Re: [HACKERS] Upgrades for 6.4.1

On Sat, 19 Dec 1998, Thomas G. Lockhart wrote:

> Date: Sat, 19 Dec 1998 02:58:32 +0000
> From: "Thomas G. Lockhart" <lockhart(at)alumni(dot)caltech(dot)edu>
> To: Jan Wieck <jwieck(at)debis(dot)com>
> Cc: hannu(at)trust(dot)ee, maillist(at)candle(dot)pha(dot)pa(dot)us, hackers(at)postgreSQL(dot)org
> Subject: Re: [HACKERS] Upgrades for 6.4.1
>
> > Easy - and the type coersion stuff helps alot!
> > Up to now (1.5 hours hacking) I have a NUMERIC type that
> > handles '+' completely, including overflow checks and
> > rounding.
>
> Neat. I was poking around waiting on a freeware extended-precision
> numerical package, but hadn't found anything with a BSD-style license.

Did you try search SAL ( Sci. Application for Linux) ?
I just did search for 'precision' and found abot 12 items. Don't know
about license bit some of them like
<a href="http://www.hut.fi/~mtommila/apfloat/">apfloat - A C++ High Performance
Arbitrary Precision Arithmetic Package</a> are freeware.
>From web page:
Apfloat is a high performance arbitrary precision package. That means you can do calculations involving
millions of digits with it. It uses Number Theoretic Transforms . It's simple to use. It's fast. It's freeware.

>
> > Another tricky part I expect when telling the parser that a
> > literal NUMERIC must not be enclosed into single quotes.
>
> This is probably the worst part, since you would hate to take the hit
> representing everything as extended precision even if the actual range
> is int4/float8. Perhaps we can read as those, but if we get a failure
> then escalate to your extended precision type(s). The automatic type
> conversion stuff should convert later if necessary, so it might be
> transparent and relatively fast.
>
> > The only ugly thing is, that I needed to put the precision
> > AND the scale together into atttypmod (I limited both to 99
> > for now and put them as prec<<8 | scale into). So pg_dump
> > will need attention later.
>
> As Bruce points out, that was anticipated (but I agree it's ugly). Shift
> over 16 bits if you want...
>
> Congrats!
>
> - Tom
>

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