Re: A mid-rad interchange motion...

[Arnold Neumaier <Arnold.Neumaier@xxxxxxxxxxxx>]

Ralph Baker Kearfott wrote:


>> Actually, one should think of "mid-rad1-rad2" as center+error-interval,
>> thus it is composed of two objects, a center and an error interval,
>> possibly of different precisions.
>

> This is somewhat reminiscent of the staggered arithmetic techniques
> used, for example, to achieve rapid, "almost accurate" dot products
> in software with 754 numbers.  Is that the underlying sense (that is, 
> roughly, to use
> two floating point datums, or possibly two datums with
> different precisions) to represent the radius?

Yes, this is essentially staggered correction, in that staggered 
correction interval techniques use an interval to represent the error.
However, staggered correction simulates multiprecision by a sum of 
floats, which is somewhat inefficient compared to true multiprecision 
arithmetic.