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Re: Best way to represent fractional values?

• To: "Chiusano Joseph" <chiusano_joseph@b...>
• Subject: Re: Best way to represent fractional values?
• From: "Hugh Wallis" <hugh_wallis@h...>
• Date: Mon, 10 Feb 2003 14:04:11 -0500
• Cc: <xml-dev@l...>
• References: <008c01c2d12c$80f4ac80$c2941bac@h...> <3E47E909.2A3ACC71@b...> <00f101c2d130$1589e830$c2941bac@h...> <3E47F4C7.7F6FFA0B@b...>

But my point is that I can never make fractionDigits large enough to reach a
representation of 1/3 since that would require fractionDigits to equal
infinity. I want to be able to represent exactly 1/3, not some close
approximation of it.

Now I know people are going to say "you can't do that in computers because
of floating point stuff" but that isn't really true - if you represent the
numerator and denominator separately then you can represent it perfectly
fine.

A use-case for this is the representation of a tax calculation where the
legislation specifically dictates factors to be applied to other numbers
that are fractions (and often more complicated than 1/3 which I was using as
a simple example). These factors may well not be representable accurately as
decimals.

Cheers

Hugh
----- Original Message -----
From: "Chiusano Joseph" <chiusano_joseph@b...>
To: "Hugh Wallis" <hugh_wallis@h...>
Cc: <xml-dev@l...>
Sent: Monday, 10 February, 2003 1:51 PM
Subject: Re:  Best way to represent fractional values?


<Snip>
What you suggest would limit me to 0.33
</Snip>

Not at all, if you make fractionDigits greater than 2.

Hugh Wallis wrote:
>
> Thanks Joe - but I don't think that solves the problem. How do you
represent
> the value 1/3 exactly this way? What you suggest would limit me to 0.33
> which is 33/100 which does not equal 1/3
>
> Hugh
> ----- Original Message -----
> From: "Chiusano Joseph" <chiusano_joseph@b...>
> To: "Hugh Wallis" <hugh_wallis@h...>
> Cc: <xml-dev@l...>
> Sent: Monday, 10 February, 2003 1:01 PM
> Subject: Re:  Best way to represent fractional values?
>
> Hugh,
>
> W3C Schema does define facets for these:
>
> totalDigits - max # of digits in the value
> fractionDigits - max # of digits in fractional part
>
> Ex. from W3C Schema Primer [1]:
>
> <simpleType name='amount'>
>   <restriction base='decimal'>
>     <totalDigits value='8'/>
>     <fractionDigits value='2' fixed='true'/>
>   </restriction>
> </simpleType>
>
> Hope that helps,
> Joe Chiusano
> Booz | Allen | Hamilton
>
> [1] http://www.w3.org/TR/xmlschema-0/

• Follow-Ups:
  • Re: Best way to represent fractional values?
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• References:
  • Best way to represent fractional values?
    • From: "Hugh Wallis" <hugh_wallis@h...>
  • Re: Best way to represent fractional values?
    • From: "Chiusano Joseph" <chiusano_joseph@b...>
  • Re: Best way to represent fractional values?
    • From: "Hugh Wallis" <hugh_wallis@h...>
  • Re: Best way to represent fractional values?
    • From: "Chiusano Joseph" <chiusano_joseph@b...>

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