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From: Paul Rubin <no.email@nospam.invalid>
Newsgroups: comp.lang.forth
Subject: Re: real to rational number
Date: Thu, 20 Apr 2017 11:46:40 -0700
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"Rudy Velthuis" <newsgroups@rvelthuis.de> writes:
> Then I don't quite understand it. If you already have a mathematical
> real, then what is the problem?

You want to find a rational approximation to your mathematical real.
E.g. suppose your real is pi.  You could use 31/10 as an approximation,
but it turns out 22/7 is closer.  If you want even better, 355/113 is
extremely close.  How do you find these fractions?  You could do a
brute force search through possible denominators, but there's a much
faster algorithm using continued fractions that I posted.