Accessing elements of a large cell array inside a MAT file?

I have a huge (~25gb) cell saved in a 7.3 format MAT file, and I want to access just a few entries from it. I tried to write some code to pull out only the data I need, initially using the matfile command to access the data I need;

inputdata = matfile('fullsetrc150.mat');
data_acquired = inputdata.Segframe{1,401}{1,3};

However as I understand it, matfile cannot handle cell operations, so I am stuck with a massively time and memory consuming script like this instead;

inputdata = matfile('fullsetrc150.mat');
chunk = inputdata.Segframe;
data_acquired = chunk{1,401}{1,3}; 
clear chunk;

This can take literally hours to run and is incredibly inefficient; is there a more clever way to access just the data I need, or must I load the entire cell to pull values from it? Any advice is welcome!

Answer 1

[Guillaume]

Unfortunately, matfile is the only interface that matlab provides to read parts of a mat file. And as the documentation says, it cannot read just part of a cell array.

I would look on the file exchange to see if somebody has a partial loader for cell arrays. Otherwise, I'm afraid you would have to write your own parser, either as a matlab function or a mex file (for performance) based on mathworks' description of the mat file format.

Answer 2

[Stalin Samuel]

first load the .mat file.then you will have all the variables in your workspace.Now you can directly access the variables

[David Robert Grimes]

Afraid that's not possible - file is so large it crashes this workstation with an out of memory error.