Thread Subject: whittaker W function

Hello all,

I want to compute Whittaker W function. In matlab docs, i see that it is possible through symbolic toolbox (or in Mupad) by using:

whittakerW(a,b,z)

However, I want a method to use this function simply in my m-file code.

Any help will be highly appreciated.

Regards,
Tom.

On 1/29/2012 11:42 PM, Ozair wrote:
> Hello all,
>
> I want to compute Whittaker W function. In matlab docs, i see that it is possible through
>symbolic toolbox (or in Mupad) by using:
>
> whittakerW(a,b,z)
>
> However, I want a method to use this function simply in my m-file code.
>
> Any help will be highly appreciated.
>
> Regards,
> Tom.


I have 2011a and I do not see that function there vecuase help does not
show it. But I see it is in 2011b

http://www.mathworks.com/help/toolbox/mupad/stdlib/whittaker.html

Now, for your question: What exactly are you asking? You want to call
this from your m file? Then what error do you get if you do?

Or do you want the actual source code of the function itself?

--Nasser

Thanks Nasser,

I just want to call this function from my m-file and want to compute the result for given numeric values of a, b and z.

I dont want the actual source code.

I am using R2010a.

regards,
Ozair.

"Nasser M. Abbasi" <nma@12000.org> wrote in message <jg5b35$l4f$1@speranza.aioe.org>...

> I have 2011a and I do not see that function there vecuase help does not
> show it. But I see it is in 2011b
>
> http://www.mathworks.com/help/toolbox/mupad/stdlib/whittaker.html
>
> Now, for your question: What exactly are you asking? You want to call
> this from your m file? Then what error do you get if you do?
>
> Or do you want the actual source code of the function itself?
>
> --Nasser

On 1/30/2012 12:01 AM, Ozair wrote:
> Thanks Nasser,
>
> I just want to call this function from my m-file and want to compute the result for given numeric
>values of a, b and z.
>
> I dont want the actual source code.
>
> I am using R2010a.
>
> regards,
> Ozair.
>

if you are using 2010a, it might be in that version, because I have
a more recent version 2011a, and when I do help on it, it does not show up.

Mathworks must have added this function in the most recent Matlab version?

------------------
EDU>> which whittakerW
'whittakerW' not found.
EDU>> help whittakerW

whittakerW not found.

EDU>> ver
MATLAB Version 7.12.0.635 (R2011a)
----------------

In this case, I am not sure how to obtain it. May be someone else
will have better advice. Trying googling around.

hth,

--Nasser

"Nasser M. Abbasi" <nma@12000.org> wrote in message <jg5gff$v4k$1@speranza.aioe.org>...

In 2010a, whittakerW() function is available in Mupad. If I open the mupad help, it shows the help on whittakerW() function too.

However, when i try to use this function in m-file using "syms" and "subs", it gives this error in workspace:

??? Undefined function or method 'whittakerW' for input arguments of type 'sym'.

So now i am stuck. Any help regarding this will be highly appreciated.

rgds,
Ozair.

> if you are using 2010a, it might be in that version, because I have
> a more recent version 2011a, and when I do help on it, it does not show up.
>
> Mathworks must have added this function in the most recent Matlab version?
>
> ------------------
> EDU>> which whittakerW
> 'whittakerW' not found.
> EDU>> help whittakerW
>
> whittakerW not found.
>
> EDU>> ver
> MATLAB Version 7.12.0.635 (R2011a)
> ----------------
>
> In this case, I am not sure how to obtain it. May be someone else
> will have better advice. Trying googling around.
>
> hth,
>
> --Nasser

On 1/30/2012 1:22 AM, Nasser M. Abbasi wrote:
> On 1/30/2012 12:01 AM, Ozair wrote:

>
> if you are using 2010a, it might be in that version, because I have

s\might be\might NOT be\

On 1/30/2012 1:51 AM, Ozair wrote:
> "Nasser M. Abbasi"<nma@12000.org> wrote in message<jg5gff$v4k$1@speranza.aioe.org>...
>
> In 2010a, whittakerW() function is available in Mupad. If I open the mupad help,

I see. I do not use that interface. I see it now on my version when I enter
mupad itself.

I use the standard Matlab interface, and never really used MuPad interface
like that. So, I'll step on the side, and let someone else help you
on this, as I am not familiar with this setup.

--Nasser

On 30.01.12 08:51, Ozair wrote:
> "Nasser M. Abbasi" <nma@12000.org> wrote in message <jg5gff$v4k$1@speranza.aioe.org>...
>
> In 2010a, whittakerW() function is available in Mupad. If I open the mupad help, it shows the help on whittakerW() function too.
>
> However, when i try to use this function in m-file using "syms" and "subs", it gives this error in workspace:

There is no MATLAB function of that name in 2010a. A non-vectorized one
is easy enough to write, though:

function w = whittakerW(a, b, z)
  w = feval(symengine, 'whittakerW', a, b, z);

Of course, depending on your application, you may want to add a DOUBLE
call, maybe something like

function w = whittakerW(a, b, z)
  w = feval(symengine, 'whittakerW', a, b, z);
  try
    w = double(w);
  catch
    % ignore, return symbolically
  end


Christopher

Thanks Christopher,

I will try this method now.

rgds,
Ozair.
Christopher Creutzig <Christopher.Creutzig@mathworks.com> wrote in message
>
> There is no MATLAB function of that name in 2010a. A non-vectorized one
> is easy enough to write, though:
>
> function w = whittakerW(a, b, z)
> w = feval(symengine, 'whittakerW', a, b, z);
>
> Of course, depending on your application, you may want to add a DOUBLE
> call, maybe something like
>
> function w = whittakerW(a, b, z)
> w = feval(symengine, 'whittakerW', a, b, z);
> try
> w = double(w);
> catch
> % ignore, return symbolically
> end
>
>
> Christopher