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Constrained random points on a circle: Difference between revisions
Constrained random points on a circle (view source)
Revision as of 15:10, 30 March 2020
, 4 years ago→{{header|Tcl}}: + Standard ML
m (→version 1: simplified the code, optimized, changed the plot character.) |
(→{{header|Tcl}}: + Standard ML) |
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</pre>
=={{header|Standard ML}}==
Works with PolyML. Plotting function from 'Draw a pixel' task. Uniform random generator: copy from Random_numbers#Standard_ML. x,y plotted scaled x 10 px
<lang Standard ML>open XWindows ;
open Motif ;
val plotWindow = fn coords => (* input list of int*int within 'dim' *)
let
val dim = {tw=325,th=325} ;
val shell = XtAppInitialise "" "demo" "top" [] [ XmNwidth (#tw dim), XmNheight (#th dim) ] ; (* single call only *)
val main = XmCreateMainWindow shell "main" [ XmNmappedWhenManaged true ] ;
val canvas = XmCreateDrawingArea main "drawarea" [ XmNwidth (#tw dim), XmNheight (#th dim) ] ;
val usegc = DefaultGC (XtDisplay canvas) ;
val put = fn (w,s,t)=> (
XSetForeground usegc 0xfffffff ;
XFillRectangle (XtWindow canvas) usegc (Area{x=0,y=0,w = #tw dim, h= #th dim}) ;
XSetForeground usegc 0 ;
XDrawPoints (XtWindow canvas) usegc ( List.map (fn (x,y)=>XPoint {x=x,y=y}) coords ) CoordModeOrigin ;
t )
in
(
XtSetCallbacks canvas [ (XmNexposeCallback , put) ] XmNarmCallback ;
XtManageChild canvas ;
XtManageChild main ;
XtRealizeWidget shell
)
end;
val urandomlist = fn seed => fn n =>
(* put code from (www.rosettacode.org) wiki/Random_numbers#Standard_ML 'urandomlist' here
input : seed and number of drawings *)
end;
val normalizedPts = fn () => (* select ([0,1]*[0,1]) points in normalized bandwidth *)
let
val realseeds = ( 972.1 , 10009.3 ) ;
val usum = fn (u,v) => u*(u-1.0) + v*(v-1.0) ;
val lim = ( ~350.0/900.0, ~225.0/900.0 ) ; (* limits to usum *)
val select = fn i as (x,y) => usum i <= #2 lim andalso usum i >= #1 lim ; (* select according to inequalities *)
val uv = ListPair.zip ( urandomlist (#1 realseeds) 2500 , urandomlist (#2 realseeds) 2500 ) (* draw 2500 couples *)
in
List.take ( List.filter select uv , 1000 )
end ;</lang>
call
> val scaledXY = map (fn (x,y)=>
( Real.toInt IEEEReal.TO_NEAREST (10.0+300.0*x), Real.toInt IEEEReal.TO_NEAREST (10.0+300.0*y) )) (normalizedPts ()) ;
> plotWindow scaledXY ;
=={{header|Tcl}}==
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