Tightest representable interval in mid-rad (cf. Motion 16)
Vincent Lefèvre wrote:
> "the tightest representable interval in the target type"
> is not defined in case of mid-rad and mid-rad1-rad2.
Is there a problem in defining a tie-breaking rule? The cases where
it applies are pretty rare (intervals of width 1 ulp), and one could
decide that the midpoint have an even significand, for example. Or
there could be a formula, e.g. as provided in the Vienna proposal,
where the rounding applied to the division by two would decide.
(Actually, an odd significand might be better, because in the case of
the inf-sup interval [0, MinSubnormal] the sign could be preserved.)
For mid-rad1-rad2 we don't have a precise definition on the table, so
that point is moot. Motion 16 simply says what properties are needed.
We will eventually have to settle these details, but I don't think that
was the intent of Motion 16.
Michel.
---Sent: 2010-06-28 01:07:28 UTC