Re: Motion P1788.1/M004.01
On 19.05.2016 09:54, Vincent Lefevre wrote:
> BTW, what would be useful for interval arithmetic is some non-sticky
> inexact bit/flag, at least for some operations, for instance to
> convert a number literal to an interval, so that only one conversion
> is needed, the result being of the form [x,x] or [x,x+] depending on
> whether the conversion is exact or not (x+ denotes the successor of
> the machine number x). GNU MPFR provides a ternary value for each
> operation (i.e. the sign of the error), which is often used.
It is not precisely the same, but we have exactToInterval and
textToInterval operations for the distinction of exact conversion in
IEEE 1788-2015.
In GNU Octave, the interval constructors provide “is exact” and
“overflow” flags, because I also find it useful for these operations.
For arithmetic operations I don't find it very useful, since the result
will most likely be inexact after some operations.
Oliver