Array of ClassificationTree objects

I am very new to MATLAB. I was trying to train some ClassificationTree's and the assign them in array with the following snippet

for k = 1:rows
     tree=ClassificationTree.fit(data(1:k, 1:cols),labels(1:k));
     ensemble(k)=tree;
end

however when I run this I get following error

??? Error using ==> DisallowVectorOps>DisallowVectorOps.subsasgn at 28
You cannot assign to an object of class double using () indexing.

Error in ==> dwm02 at 7
ensemble(k)=tree;

is there any way of doing this? MATLAB help on object arrays is a bit confusing..

[Walter Roberson]

How did you initialize "ensemble" ?

Answer 1

[Ilya]

Use a cell array. Pre-allocate the array by

ensemble = cell(rows,1);

And then assign using curly brackets:

ensemble{k} = tree;

[Rashid]

Thanks, this works very well!

Just a question - is it absolutely necessary to pre-allocate the array? My array will have dynamic nature, so I would prefer dynamic allocation of memory as well.

[Walter Roberson]

It is not absolutely necessary to pre-allocate: it is a matter of efficiency.