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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Lists: | pgsql-hackers |
> 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. :-)
--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
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