Re: [xsl] Rounding errors in financial app transforms

[Abel Braaksma <abel.online@xxxxxxxxx>]

Hi Justin,

I've to pointers that I am thinking of, but I don't know if this is what 
you're after: Have you considered using xs:decimal? Just as an example:

xs:float(10.1) - xs:float(9.93) = 0.17000008
xs:double(10.1) - xs:double(9.93) = 0.16999999999999993
xs:decimal(10.1) - xs:decimal(9.93) = 0.17

Ok, this is just a simple example. Rounding errors can occur in a number 
of ways and I am not aware of your application and how that is normally 
done. But then, still, how about the added functionality for rounding in 
XSLT 2.0? Like: fn:round-half-to-even()?

Cheers,
-- Abel Braaksma



Justin Johansson wrote:
> What's the recommended recipe to avoid rounding-error discrepancies
> in financial applications based upon XSLT (2.0) transforms?
>
> Having demonstrated a proof-of-concept for an application based on XSLT 2.0
> to a commercial finance/accounting industry client (to replace a legacy system
> which happens to be written in CBASIC-86), a stumbling block / annoyance is
> the
> accumulation of one cent errors in the aggregated results.
>
> This, of course, is as a result of using floating-point arithmetic in XSLT.
>
> BCD arithmetic is apparently still used in mainframe applications, as was in
> CBASIC-86, but most latter-day languages including XSLT seem to have
> ignored it.
>
> Does this means that one needs to resort to doing non-trivial financial
> apps in XSLT
> in integer arithmetic?
>
> My guess is that even having a standard MulDiv function in XSLT would help
> matters floating-point-wise but sadly there is no such animal available.
>
> Thanks to all for suggestions.
>
> Justin Johansson
>
> *** A horse with no name is called Lambda ***