Porposal: Floating-Point Options

[Robert Dewar]

Russell Shaw wrote:

> The original bug was about testing the equality of doubles. I think that's
> just plain mathematically bad. Error bands should be used to test for
> "equality", using a band that is in accordance with the minimum precision
> specified in the compiler documentation.

That's often taught, but in fact there are many IEEE algorithms where it
makes perfectly good sense to test for absolute equality.
> 
> OTOH, maybe the equality operators should discard the excess precision, so
> effectively implementing the error band anyway. Can't say more without 
> reading
> the relevant standards. If the equality operators did this, then it 
> shouldn't
> slow down any non-equality operators or anything else.

But it would, quite unnecessarily, slow down equality.