I think the crucial point is that the common IEEE floating point
formats are unable to store an EXACT representation of common
decimal fractions (such as .1) -- they can only store an
APPROXIMATION.
>>> Peter Eisentraut <peter_e@gmx.net> >>>
Csaba Nagy wrote:
> [snip]
>
> > Floating points numbers are accurate but not precise.
>
> OK, now this one beats me... what's the difference between "accurate"
> and "exact" ? I thought both mean something like "correct", but
> precise refers to some action and accurate applies to a situation or
> description...
Accurate means close to the real value, precise means having a lot of
detail.
So 3 is more accurate than 4 as a representation of "Pi", but both are
not very precise.
5.32290753057207250735 is a very precise representation of "Pi" but
totally inaccurate.
This also means that the statement at the top is wrong. It should be
the other way around.
--
Peter Eisentraut
http://developer.postgresql.org/~petere/
---------------------------(end of broadcast)---------------------------
TIP 2: Don't 'kill -9' the postmaster
