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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。
$ p3 J; @2 B0 z: w' Anetlogo自带的social science--traffic grid这一例子当中,9 i. V# t: y( b* k
globals
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grid-x-inc ;; the amount of patches in between two roads in the x direction
4 O2 ]9 I( D4 }2 f grid-y-inc ;; the amount of patches in between two roads in the y direction
+ M; @3 E" k% b( N% h; R9 O) i acceleration ;; the constant that controls how much a car speeds up or slows down by if
$ e, U; A; b F7 O) y* R ;; it is to accelerate or decelerate6 K) K* R$ e K2 p$ p
phase ;; keeps track of the phase
( _1 o" S4 u( Y* q% d( Z3 y2 r num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure
0 }( g. s/ m( [2 D. @$ | current-light ;; the currently selected light
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1 Z1 [, W/ a1 H ;; patch agentsets+ z s& c' Y/ B5 N) t$ e8 @2 P) f
intersections ;; agentset containing the patches that are intersections# p7 X- c4 l/ O! V" G* K' w
roads ;; agentset containing the patches that are roads
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turtles-own; k" r; R# T& x
[
0 S2 S; D0 U/ [# @ speed ;; the speed of the turtle* `. H$ h3 x) n( Q U
up-car? ;; true if the turtle moves downwards and false if it moves to the right0 q4 w4 i! B* h! ]$ B( }0 W
wait-time ;; the amount of time since the last time a turtle has moved; f2 H3 [* ~9 r7 S3 g
]
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* j2 @( K( g9 ^7 s3 Bpatches-own" @1 ~; o W2 _# h6 ]8 A9 k
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intersection? ;; true if the patch is at the intersection of two roads" ?* z; D% N; O" p
green-light-up? ;; true if the green light is above the intersection. otherwise, false.; c& U" W) [& N; g% v
;; false for a non-intersection patches.
8 m7 P% k- ]' x) d/ O my-row ;; the row of the intersection counting from the upper left corner of the
8 l0 P" C- {4 y/ e5 j S e/ U) x ;; world. -1 for non-intersection patches.' ^0 g1 J8 G. J. C$ X2 Y& p
my-column ;; the column of the intersection counting from the upper left corner of the
8 I# @( O1 U9 | ;; world. -1 for non-intersection patches.* b E8 O8 c2 U
my-phase ;; the phase for the intersection. -1 for non-intersection patches.4 K+ [3 [6 a/ w
auto? ;; whether or not this intersection will switch automatically.+ [$ |0 r4 d: P3 W2 ?
;; false for non-intersection patches.
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;;;;;;;;;;;;;;;;;;;;;;. _; P; m$ k8 d: N3 u6 V# I9 D
;; Setup Procedures ;; C. l- N! O: q6 C: D
;;;;;;;;;;;;;;;;;;;;;;9 n7 j* ]- R+ F8 e# H
7 P: ~+ A. o* F0 }0 d( t;; Initialize the display by giving the global and patch variables initial values.6 |5 G! v6 O R q5 y4 Z: v
;; Create num-cars of turtles if there are enough road patches for one turtle to
3 I: T9 S% D# p3 O9 K/ B- v;; be created per road patch. Set up the plots.5 h5 V% }5 W0 e+ c8 a
to setup" h8 \* H5 d9 E( @* m
ca
" Z' i; T$ U' i) K+ V6 k setup-globals4 e z& V0 E; V; M4 K* ?9 W
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;; First we ask the patches to draw themselves and set up a few variables
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make-current one-of intersections
9 {7 N0 G- P, I. ~) ]! q$ V label-current' X2 J7 N1 T. N" @1 P% i
; N! K/ H0 F% O2 |1 `# i1 q set-default-shape turtles "car" }# C* g% m Q! o: d) `
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if (num-cars > count roads)/ T8 t5 z4 ?- S" ^% B- Y
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2 U( b6 T# k& L- n; }8 V user-message (word "There are too many cars for the amount of "; p7 e( o/ I( F M& f1 J8 L
"road. Either increase the amount of roads "
5 b+ ^" A% [0 q8 t0 J& g% _+ S% o6 u "by increasing the GRID-SIZE-X or " K' I @0 v: g' h
"GRID-SIZE-Y sliders, or decrease the "
. p3 |+ ~) H4 O n/ r "number of cars by lowering the NUMBER slider.\n"0 l4 a0 p! ?6 _$ h ~9 d; Y9 O
"The setup has stopped.")0 M" p! P/ B" ]% U. Y
stop' U% s; J. @! g3 R* Q& ]! k- |
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9 e& X$ a9 J& H3 B% D. j$ P ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
; v! W2 E/ I5 R crt num-cars
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setup-cars* H. `- s2 ~) L8 K# B
set-car-color) p/ q8 |0 s4 b" h! _
record-data
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;; give the turtles an initial speed" A2 m$ v t2 ^" j1 F# W% z; R
ask turtles [ set-car-speed ]
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! r( j6 Z7 G2 I+ s3 g# P reset-ticks
9 h9 R1 t8 n# {$ ?- uend
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2 i' Y) l' g: Y' A; o! s( \, O;; Initialize the global variables to appropriate values
5 m' v3 k2 h" {$ P* d- v$ Uto setup-globals
) a5 F$ N! [0 e# O9 x set current-light nobody ;; just for now, since there are no lights yet: Q# W+ Y) Z9 } \: P
set phase 0
- ?% k% Y" C0 `3 N* r set num-cars-stopped 0. [; ~0 |& A; p {/ u# y7 y
set grid-x-inc world-width / grid-size-x
8 U T7 O) P, ?. e. w- t% }' M set grid-y-inc world-height / grid-size-y
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;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary
! f8 i. g2 W% P0 f" r& n2 e2 x set acceleration 0.099
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
0 v" e' J) Z! x6 p e, q;; and initialize the traffic lights to one setting
, }# Q$ U4 v9 d# ^4 Nto setup-patches
! ~) N( ~; a9 f( Z$ x; v ;; initialize the patch-owned variables and color the patches to a base-color
* a- {" X q( g ask patches
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set intersection? false; ?! n: @ ]0 X. o! j
set auto? false7 c' s- C& O# }, l
set green-light-up? true2 f2 d, k( Y) N5 s5 O" \
set my-row -1
k; K, z" U. M& M4 p/ q* O set my-column -1
8 g" z( v( [' Y# y* [ set my-phase -16 y u1 }+ \/ @9 B, B: Q
set pcolor brown + 3
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* P- X4 N; n9 ^" ?- Y, ~ ;; initialize the global variables that hold patch agentsets4 V% w$ c. ^0 T: a" k! J
set roads patches with
8 z. z5 d6 Y1 O6 Z( Z [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or0 o$ u- R- Z# q2 k
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]
4 K/ e. N! a0 E! O7 r0 Q3 ^+ F set intersections roads with6 _% I4 S/ l, d! G3 M
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
$ k* Q9 @6 U- y3 Q8 Z5 o* l/ B (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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5 j# X9 ^( m1 u9 U: b. y ask roads [ set pcolor white ]
4 [! C+ b5 _$ Q% N& g setup-intersections% C: u; |! a5 } I
end! W) e( j4 d( p1 ^; {! W% C9 }
其中定义道路的句子,如下所示,是什么意思啊?
* c& j4 V& w/ H# o. m, {% n set roads patches with' S% N0 Y4 ^! d; A# o/ p, T# R
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
3 T3 h* S: V; Y. e6 [" D3 B7 @: b4 J& x (floor((pycor + max-pycor) mod grid-y-inc) = 0)]9 J' v4 R7 N" N x5 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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