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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。% t; S i4 Q: z( ~% A
netlogo自带的social science--traffic grid这一例子当中, [, g! m0 V% I/ N$ W& E2 J
globals* W5 b/ F3 J y$ x3 I5 F5 I/ q
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grid-x-inc ;; the amount of patches in between two roads in the x direction2 X! i- B7 }% `5 C
grid-y-inc ;; the amount of patches in between two roads in the y direction
; ^2 X' u" @. Z acceleration ;; the constant that controls how much a car speeds up or slows down by if/ b+ [2 H' O3 ~9 w/ |" j
;; it is to accelerate or decelerate0 b& J! \3 U9 f# k& \
phase ;; keeps track of the phase
7 `1 }1 w% o t/ @ num-cars-stopped ;; the number of cars that are stopped during a single pass thru the go procedure4 Q, o u0 K4 C: t5 K j( ~
current-light ;; the currently selected light; I d* S* |/ ^; b
& `7 y/ {. M/ a1 ]; s ;; patch agentsets
: v" k, z& W2 f* b+ ^$ w3 S intersections ;; agentset containing the patches that are intersections% ?9 C! I9 p' Y [8 z( |) F
roads ;; agentset containing the patches that are roads
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1 d2 ]6 E" w. o4 G3 i, W: sturtles-own
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speed ;; the speed of the turtle# k- i: n1 A" o4 M
up-car? ;; true if the turtle moves downwards and false if it moves to the right7 l7 `- F; S1 @
wait-time ;; the amount of time since the last time a turtle has moved" n% |; |6 z5 c9 W+ B
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& L. x9 Z+ N# Opatches-own5 \" g! I) K' F4 g* O2 x( \
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intersection? ;; true if the patch is at the intersection of two roads# O* Y' u4 K; e. Y
green-light-up? ;; true if the green light is above the intersection. otherwise, false.
) O0 z" p$ m9 H6 C% m; f' |) G: ~ ;; false for a non-intersection patches.
" @8 W* w, a2 M0 c9 e my-row ;; the row of the intersection counting from the upper left corner of the
9 }# l( @3 E6 u: f1 t/ _ ;; world. -1 for non-intersection patches.* ]1 z8 m( l+ S8 C. u
my-column ;; the column of the intersection counting from the upper left corner of the
; R- A3 U' v! E/ U, } ;; world. -1 for non-intersection patches.& b. X8 h1 r/ k
my-phase ;; the phase for the intersection. -1 for non-intersection patches.
) c" l4 I# h# k- w- | auto? ;; whether or not this intersection will switch automatically.
+ x8 e8 I; V5 X ;; false for non-intersection patches.
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+ E& V4 B' r5 x' ?. l+ O& a0 [9 R% b;;;;;;;;;;;;;;;;;;;;;;0 ^) M- D7 X6 q- |8 Z/ F
;; Setup Procedures ;;4 I( j# x0 U$ K+ H* v/ c, F4 X
;;;;;;;;;;;;;;;;;;;;;;
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' c# c; t& ?) d2 g7 M" @;; Initialize the display by giving the global and patch variables initial values.
