Re: numeric precision when raising one numeric to another.

On Wed, May 18, 2005 at 10:46:50PM -0400, John Burger wrote:
> >>Considering that the SQL spec says the result of multiplication of
> >>exact
> >>numeric types is exact numeric types of precision S1+S2, and
> >>exponentiation is nothing more than repeated multiplication,
> >
> >... not when the exponent is non-integral.
>
> For one thing. For another, I believe the standard C library only has
> floating point exponentiation functions, not that there aren't plenty
> of numeric libraries with integral ones. Finally, exponentiated
> numbers get real big, real fast, and the floating point types can hold
> much larger magnitudes than the integer types, albeit inexactly. For
> example, on the Mac I'm using now, long long ints max out at about
> 10^19, while long doubles can represent 10^308.

Well, we already have an interesting library of mathematical functions
for NUMERIC (which is an arbitrary precision type, so it wouldn't matter
how big the result would get). I think the only reason we don't have a
NUMERIC exponentiation function is that nobody has implemented it.

--
Alvaro Herrera (<alvherre[a]surnet.cl>)
"People get annoyed when you try to debug them." (Larry Wall)