Question

I have a large .mat file. I call it D.mat. It has a cell inside it (D.X is a cell array). I need to add more data to the end of its only column and I cannot load it into the memory.

I read about this function: memmapfile and Mapping Multiple Data Types and Arrays section, but it seems that I should know the structure of the data and in fact the D.X elements has no definite structure.

I thought maybe there is a function like fgetl for these kind of situations (I mean read the file to its last index (or row) and then write to it).

Is it possible?

Any help is appreciated.

Answer 1

If you have access to version R2011b or later, you can use the matfile command to load and save parts of variables in a .mat file, without loading the data into memory. See doc matfile for more information and some examples.

fgetl is not what you need: it’s for reading lines from a text, not .mat file. memmapfile also requires that the data file be laid out in a regular structure, which is not the case for a .mat file.

Before R2011b there is no way I know of doing what you need.