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From: "Roger Stafford" <ellieandrogerxyzzy@mindspring.com.invalid>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Intersect circle and irregular shape
Date: Wed, 9 Jan 2008 20:32:02 +0000 (UTC)
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"Charles Cuell" <cuell@math.usask.ca> wrote in message <fm36sq$2m2
$1@fred.mathworks.com>...
> I would just go for coffee, or lunch, or a vacation :)
> Point taken, anyway.
> Charles
--------
  It would be a very long coffee break, Charles, if GL were to attempt to 
extract all the accuracy out of his computations that matlab's double 
precision is capable of, using the 10^k method.  It would require something 
of the order of 10^16 divisions of the full circle and therefore a like number 
of calls on inpolygon to achieve that.  That way I figure he might have his 
computer occupied for several hundred years on each circle.  With the web 
example GL showed, there would only be four calls on inpolygon and six calls 
on roots with the intersection method.  It seems to me a better practice, both 
from a computation efficiency point of view, and from an esthetic one too, to 
find all the intersections between the circle and the polygon precisely and 
work from there.  The computations should all be accurate to the full one part 
in 10^16 that way.

Roger Stafford