MATLAB: How to stack .mat files

mat filesxyz

Suppose in one of my data set, i have 20 .mat files.

Now, i want to stack all 20 .mat files together.

The issue is though they are in the same data set, size of each .mat file differs (not a huge variation though). As my final objective is to create a 3D model, how can i stack those .mat files together in order to open in another visualization software? Kindly (atleast) send me a link/documentation which help me to resolve this issue.

Best Answer

You cannot stack .m files. You might be able to stack variables that are stored in the files.

However, if the variables are not all the same size, you need to define how they are to align. Should they be rescaled (as if they are images of different resolution), or should the center all be in the same place and the smaller ones should be padded on all sides, or should the top left edge be aligned and the bottom right be padded on the smaller, or are these images containing features that have to be "registered" (lined up), or ... ?

Related Solutions

MATLAB: Load several .mat files with n x n matrices and compute average

http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

http://matlab.wikia.com/wiki/FAQ#How_can_I_create_variables_A1.2C_A2.2C....2CA10_in_a_loop.3F

If the variables are all the same 2D size, then the most efficient thing to do is load them one at a time and store the value into a slice of an array. Then once you have all of the data loaded, you can mean() across the third dimension.

dinfo = dir('matrix*.mat');
nfile = length(dinfo);
if nfile == 0
   avg = [];
   warning('There were no input files');
else
  filestruct = load(dinfo(1).name);
  fn = fieldnames(filestruct);
  thisvar = filestruct.(fn{1});
  orig_size = size(thisvar);
  input_data = [thisvar(:), zeros(numel(thisvar), nfile-1, class(thisvar))];
  for K = 2 : nfile
    filestruct = load(dinfo(K).name);
    fn = fieldnames(filestruct);
    thisvar = filestruct.(fn{1});
    if ~isequal(size(thisvar), orig_size)
       error('file "%s" has a different size of matrix than the first file "%s"', dinfo(K).name, dinfo(1).name);
    end
    input_data(:,K) = thisvar(:);
  end
  input_data = reshape(input_data, [orig_size, nfile]);
  avg = mean(input_data, ndim(input_data));
end

(with data of an unknown number of dimensions, it turned out to be easiest to store the data as columns and reshape afterwards.)

MATLAB: Is the structure created from a GenBank-file within the Bioinformatics Toolbox 1.0 (R13SP1+) missing the “Sequence” information

The BASECOUNT line has been removed from GenBank-files in Release 137 format. The GENBANKREAD function, used to read in the GenBank-files, looks for the BASECOUNT line before it reads in the sequence information. If this line is not found, the function stops reading from the file.

An updated version of the GENBANKREAD function is available here:

http://www.mathworks.com/help/bioinfo/ref/genbankread.html

Use it to replace the $MATLAB/toolbox/bioinfo/bioinfo/genbankread.m file (where $MATLAB is the root directory of your MATLAB installation).

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Related Solutions

MATLAB: Load several .mat files with n x n matrices and compute average

MATLAB: Is the structure created from a GenBank-file within the Bioinformatics Toolbox 1.0 (R13SP1+) missing the “Sequence” information

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