On Thu, 2 Oct 2003, Nicholas Clark wrote:
> On Thu, Oct 02, 2003 at 10:35:29AM +0200, Leopold Toetsch wrote:
> > Adam Thomason <[EMAIL PROTECTED]> wrote:
>
> > > The one remaining test failure in 'make test' is op/number test 10,
> > > the second part of which computes mod(0.0,3.0). The expected value is
> > > 0.0, but I see -0.0. However, given the definition of
> > > mod(x,y)=x-y*floor(x/y), this case reduces to 0.0-0.0*0.0, which could
> > > justify -0.0. Perhaps the test can be relaxed somehow to accomodate
> > > minus-zero semantics.
> >
> > Sounds correct, yes.
>
> Relaxing that test doesn't feel right to me. Partly in black box terms
> because I would expect putting strictly non-negative values into mod
> shouldn't create a negative zero, and partly in terms of that implementation
> because I thought that negative zero was only allowed to arise as the result
> of division and multiplication, never from addition or *in this case)
> subtraction.
In this case, while I think it's truly bizarre (negative zero, that is),
since 0 and -0 are exactly equivalent, arguably they're both OK, and thus
should both be accepted.
Dan
