From: Michael Rys <mrys@microsoft.com>

Date: Mon, 5 Apr 2004 11:16:50 -0700

Message-ID: <EB0A327048144442AFB15FCE18DC96C702859EDC@RED-MSG-31.redmond.corp.microsoft.com>

To: "Jeni Tennison" <jeni@jenitennison.com>, "Michael Kay" <mhk@mhk.me.uk>

Cc: <public-qt-comments@w3.org>, <jkenton@datapower.com>

Date: Mon, 5 Apr 2004 11:16:50 -0700

Message-ID: <EB0A327048144442AFB15FCE18DC96C702859EDC@RED-MSG-31.redmond.corp.microsoft.com>

To: "Jeni Tennison" <jeni@jenitennison.com>, "Michael Kay" <mhk@mhk.me.uk>

Cc: <public-qt-comments@w3.org>, <jkenton@datapower.com>

I don't think deciding precision based on instance information is acceptable. Many type systems have precision (and scale) as a type facet that should be determined based on the arguments. Also, I am not yet convinced that anything stricter than implementation-defined will be acceptable given the wide range of implementation platforms... Best regards Michael > -----Original Message----- > From: public-qt-comments-request@w3.org [mailto:public-qt-comments- > request@w3.org] On Behalf Of Jeni Tennison > Sent: Monday, April 05, 2004 2:20 AM > To: Michael Kay > Cc: public-qt-comments@w3.org; jkenton@datapower.com > Subject: Re: Question about decimal arithmetic > > > Hi Mike, > > > I would like to offer the following suggestion for a more > > interoperable definition of decimal division: > > > > If the types of $arg1 and $arg2 are xs:integer or xs:decimal, then > > the result is of type xs:decimal. The precision of the result is > > implementation-defined, but it must be not be less than min((18, > > max((p1, p2)), R)) digits, where p1 is the precision of $arg1, p2 is > > the precision of $arg2, and R is the number of digits (possibly > > infinite) required to represent the exact mathematical result. > > "Precision" here means the total number of significant decimal > > digits in the value; all digits are considered significant other > > than leading zeros before the decimal point and trailing zeros after > > the decimal point. If rounding is necessary, the value must be > > rounded towards zero. Handling of overflow and underflow is defined > > in section 6.2. > > Using the precision of the two arguments to determine the precision of > the result leads to results that I find strange. For example: > > 1 div 3 => 0.3 > 1000000 div 3000000 => 0.3333333 > 0.00001 div 0.00003 => 0.33333 > > It would make a lot more sense to me to just use min((18, R)), but any > definition here is better than none. What cases were you thinking of > that led you to suggest using the precision of the arguments to > determine the precision of the result? > > Cheers, > > Jeni > > --- > Jeni Tennison > http://www.jenitennison.com/Received on Monday, 5 April 2004 14:17:25 UTC

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