Using matfile objects as input parameters

I was wondering if a matfile object can be used as an input parameter for any matlab function, like in the following example:

distances = matfile(output_file,'Writable',true);
distances.D = zeros(1,N*(N-1)/2);
%Compute distances and store them in distances.D

% Applying multidimensional scaling to the distances matrix
[Y,eigvals] = cmdscale(D);

Is that possible? What about operators like distances.D*distances.D? Or should I reimplement matlab functions and operators again if I am using this kind of objects?

Answer 1

[per isakson]

Yes, it is ok to pass around matfile objects, matObj; make some simple experiments.

I don't think the documentation says anything about several different matObj, which refer to the same file at the same time.

[Pablo]

Thank you for your answer.

What if the invoked method (like cmdscale in my example) has to return a huge array? Let's suppose that there is not enough space in memory for that returned array. Is it any way to make it use matfile objects?

[per isakson]

Speculation: There should be "no difference" between

    distances.D = zeros(1,N*(N-1)/2);

and

    [ matObj.Y, eigvals ] = cmdscale(D);

Make an experiment to find out how smart matfile is with large variables.