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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。+ K; t( j' d1 x* x O5 O
netlogo自带的social science--traffic grid这一例子当中,
, ^8 I$ o7 Z$ H1 Kglobals; t4 v' V$ Y1 E( t7 @7 ^
[5 x' c# t$ _- W& f3 Y% _
grid-x-inc ;; the amount of patches in between two roads in the x direction5 Y& v& V0 l4 p/ W
grid-y-inc ;; the amount of patches in between two roads in the y direction7 K* c+ e: k6 T
acceleration ;; the constant that controls how much a car speeds up or slows down by if1 ^% l8 i3 _+ X" ]- ^
;; it is to accelerate or decelerate! w$ S$ }. c1 K! O7 A, U/ v9 G
phase ;; keeps track of the phase& t9 G+ H6 z' H% W1 e3 W
num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
% W; U9 ^0 |1 E current-light ;; the currently selected light
0 p: r1 s1 A7 S7 n5 F- }# w
% G; ~4 N2 D! _5 s% f1 q7 z ;; patch agentsets
$ I& { T3 r% C' A intersections ;; agentset containing the patches that are intersections) n2 a' ~- N2 a, y
roads ;; agentset containing the patches that are roads
# J7 @7 V$ `: m x. R" {]+ `( K6 i6 P; F. i+ d
7 m& `5 ^ J1 c5 nturtles-own N! ]# Y+ C( a
[6 M4 Q1 \5 {6 O+ {" p4 ?* I! m4 \
speed ;; the speed of the turtle% B- d' K: E. a% O
up-car? ;; true if the turtle moves downwards and false if it moves to the right
* D7 j6 }4 O( y# B+ Z4 V) Q wait-time ;; the amount of time since the last time a turtle has moved+ U0 [/ q3 x$ k" ~0 [9 r4 }' f6 R* Q
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patches-own
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intersection? ;; true if the patch is at the intersection of two roads
" x# [: |' s8 ?' h green-light-up? ;; true if the green light is above the intersection. otherwise, false." w/ V" `. F- L. R' l
;; false for a non-intersection patches.
1 z- a0 s ?8 V6 y$ i5 d0 \) `( [ my-row ;; the row of the intersection counting from the upper left corner of the
/ l- t$ N7 H. z8 J ;; world. -1 for non-intersection patches., P5 S3 d. h7 r
my-column ;; the column of the intersection counting from the upper left corner of the
1 f7 C' d K v+ _# x4 x0 D ;; world. -1 for non-intersection patches.
$ t" c9 R. X% s my-phase ;; the phase for the intersection. -1 for non-intersection patches.
& X7 T8 B, e4 o0 {- [* o( K9 s auto? ;; whether or not this intersection will switch automatically.
* \0 ]" Z; Y9 X) K z, b$ p" v9 J9 C1 U ;; false for non-intersection patches.( H+ J) I: V! Y) @
]
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;;;;;;;;;;;;;;;;;;;;;;& A, g% i% I. u* S
;; Setup Procedures ;;% S0 `0 r* ~/ b
;;;;;;;;;;;;;;;;;;;;;;
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7 n' c/ y& f' j& K;; Initialize the display by giving the global and patch variables initial values.* v/ z/ U+ [* Z- ]4 N
;; Create num-cars of turtles if there are enough road patches for one turtle to* K( D+ j9 i' d: q1 e% b3 w' G5 M
;; be created per road patch. Set up the plots.$ q: M) c' T8 o. e) d9 C! W9 i
to setup
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J4 c9 E& I. ] n, Q0 u+ ^' T setup-globals
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;; First we ask the patches to draw themselves and set up a few variables: t% C9 ^$ j! T# y: R1 H
setup-patches8 k6 q$ }1 l2 ^1 [8 t9 z
make-current one-of intersections
4 l' k5 m0 D% n label-current, ?' K, L2 ^* L; H! q
" u: Q6 }+ |1 f" C
set-default-shape turtles "car" P, u% [2 @7 j
q; F- ]3 E. `4 z if (num-cars > count roads); @4 k: e8 d9 R7 b5 D% w7 i( s
[, B* B) d/ l8 R0 U; D" o
user-message (word "There are too many cars for the amount of "
5 W% o7 M8 Q8 d2 V M0 \# u+ |2 P "road. Either increase the amount of roads ". M ? a7 y' P2 U/ s7 J* |# M, D
"by increasing the GRID-SIZE-X or "
5 S% Z N3 G/ C, U$ ?/ H, {8 v ^' T E "GRID-SIZE-Y sliders, or decrease the "# X$ g' s, @' l4 M; e" q
"number of cars by lowering the NUMBER slider.\n"
& v! C9 y: b2 j" c: a1 ^" d "The setup has stopped.")