3 t S# C- u: Z( ]# o1 V;; Create num-cars of turtles if there are enough road patches for one turtle to
$ o. k3 K! Z- E7 {. H;; be created per road patch. Set up the plots., q0 }* ^3 L4 H7 n3 [3 E; ]2 ^/ y
to setup
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9 n. E& A; [* O# Z' C setup-globals' _% {3 k+ y9 k( F h* B _
- d$ {9 c+ x' p+ w, f ;; First we ask the patches to draw themselves and set up a few variables" p' l& r9 m( y$ \
setup-patches
5 a* M; a3 `4 z, d3 _3 z make-current one-of intersections
& j" K' V+ Y2 t; N7 b3 o label-current
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4 T. e$ X* I7 r) F5 D$ H set-default-shape turtles "car"' `2 H& j6 n9 _- U9 d) V. T# ~! E+ ^% A
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if (num-cars > count roads)9 q. z2 z! T5 u% m
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user-message (word "There are too many cars for the amount of "4 G e7 M2 Q+ g. v& T
"road. Either increase the amount of roads "- h: x0 o5 [! B$ ?$ j
"by increasing the GRID-SIZE-X or "
% k/ T; h# N7 ?& ~6 p. q1 }6 M5 Z3 e "GRID-SIZE-Y sliders, or decrease the "
: Y/ \+ v: ]2 A! z$ y "number of cars by lowering the NUMBER slider.\n"# I* ], q& ]$ |$ t" |* f) I' r
"The setup has stopped.")+ j- a5 r6 |6 O' H& u
stop
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- x' _+ e4 X+ x0 t/ j9 I ;; Now create the turtles and have each created turtle call the functions setup-cars and set-car-color
8 U( I4 Q. G4 N9 z7 u; ? crt num-cars) @+ M T. M3 g9 ?! o, \0 x2 a2 d
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setup-cars
" X( B0 G8 H! D: i" i$ A+ O! \; V0 P set-car-color
4 D {2 r0 s1 G% }! Y record-data" r4 p5 f0 H# a# S: G/ I: u
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;; give the turtles an initial speed
4 ^$ }; z6 ?/ h: r$ V; J1 f ask turtles [ set-car-speed ]
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: R, K8 G- w0 Z3 R, \7 |- x" ^ reset-ticks N2 `9 H6 B: F* I- m3 R. Z( A
end
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;; Initialize the global variables to appropriate values
# T0 w' A9 u- Y0 W1 p$ Oto setup-globals
+ P) l2 H- e2 E, z8 t/ V set current-light nobody ;; just for now, since there are no lights yet+ U* K, U1 @+ j% Z4 U
set phase 0# E) G$ | f9 l4 [* Q/ g
set num-cars-stopped 0! V- b9 |- H2 B- L" V
set grid-x-inc world-width / grid-size-x8 e. y9 ]4 c; n0 ?+ c" e/ j# Y4 ^
set grid-y-inc world-height / grid-size-y
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0 T( M e) @$ ~4 B& A. f3 V ;; don't make acceleration 0.1 since we could get a rounding error and end up on a patch boundary" l, w& s8 b; l1 W+ b: }- M; A
set acceleration 0.099
- B" L0 P4 O: G4 m7 ^end
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;; Make the patches have appropriate colors, set up the roads and intersections agentsets,
9 K8 K. c# Y6 u' y# Y;; and initialize the traffic lights to one setting
: x" ~0 `: I5 @ o% Hto setup-patches+ n. f7 e+ F* Q# H7 T9 _- a- r
;; initialize the patch-owned variables and color the patches to a base-color& W( R$ o2 W# t2 ?1 v- q! n! _) o
ask patches. M- e! V9 H; F: J% E1 V
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T. I9 L; g6 E$ B6 C) m' q2 J set intersection? false
2 }) p# f$ c1 L3 F- F1 x/ i set auto? false' q+ C8 J# B) d& ^$ `% b9 [
set green-light-up? true
& J5 T+ P) g; A1 n set my-row -1" t. n/ N* [, b% ]5 f
set my-column -1) N( ?& v+ R7 m$ A. E$ D: w" X. t
set my-phase -1
8 m, e3 L0 D/ i6 P set pcolor brown + 3
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9 |8 M; V/ D. N" ` ;; initialize the global variables that hold patch agentsets# u6 i' b0 P1 K U" e' O2 w
set roads patches with& n: v/ L1 x. f7 [3 v% d! X# K: W
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or1 |. l- ?# Y& i+ ~" `3 u
(floor((pycor + max-pycor) mod grid-y-inc) = 0)]; `- }; m7 N# K
set intersections roads with! e! n$ E9 ~+ u
[(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) and
; t2 |( i: P {0 r, R* M (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
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7 P) o) B2 a$ H% s ask roads [ set pcolor white ]
x+ V) n4 F- [% } setup-intersections( B1 \& Y& U' K) b M
end
& t H% j' {0 u; S% I/ C其中定义道路的句子,如下所示,是什么意思啊?( n4 N. E. _) _: O6 a
set roads patches with
. L/ I1 @, a; M" W+ [1 P) d7 u, i [(floor((pxcor + max-pxcor - floor(grid-x-inc - 1)) mod grid-x-inc) = 0) or
8 p7 ?) B: v; i) U3 Y# j9 A (floor((pycor + max-pycor) mod grid-y-inc) = 0)]
. U1 O5 u; q0 m- C6 [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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