Mat-File Version with 2019b Anomaly?

Hello, I am trying to save an image array (cell array of images) to a mat file and Im expecting the filesize to be smaller than just saving as tiffs, but had an error message

Warning: Variable 'imgArray' was not saved. For variables larger than 2GB use MAT-file version 7.3 or later.

As I had matlab 2019b, I thought I would have the latest and greatest MAT-file version,

If I type the following ont he command line,

>> x = evalc(['type(''', savepath, ''')'])

It returns:

MATLAB 5.0 MAT-file, Platform: PCWIN64, Created on: Mon Feb 3 09:27:40 2020

So Im wondering

a: Why dont I have the latest version?

b: How do I get the latest version

Answer 1

[Walter Roberson]

Use the -v7.3 option when you save.

Alternatively, if you go into Preferences then you can set v7.3 save as the default. That is, however, not generally desirable unless you are saving large objects or you specifically need to save with hdf5 compatibility.

[Jason]

Thanks Walter, could you expand on why its not desirable for non large objects?

[Walter Roberson]

The hdf5 format used by -v7.3 is a fair bit less efficient, except perhaps for the case of a single numeric array (and I would have to check the details for that case.) in particular it is much worse for structure arrays or cell arrays or tables or objects...

[Jason]

Thankyou