: y, e# K% {7 B/ V" m1 T! a8 f stop8 C6 ~! J) K) i, a1 r
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% x. N, }) n: E. ]" o* L ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color( c. A& S/ ^. d9 I
crt num-cars
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setup-cars
0 P) x* G7 ^; I+ _: S) Q# Y, ?* b set-car-color
. p$ j7 ^8 E3 A {* m0 `* N record-data
6 C0 v& [0 {: U* K" [1 K; P ]8 Y& x0 k% E6 S9 H
# O: ~4 Y2 p; ? ;; give the turtles an initial speed4 x- l9 M) P; }; W0 K# Q# W
ask turtles [ set-car-speed ]
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. u1 y( Z# e7 D o( R reset-ticks2 q/ ?) x6 w5 E7 {
end
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! m1 E6 H0 S8 t4 F$ C;; Initialize the global variables to appropriate values
) j# E, `; b' D" J/ ]to setup-globals
5 {" F: t8 w8 J set current-light nobody ;; just for now, since there are no lights yet/ X/ S( r3 a, q8 j1 F
set phase 0
8 ?' \ {7 B+ O* }& }' B( l3 D set num-cars-stopped 0* T+ p' Y, O( l
set grid-x-inc world-width / grid-size-x
* A1 n; C/ S- R+ q8 C5 s4 G set grid-y-inc world-height / grid-size-y( ^% P' j) @$ V3 B
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary/ N- \& N' w5 V, U8 Q& O$ C# E
set acceleration 0.099
; `7 l& H7 z7 L' eend
3 q2 `% I7 r" Q6 G0 C. N/ i- r6 F
;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
% g1 \0 [; Q% x" ~4 `" H- K;; and initialize the traffic lights to one setting! d3 ~7 ] C3 E. k/ i
to setup-patches% P1 m; c3 n: ]
;; initialize the patch-owned variables and color the patches to a base-color7 O+ D& Y1 ~; P, G! T7 `8 s; e
ask patches
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set intersection? false
; V- h4 N0 y" |# W, g/ i set auto? false! s4 U" N5 x4 L2 G3 x* Y, B! C1 L
set green-light-up? true5 |2 M# ~( E: p$ n- @8 n; S
set my-row -1
7 U& T5 Q# ^2 Z; d) m set my-column -1( n4 q& _1 i1 {( w
set my-phase -1
4 _1 S) U2 s% W7 {- d set pcolor brown + 3
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5 U) g3 |& _% Y+ C4 ~/ n
;; initialize the global variables that hold patch agentsets( a: {3 p ?* ?9 E& Z, \- b
set roads patches with
0 f% V4 F- ^. d# ]) M# i [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
) o+ H4 N: M' `2 c8 p9 J/ o v (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
2 E! [8 f$ \7 G4 L& E4 o) U set intersections roads with
( `; J' @* o% T3 n8 ] [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and: g) V. R1 V/ R2 X& \
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]; Q" Y) U( \& M4 b) I9 ]! v z3 i
: ?4 o G! Z* I, _9 @# p4 { ask roads [ set pcolor white ]) j& h. I0 k% a$ n; Y/ p% w* v7 u
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?
- M, c8 \6 T7 ^# M8 n2 u. c set roads patches with
# P/ a) ^: G- d _, X3 v8 S8 W [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or- a0 W+ m/ ?2 e7 t. k4 {' ^5 I/ ]
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]# O" K) P$ F7 ~$ b. Q! H# s" o
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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