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1989-10-24
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From albanycs!leah:rsb584 Wed Apr 6 17:31:10 1988
Received: by albanycs.albany.edu (5.54/4.8)
id AA28062; Wed, 6 Apr 88 11:55:28 EST
Date: Wed, 6 Apr 88 12:55:21 EDT
From: albanycs!leah:rsb584 (Raymond S Brand)
Received: by leah.Albany.EDU (5.58/1.1)
id AA02143; Wed, 6 Apr 88 12:55:21 EDT
Message-Id: <8804061655.AA02143@leah.Albany.EDU>
To: albanycs:beowulf!rsbx
Subject: circle.txt
>From roy@phri.UUCP Fri Apr 1 10:37:17 1988
Path: leah!uwmcsd1!bbn!rochester!cornell!uw-beaver!mit-eddie!husc6!cmcl2!phri!roy
From: roy@phri.UUCP (Roy Smith)
Newsgroups: comp.graphics
Subject: Re: Algorithm wanted: Circle enclosing points
Message-ID: <3226@phri.UUCP>
Date: 1 Apr 88 15:37:17 GMT
References: <wWIfSMy00Xo3A5u1dC@andrew.cmu.edu>
Reply-To: roy@phri.UUCP (Roy Smith)
Organization: Public Health Research Inst. (NY, NY)
Lines: 24
mp1u+@andrew.cmu.edu (Michael Portuesi) writes:
> I am looking for an efficient algorithm that, given a set of points, finds
> the smallest circle enclosing them and its center.
Take a look at:
%A R. Sedgewick
%T Algorithms
%D 1983
%I Addison-Wesley
%C Reading, Mass.
Chapter 25 (Finding the Convex Hull) is devoted to the problem of finding
the smallest convex polygon which encloses a set of points (in a plane,
which I assume is what you're talking about). Once you have that, it seems
intuitively obvious (i.e. I havn't actually sat down to prove it) that
you've at least narrowed the problem down a lot. For example, at least 2
of the verticies of the convex hull must lie on the circle (consider 3
points which form an equilateral triangle; all three lie on the circle).
Hope this helps.
--
Roy Smith, {allegra,cmcl2,philabs}!phri!roy
System Administrator, Public Health Research Institute
455 First Avenue, New York, NY 10016