Re: numeric precision when raising one numeric to another. - Mailing list pgsql-general

From John Burger
Subject Re: numeric precision when raising one numeric to another.
Date
Msg-id f7dbed2cc9c8db8cb2cbfbcf546a38b7@mitre.org
Whole thread Raw
In response to Re: numeric precision when raising one numeric to another.  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: numeric precision when raising one numeric to another.
List pgsql-general
>> 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.

- John Burger
   MITRE



pgsql-general by date:

Previous
From: Michael Glaesemann
Date:
Subject: Re: 8.0.3 build error on Mac OS X 10.4
Next
From: Tom Lane
Date:
Subject: Re: 8.0.3 build error on Mac OS X 10.4