Re: floating point representation - Mailing list pgsql-hackers

From Hiroshi Inoue
Subject Re: floating point representation
Date
Msg-id 3A90BA93.5CD919A0@tpf.co.jp
Whole thread Raw
In response to RE: floating point representation  ("Hiroshi Inoue" <Inoue@tpf.co.jp>)
List pgsql-hackers
Tom Lane wrote:
> 
> Hiroshi Inoue <Inoue@tpf.co.jp> writes:
> > The 7.1-release seems near.
> > May I provide the followings ?
> >       SET FLOAT4_PRECISION TO ..
> >       SET FLOAT8_PRECISION TO ..
> 
> > Or must we postpone to fix it ?
> 
> This seems a small enough change that I do not fear fixing it at this
> late date.  However, I do not like the idea of making the SET variables
> be just number of digits precision.  As long as we're going to have SET
> variables, let's go for the full flexibility offered by sprintf: define
> the SET variables as the sprintf format strings to use. 

Agreed.

> The defaults
> would be "%.7g" and "%.17g" (or thereabouts, not sure what number of
> digits we are currently using).

Wouldn't changing current '%.6g','%.15g'(on many platforms)
cause the regression test failure ? 

> This way, someone could select the C99
> %a format if he knew that his libc supported it.  Or he could force a
> particular format like %7.3f if that's what he needed in a specific
> application.
> 

Regards,
Hiroshi Inoue


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