All combination for a cell structure?

Hi all,

I'd like to get all combinations for all elements in a cell structure. For example,

var = rand(20, 3);
no = 5;
numcell = mat2cell(var, size(var, 1)/no*ones(1, no), ones(1, 3));

result in a 5 by 3 cell 'numcell' which contains 4 by 1 double for each cell.

I'd like to find all combinations among 5 by 3 'numcell', performing the calculation numcell{:}*numcell{:}' for each cell element of numcell. So that I'll get all permutation and combination of numcell{i}'*numcell{j}.

Thanks!

[Stephen23]

Continuation of this question:

http://www.mathworks.com/matlabcentral/answers/304204-all-combinations-of-matrix-elements

Answer 1

[Andrei Bobrov]

I correctly understand:

out = cellfun(@(x)a(:).'*a(:),numcell);

[Xiaohan Du]

Hi Andrei,

Sorry for my explanation, the 'out' is not what I wanted. I meant all permutation and combinations of cells in numcell.

I've corrected my question, please see it.

[Andrei Bobrov]

Maybe as?

a = cat(2,numcell{:});
M = a.'*a;

[Xiaohan Du]

I think this is it! Thanks a lot!

[Stephen23]

@Xiaohan Du: so what is the point in converting the data to a cell array, when the first step when performing this calculation is to get all the numeric arrays out of the cell array and concatenate them together?

Why bother with the cell array at all, when you don't use it for anything?

[Andrei Bobrov]

I am agree with Stephen, just:

a = reshape(var,4,:);
M = a.'*a;