cars of turtles if there are enough road patches for one turtle to( {3 ]7 R6 d9 i P9 |$ m3 R
;; be created per road patch. Set up the plots.
; p% a% B% M/ ?' F* I2 Jto setup
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7 R8 O' h% V7 }. o- @ setup-globals) a% b0 a, K$ J5 Q- X* M
5 ], L! U3 F' n/ W ;; First we ask the patches to draw themselves and set up a few variables2 w# p: w0 E! M3 l6 q3 ^9 I
setup-patches* v: p. B. m" o( d: J5 U8 ]8 v
make-current one-of intersections& \, O1 H9 R; M6 N+ @% B$ R
label-current% M* y, C8 u" I
8 k$ Q% R1 n5 @7 j set-default-shape turtles "car"
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; |7 b9 v% u* r1 n0 W$ k if (num-cars > count roads). p0 ?- H2 F5 a* [; E$ F
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user-message (word "There are too many cars for the amount of "- g0 U) p2 _1 E, }7 V3 i }, K
"road. Either increase the amount of roads "
, O$ ^; T6 B- k; C% V4 h "by increasing the GRID-SIZE-X or ": y+ O7 j0 M. c) v- E/ I8 `+ ^
"GRID-SIZE-Y sliders, or decrease the "+ k3 `9 w0 S$ f; ^
"number of cars by lowering the NUMBER slider.\n"6 q; ~; j5 M0 ]; ^8 ^6 B1 l
"The setup has stopped.")
' U$ ~' f; p; S i+ e7 s stop
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;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color* y4 i6 }. N0 X4 f4 r
crt num-cars
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8 ^5 Q8 _; W' a: A0 s @ setup-cars3 F5 \8 k6 e' |6 @* p$ ]
set-car-color
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;; give the turtles an initial speed
( z; `" @) N2 ^% T! r& A: q ask turtles [ set-car-speed ]
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" T- V+ E! M# ~) I7 Q8 }1 R reset-ticks
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( l0 z% L# ^; l+ r( ^* @;; Initialize the global variables to appropriate values
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set current-light nobody ;; just for now, since there are no lights yet' ?6 O6 A4 R/ |% A' }6 C/ Q
set phase 0
) y% d0 m0 b. Z* D* ^ set num-cars-stopped 0, u) t& D$ V2 O8 x' ~. Q2 O
set grid-x-inc world-width / grid-size-x( ~) @+ P' p$ U. V) e O
set grid-y-inc world-height / grid-size-y% R9 c3 w5 ] O
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
% Q A9 h" Z8 W }; l# n! T2 t' E set acceleration 0.0998 t# L2 q' r4 u; G% A0 a1 X
end2 z* T6 K2 }5 X6 S: P3 B. P
) U, V9 l+ p) |/ T! I;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
5 k- m8 b( ]0 v# b;; and initialize the traffic lights to one setting( |5 M; F1 ?: l0 w& p6 y
to setup-patches f- ]; q7 ~# _+ V8 T& T4 R$ y! v
;; initialize the patch-owned variables and color the patches to a base-color
* s, i& A, K2 Q/ m$ I$ } ask patches
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set intersection? false+ s1 W) ?6 P4 n. P" z8 [$ a. L
set auto? false! P& c3 [) j6 S# i3 F
set green-light-up? true
* d& J0 p/ u! U: y( [: y set my-row -1
: c/ j- s. s9 }# s, k3 g set my-column -1
) ~( c" H; v* L/ Q set my-phase -1
Z* C7 a1 C$ h2 A8 g- e set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets
; q- C% \3 D2 u5 \3 Q1 D3 R8 o( B set roads patches with
2 u' W- K0 l$ p [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or( j9 P x4 l; i
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
; L8 u, v1 @' X* j0 u9 P set intersections roads with2 ^5 @1 R8 f6 b' }5 {5 o9 W- w y, x
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
; p8 T. i# t F4 f/ i3 ~- N- h (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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ask roads [ set pcolor white ]: v$ F, N5 P1 [& [+ I& a
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?$ T+ f; n( e7 r- _! Z
set roads patches with
! P9 S* R% ]( d [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
1 o6 ^3 ^( F0 H) j. f (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
; ~/ O* n$ K( }2 {% h8 N# |7 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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