Re: numeric and float converts to int differently? - Mailing list pgsql-sql

From SZUCS Gábor
Subject Re: numeric and float converts to int differently?
Date
Msg-id 0acb01c39d90$6d9d9080$0403a8c0@fejleszt4
Whole thread Raw
In response to numeric and float converts to int differently?  ("SZŰCS Gábor" <surrano@mailbox.hu>)
Responses Re: numeric and float converts to int differently?  (Bruno Wolff III <bruno@wolff.to>)
List pgsql-sql
----- Original Message ----- 
From: "Greg Stark" <gsstark@mit.edu>
Sent: Tuesday, October 28, 2003 7:21 PM


> > > cannot see is that the float values are not actually exactly 0.5
> >
> > Yes I could guess that (floating point vs fixed), but is this a
coincidence
> > that both '0.5'::float and '-0.5'::float are closer to 0, whereas they
could
> > be closer to +/-1, as well as both closer to the lower or upper bound.
>
> Wouldn't 0.5 and -0.5 be representable exactly as floats?

As Tom pointed out, it isn't a floating point failure -- it is how rounding
float is implemented. I assume anything with less than 15 digits can be
exactly represented as float.

G.
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