-----Original Message----- From: boost-bounces@lists.boost.org [mailto:boost-bounces@lists.boost.org] On Behalf Of David Abrahams Sent: Monday, July 26, 2010 4:51 PM To: boost@lists.boost.org Subject: Re: [boost] accurate sum accumulator (kahan)
At Mon, 26 Jul 2010 16:20:16 +0100, Paul A. Bristow wrote:
At Mon, 26 Jul 2010 14:59:29 +0100, Paul A. Bristow wrote:
PS As for naming, I'd vote for sum and accurate_sum (to keep backward compatibility).
It's possible I'm completely off the mark here, but I think maybe we want sum and quick_sum.
This would be ideal - but doesn't accumulator already use 'sum' so it would change behaviour of existing programs?
Technically, of course it would, but aren't they getting the wrong answer currently?
Yes (a bit, sometimes, probably) - but quicker ;-) (Seriously - a change in accuracy might mean that tests just fail and this might cause more trouble than it was worth. This being floating point, even the Kahan method doesn't guarantee a *exact* answer, just a more accurate one). Paul