Re: Numeric version of factorial()

On Thu, 31 Jul 2003, Tom Lane wrote:

> Gavin Sherry <swm@linuxworld.com.au> writes:
> > 2) since we're accepting numeric arguments, the patch tests for floats. If
> > a numeric is passed with non-zero decimal portion, an error is raised
> > since (from memory) they are undefined.
>
> There is a standard mathematical definition for it (gamma function,
> IIRC) but this is probably plenty good enough for our purposes.  I would
> suggest though that you reject fractions before you short-circuit for
> x <= 1.

Oops.

>
> > 3) I have not removed factorial([int2|int4|int8]), not their operator
> > counterparts since I didn't know what people would want done with these.
>
> We had already decided to nuke the int2 and int4 versions, since they
> overflow far too easily.  I'd go with nuking int8 too and providing only
> the numeric variant ...

What are your feelings about numeric argument vs. int4/int8 arguments?

>
> > +     int8_to_numericvar((int64)1, &one);
> > +
> > +     ret = cmp_var(&fact, &one);
>
> Uh, why not use const_one?

Umm.. didn't notice it :-).

Thanks,

Gavin