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Date: Wed, 13 Dec 2006 21:13:21 +0100
From: Gautier <gautier@fakeaddress.nil>
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Subject: Re: Comparing Floating Point Values
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Date: 2006-12-13T21:13:21+01:00
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markp wrote:

> I was wondering if there was a convention for comparing 2 floats
> dealing with significant digits. For example, if I had 2 variables (x
> and y) and wanted to see if they were equal in an if statement, is
> there a standard way to do a compare based on "x" significant digits?
> 
> Thank you.

Probably you are looking at something like abs(x-y) < 10**(-n)
where n is your amount of digits (not "x" !).
This is an absolute test, you may rather be interested by a relative one.

BTW, it's worth to take a look at...
Ada 95 Quality and Style Guide, 7.2.7:
http://www.adaic.com/docs/95style/html/sec_7/7-2-7.html

HTH
______________________________________________________________
Gautier         -- http://www.mysunrise.ch/users/gdm/index.htm
Ada programming -- http://www.mysunrise.ch/users/gdm/gsoft.htm

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