[Cfp-interest 2114] Re: AI about updating definition of normalized

[Jim Thomas]

> On Aug 21, 2021, at 2:51 PM, Fred J. Tydeman <tydeman at tybor.com> wrote:
> 
> On Sat, 21 Aug 2021 14:43:45 -0700 Jim Thomas wrote:
>> 
>> Please send any issues by end of noon Tuesday, August 24.
> 
> Should "zero (all fk = 0)" be "zero(all fp = 0)"?

All fk = 0 says all the significand digits are 0, which is what we want. All fp = 0 would indicate numbers whose least significant digit is 0. That’s my reading.
> 
> So, these changes keep some finite double-double values as
> floating-point(FP) numbers and some as not FP numbers.
> Is that what we want?

The model defines floating-point numbers as having a fixed precision p and requires the type to include all normalized model numbers with precision p. For double-double I think that means the precision is p = 106 (it could be taken to be less than 106, but to what advantage?), and numbers represented with extra precision (and some other representations e.g. (DBL_MAX, DBL_MAX)) are not  floating-point numbers. 

- Jim Thomas

> 
> 
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> Fred J. Tydeman        Tydeman Consulting
> tydeman at tybor.com      Testing, numerics, programming
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