Changing the format of mat file

How to change the format of the mat file ? My data is in form of : epoch *data point *channel. I want to change the format as : channel* data point* epoch

Answer 1

[Mohammad Sami]

If you have a 3D matrix, you can use the function permute to move the dimensions.

edc = rand([3 4 5]);
cde = permute(edc,[3 2 1]);
% this will make the 3rd dimension the first dimension and first dimension the third.

[Walter Roberson]

Note that this works on a variable. You had asked to convert a file; the framework I gave goes through the file and converts all of the variables in it and creates a new file with the result.

Answer 2

[Walter Roberson]

outdir = 'swapped';            %can be fully qualified

filename = 'YourFile.mat';     %can be fully qualified

if ~exist(outdir, 'dir'); mkdir(outdir); end

ds = load(filename);
fn = fieldnames(ds);
nf = length(fn);
all_3d = true;
for K = 1 : nf
    thisfield = fn{k};
    thisdata = ds.(thisfield);
    if ndims(thisdata) ~= 3
        fprintf('variable "%s" is not 3D, quitting!\n', thisfield);
        all_3d = false;
        break;
    end
end
if all_3d
    nf = struct();
    for K = 1 : nf
      thisfield = fn{k};
      thisdata = ds.(thisfield);
      newdata = permute(thisdata, [3 2 1]);
      nf.(thisfield) = newdata;
    end
    [filedir, basename, ext] = fileparts(filename);
    newname = fullfile(outdir, [basename ext]);
    save(newname, '-struct'. 'nf')    
end