How do I run PCA on multiple cell arrays

Hi,

I have a cell array (see attachment) where each cell contains an array with 21 columns (variables). Each cell represents a different participants and is of different length. I would like to run the PCA on each cell in the cell array and collect the outputs (coeff,score,latent,tsquared,explained,mu) for all participants.

The fucntion I want to use is the following with X being my cell array pre_data_1.

[coeff,score,latent,tsquared,explained,mu] = pca(X)

I am specifically interested in getting an "explained" that contains all the explained variables from each participant. In this variable each column should correspond to an explained variable from a cell/ participant.

I wonder if someone could help me with that?

Answer 1

[Image Analyst]

Did you try something like

numCells = numel(X);
for k = 1 : numCells
    % Extract contents of cell into array.
    thisX = X{k}; 
    % Do PCA and store results in more cell arrays.
    [coeff{k},score{k},latent{k},tsquared{k},explained{k},mu{k}] = pca(thisX); 
end

It's untested on your data. It's just off the top of my head.

[lil brain]

Hi, thank you. When I run this code it tells me thisX needs to be a numeric array.

thisX is a 2x1 cell array.

[Image Analyst]

So you have a 2-by-1 cell array inside each cell of a parent/containing cell array? What's in those cells? Basically you have to go inside your cells deep enough to get the actual numerical arrays. Attach your cell array in a .mat file with the paperclip icon if you don't know how to do that.

[lil brain]

Hi, sorry I had already attached it in retrospect. But I decided to just convert all the cells to doubles using cell2mat like so:

pre_data_mat = cellfun(@cell2mat,pre_data1,'UniformOutput',false);

[Image Analyst]

So did my answer work then?

[lil brain]

yes :)