error in elliptic_e ?



On Tue, Nov 15, 2011 at 2:45 PM, Raymond Toy <toy.raymond at gmail.com> wrote:

>
>
> On Tue, Nov 15, 2011 at 1:59 PM, Raymond Toy <toy.raymond at gmail.com>wrote:
>
>>
>>
>> On Tue, Nov 15, 2011 at 1:11 PM, Edwin Woollett <woollett at charter.net>wrote:
>>
>>> Perhaps I am not invoking elliptic_e
>>> correctly, but it appears that the definition
>>> given in the help manual does not agree
>>> with interactive use of elliptic_e.
>>>
>>
>> Looks like a bug.  Not sure what the problem is, though.
>>
>
> It's because elliptic_e doesn't handle the quasi-periodicity of
> elliptic_e.  I think elliptic_k has the same problem.  I'll fix this soon.
>
>
Fixed in git.  Also fixed the same problem with elliptic_f.

But there's still a problem with symbolic computations.  elliptic_e(%pi,1)
returns 0.  It should return 2.  This is caused by elliptic_e(x,1)
simplifying to sin(x).  Should we return something complicated like
sin(x-%pi*round(x/%pi)) + 2*round(x/%pi)?

(I see there's also a bug:  elliptic_ec(1) should return 1 but doesn't.)

Ray