Handles returning multiple outputs

Question

Lukas 2013-11-24

评论： Lukas 2013-11-24

I have a function handle that returns 3 values.

 @f(x,y) = basis_handle(x,y);
 [z, dx, dy] = f(0.1,0.1) %returns 3 vectors

what I'd like to do now is create a function handle that performs a dot product of each of those 3 vectors with another vector. Something like:

@f_2(x,y) c'*f(x,y) %c is a known vector, same size as ones returned by @f(x,y)

As it is, this handle returns only 1 value, even if I try to ask for more, i.e. this produces an error:

[z, dx, dy] = f_2(0.1,0.1)

Is there any way to create a function handle that returns all 3 values as requested?

Answer 1

Alfonso Nieto-Castanon 2013-11-24

I do not see how to do this using purely anonymous functions, but if that is not a requirement you could simply create a new function like:

 function varargout=fevalndot(c,varargin)
 [x{1:nargout}]=feval(varargin{:});
 varargout=cellfun(@(x)c'*x,x,'uni',0);
 end

and then simply define a handle to this function:

f_2 = @(x,y)fevalndot(c,f,x,y);

Lukas 2013-11-24

That's exactly what I ended up doing. It's a bit less slick, but it works well enough.