[ChangeSet] Beta function...

[David Bateman]

Ben Abbott wrote:
>
> On Mar 18, 2008, at 6:37 AM, David Bateman wrote:
>
>> Ben Abbott wrote:
>>>
>>> On Mar 17, 2008, at 3:40 PM, Ben Abbott wrote:
>>>
>>>> On Monday, March 17, 2008, at 02:56PM, "Jorge Londoño"
>>>> <jmlon at yahoo.com> wrote:
>>>>> I just happen to jump into a problem that require me to compute the
>>>>> Beta function with negative arguments.
>>>>> If you look at the definition of the beta function, for example here:
>>>>
>>>
>>> I replaced gammaln(x) with log(gamma(x)), modified the help text to
>>> reflect that inputs must be real, and added a few extra tests.
>>>
>>> Ben
>>
>> Is that the right (TM) thing to do, as Marco says it increases the risk
>> of overflows? Shouldn't we rather get lgamma to work correctly for
>> negative arguments. What about something like the attached patch
>> instead?
>>
>> D.
>>
>
> I agree that changing lgamma is more proper!
>
> Thanks
> Ben
The attached version might be better as the reason I used the function
name xclgamma was that I was trying to have a function like

extern Complex xclgamma (double);

but that is not possible to use within the current mapper framework.. If
the input argument is complex, then I can keep the xlgamma name for the
function..

D.


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David Bateman                                David.Bateman at motorola.com
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