Re: Arguments out?

[Paul Kienzle]

Nothing a little testing before posting won't fix ;-)

The biggest problem was not using brackets in
"function [varargout]".  I'm not sure if this is an octave bug.

The second problem was not using a cell array for case 0,1.

Try this:

function [varargout] = test (x, y, z)
  switch nargout
    case {0, 1}
      varargout = {z};

    case 2
      varargout = {z, x};

    case 3
      varargout = {z, y, x};

    otherwise
      usage ("oops");

  endswitch;
endfunction


Paul Kienzle
address@hidden


On Dec 12, 2003, at 10:03 AM, Vic Norton wrote:

> Hi Paul,
>
> The second method would work, but the first one is rather confusing. 
> For example I tried
>
> function varargout = test(x, y, z)
>         switch nargout
>                 case {0,1} varargout = z;
>                 case 2, varargout = { z, x };
>                 case 3, varargout = { z, y, x };
>                 otherwise, usage("z = test(x, y, z) or ...");
>         endswitch
> endfunction
>
> on three matrices, A, B, and C, of different sizes. Here is what came 
> out
>
> test(A, B, C)  returned ans = C
> z = test(A, B, C)  returned z = C
>
> OK so far, but
>
> [z, x] = test(A, B, C) returned
>
>    z =
>    {
>      [1,1] = C
>
>      [1,2] = A
>    }
>
> and the message
>
>    error: element number 2 undefined in return list
>
> For my application I think I just going to leave things in the order
>
>    function  [x, pi, fail] = simp(A, b, c, I)
>
> Then the function will naturally produce
>
>    a solution
>    a solution and the dual multiplier
>    a solution, the dual multiplier, and failure information
>
> depending on nargout.
>
> Thanks for your comments!
>
> Regards,
>
> Vic
>
> At 9:31 PM -0500 12/11/03, Paul Kienzle wrote:
> > So write it using varargout:
> >
> > function varargout = svd(A)
> >     ...
> >     switch nargout
> >       {0,1}, varargout = { diag(s) };
> >       3, varargout = { u, s, v };
> >       otherwise, usage("sigma=svd(A) or [u,s,v]=svd(A)");
> >    end
> > end
> >
> > or equivalently using meaningless placeholders
> > for the returned values:
> >
> > function [r1,r2,r3] = mysvd(A)
> >   ...
> >   if nargout<=1, r1=diag(s);
> >   else r1=u; r2=s; r3=v; end
> > end
> >
> > Paul Kienzle
> > address@hidden



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