Fun with roundoff error

linas@linas.org linas@linas.org
Thu, 7 Dec 2000 17:14:53 -0600 (CST)


It's been rumoured that Randolph Fritz said:
> 
> On Tue, Dec 05, 2000 at 03:08:53PM -0600, Bill Gribble wrote:
> > 
> > Each value has a denominator, and each account specifies the
> > denominator in which it represents its credit/debit amounts.  If a
> > financial institution represents your balance to the nearest USD
> > 1/100, any additions or subtractions to that account must be in USD
> > 1/100.
> 
> As far as I know, major US banks uniformly use 1/10,000 as the
> denominator, by the way.  I consulted an old friend who used to
> consult for the NYC banks on this some months back.

I think there's two quasi-related issues.
-- the smallest amount of money you can >>>transfer<<< is a penny.
   We don't have half-cent coins in the US, and you can't write checks
   or wire transfers for fractional pennies.

-- the >>arithmetic<< used inside of gnucash must be 'correct'.

Since most of what gnucash does is record transfers, the first rule 
applies.