Re: factorial doc bug?

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Patrick Welche <prlw1(at)newn(dot)cam(dot)ac(dot)uk>
Cc: Peter Eisentraut <peter_e(at)gmx(dot)net>, Thomas Lockhart <lockhart(at)fourpalms(dot)org>, Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: factorial doc bug?
Date: 2001-09-12 17:28:39
Message-ID: 200109121728.f8CHSdC18478@candle.pha.pa.us
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> On Wed, Sep 12, 2001 at 02:45:10PM +0200, Peter Eisentraut wrote:
> > Thomas Lockhart writes:
> >
> > > Keep in mind that he is a mathematician, and I'll guess that he won't
> > > have much patience with folks who expect a result for a factorial of a
> > > fractional number ;)
> >
> > Real mathematicians will be perfectly happy with a factorial for a
> > fractional number, as long as it's properly and consistently defined. ;-)
> >
> > Seriously, there is a well-established definition of factorials of
> > non-integral real numbers, but the current behaviour is probably the most
> > intuitive for the vast majority of users.
>
> I would be happy with with exp(lgamma(x+1)) as a synonym for x!
> (So 4.3!=38.078 as far as I'm concerned :) )

Yes, gamms is the standard for non-integer factorial but we don't
implement it that way. :-)

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