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Re: Motion P1788/M0032.01:MidpointMeaning -- discussion period begins



With regard to midpoint for implicit formats,
Dan Zuras wrote, replying to Vincent Lefèvre:
>> In particular, these requirements are valid for:
>>   X1 = hull_T([inf_F(X),mid_F(X)])
>>   X2 = hull_T([mid_F(X),sup_F(X)])
>> if a hull_T function is defined.
>
> Also a fair point.  Is hull any more unique
> among the implicits than the "smallest"
> superset in question?

I seem to recall that part of the *definition* of an implicit format
is an explicit hull function that is THE hull function by definition,
precisely because there may not be a unique "natural" hull.

For variable-precision formats there may indeed not be a "smallest",
at least in a practical sense.  (An item that consumes the remainder
of the address space may well be a tightest enclosure in any given
situation, but would be useless since there would be no resources to
continue with the computation.)

Michel.
---Sent: 2012-03-15 15:50:30 UTC