Re: [GENERAL] rounding problems

On Tue, May 13, 2008 at 02:36:18PM -0400, Justin wrote:
> Double holds 15 places which is the highest value of precision it can
> maintain before rounding occurs.
>
> Is is limit less no, but what is?
>
> Practically speaking taking a vale 0.000,000,000,000,001 aka
> 1 trillionth of anything,

But remember that if you add this value onto a large number and then
take off the large number the result will be zero.

(0.000,000,000,01 + 1,000,000) - 1,000,000 ==> 0
0.000,000,000,01 + (1,000,000 - 1,000,000) ==> 0.000,000,000,01

In general, operations on floating point numbers will increase their
errors.

> i view the problem solved for 98% of problems.

Floating point math is good for most problems, hence why most languages
expose the abstraction.

Sam

--
Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general