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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。
: E. u3 N5 S/ X1 U+ s0 cnetlogo自带的social science--traffic grid这一例子当中,& T4 j, v! N4 h- k# p6 {
globals
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grid-x-inc ;; the amount of patches in between two roads in the x direction' p j4 M2 u3 e( l
grid-y-inc ;; the amount of patches in between two roads in the y direction2 _& {* h' U+ ]! P# O C9 n8 M8 P
acceleration ;; the constant that controls how much a car speeds up or slows down by if
2 @# z2 a/ F9 ~ z! W ;; it is to accelerate or decelerate- d! e; u; m, t4 W6 ]- w( t
phase ;; keeps track of the phase
5 r. J" ?8 r& Z/ `; A num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure+ a* w3 t! W: p6 b1 H7 v5 {' D
current-light ;; the currently selected light2 k, d9 d7 ?1 H) {* s# A
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;; patch agentsets
1 y8 T- T2 d. N$ G; k6 t" A. H intersections ;; agentset containing the patches that are intersections1 y* K8 _, y: k0 X
roads ;; agentset containing the patches that are roads: |& f! O( v# C8 ~7 E/ w/ N
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* ~- c, \0 \# Rturtles-own6 o7 V% Z1 T) K! W: m
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speed ;; the speed of the turtle( r: Z R, w: @* E8 X$ b6 t
up-car? ;; true if the turtle moves downwards and false if it moves to the right# B: t3 N# V" x# @: ]+ B
wait-time ;; the amount of time since the last time a turtle has moved
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patches-own0 D! f$ g- j' U7 c
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intersection? ;; true if the patch is at the intersection of two roads! e) R3 z+ o9 T# \) E
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
/ ~5 ~8 ]6 t* m& C O ;; false for a non-intersection patches.
$ Z5 p# N7 q8 X! U! E# u my-row ;; the row of the intersection counting from the upper left corner of the# n( U: L: a+ G8 v0 N1 R
;; world. -1 for non-intersection patches.
' P: N6 e7 K4 C) J my-column ;; the column of the intersection counting from the upper left corner of the: v5 J6 u% T0 [/ T9 s
;; world. -1 for non-intersection patches.
9 j% K$ G) D/ @6 A my-phase ;; the phase for the intersection. -1 for non-intersection patches.
" M. S( A6 D& _% H auto? ;; whether or not this intersection will switch automatically.
4 h. [# T M6 W0 L$ ^2 M/ Z ;; false for non-intersection patches.
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$ A- s* }9 w" i- X5 z7 t, h7 o;;;;;;;;;;;;;;;;;;;;;;
% S7 N S$ |. E3 [* V, F! I;; Setup Procedures ;;. M; O$ v) s$ S: L
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;; Initialize the display by giving the global and patch variables initial values.
; t! d2 `# D( {' ~# A8 X;; Create num-cars of turtles if there are enough road patches for one turtle to
S; A2 V/ D8 b* `5 \;; be created per road patch. Set up the plots.
1 d( l% S. n8 K1 ?! lto setup
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setup-globals3 J- z( }/ U% ~
7 g) r) }6 t; c1 b* M1 |$ H" w0 o ;; First we ask the patches to draw themselves and set up a few variables- ^3 p. P! ?# [5 _
setup-patches
0 b9 l# w) M, h% F, B: | make-current one-of intersections
& G- q. T! q/ A label-current
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0 o) ?/ \, I% I% [: f, d3 E set-default-shape turtles "car"( }# j& v& t; s" c$ n, a
& J0 y7 {# Q2 h8 h if (num-cars > count roads)
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user-message (word "There are too many cars for the amount of "2 E+ D& P k4 @
"road. Either increase the amount of roads "5 q3 Z- ~/ @7 h( u2 E
"by increasing the GRID-SIZE-X or "
4 J. ^- Q9 `9 H) f- f/ H "GRID-SIZE-Y sliders, or decrease the "- ]6 ?: ?8 u* U' v) B k
"number of cars by lowering the NUMBER slider.\n"+ z, e' I! g" T; |* u1 X! W R- t
"The setup has stopped.")$ u& i5 l+ Q! F9 C$ y& o; J
stop+ F& [! H) c' _7 Y: K! M, S
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( X% m2 h( p3 D ]4 v ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color" k- s j4 d) W" ]* a/ R
crt num-cars
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setup-cars
7 f# e, b/ d c7 v9 t+ X: X" s( ^ set-car-color4 a- ?. z3 E, z, a
record-data
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" y0 ^% F5 l& R$ ` ;; give the turtles an initial speed
! S- ?) m. e1 g1 B6 j- N ask turtles [ set-car-speed ]/ F/ G( s+ d6 H2 o
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reset-ticks
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;; Initialize the global variables to appropriate values
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) G9 H, X! N5 z' g! Y8 ~ set current-light nobody ;; just for now, since there are no lights yet. I& d3 c' F7 X3 N8 P6 G7 Y r
set phase 0- ?% X! f3 I/ O+ p) }
set num-cars-stopped 0
4 b, k1 g! y5 g7 } set grid-x-inc world-width / grid-size-x
; p# u! c' V' r% x0 v set grid-y-inc world-height / grid-size-y( ]* N+ }- m2 t/ m
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
4 E [6 ^! H; v" M- ~ `4 | set acceleration 0.099) n# d; O0 g; \
end
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8 K5 {/ k# t& m( v3 {;; Make the patches have appropriate colors, set up the roads and intersections agentsets,7 Y$ f- T" W/ a" [
;; and initialize the traffic lights to one setting3 i% k' [3 g: @
to setup-patches
4 g) K8 r0 A$ ?' ?! ^+ o ;; initialize the patch-owned variables and color the patches to a base-color
% ]2 a5 ^% Y6 {" O0 e/ U% K% t; m ask patches' O5 _/ K L' s; Z
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set intersection? false# B0 M0 u9 ]1 l, Q2 g9 h
set auto? false
# t: V1 x8 D) R! e' ^1 c( [+ { set green-light-up? true
/ D; a5 |& O4 b set my-row -1) B- x$ d6 U; t1 {: t
set my-column -1
9 ]/ c" [( [0 O: v0 T, w% t set my-phase -1
9 O1 s0 B3 r9 ]8 o, K3 Q, t1 ^ set pcolor brown + 3
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;; initialize the global variables that hold patch agentsets! w* }/ T8 Q+ }. g3 D4 j
set roads patches with
% S% [) m( M' Q* f) |4 O [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or( q6 u" R" F$ c7 _ B4 `: j
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
/ o( [; O7 ]9 I$ w! c set intersections roads with+ [6 D4 x) @0 {
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and' L' S% x1 f, X0 g2 p ]: S
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]2 ?: u8 k" l$ ?8 d
. W G9 h* C9 c4 r M/ A4 N: X ask roads [ set pcolor white ]4 q4 N& U: t* H& J3 M
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?
; h# _/ N3 B& u8 t$ O" q& `* f; [! c set roads patches with
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(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
7 m$ O4 F! \) L4 V, N5 v. c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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