- From: Kjetil Torgrim Homme <kjetilho ifi uio no>
- To: gnumeric-list gnome org
- Subject: Re: Rounding??
- Date: 14 Jun 2001 00:40:57 +0200
On Tue, Jun 12, 2001 at 09:18:03PM +0200, Kjetil Torgrim Homme wrote:
> Correct rounding is difficult. If a value falls exactly between the
> two candidates, it should choose the candidate which is _even_.
I always thought than even given that 5 is equal distance from
either 0 or 10, that it was conventional to round up.
Yes, it's conventional, but it introduces a bias. Adding up the rounded
numbers should ideally give the same result as rounding the sum of the
0.5 + 1.5 + 2.5 + 3.5 == 8
0 + 2 + 2 + 4 == 8
1 + 2 + 3 + 4 == 10
The "round towards even" algorithm can perform as bad as "round up",
but never worse, and usually much better.
] [Thread Prev