pack command with saving v7.3

Hi,

I have an issue with the pack command. I am reading a very large (.dat) file (3GB in size), and cataloging entries from it. I am able to read this file into Matlab, access the stored variable, and query all entries.

In each loop iteration, I am reading and parsing rows of the variable. Every so often, I save the current index (and some minor information, not totalling 3KB), clear the current variables, and continue. The current variables that are cleared are a subset of the large .dat file from which I was reading.

I found out there is an issue with Matlab freeing previously allocated memory ( link ), so I am attempting to use the pack command. However, I get this error when saving the (.dat) file:

>> pack
Warning: Variable 'gt' cannot be saved to a MAT-file whose version is older
than 7.3.
To save this variable, use the -v7.3 switch.
Skipping...

I need this variable, but I could not figure out how to call pack with the -v7.3 flag, as when calling save ( link2 ). I tried this:

>> pack('-v7.3');
Error using save
Unknown command option.

and this:

>> pack('testtmp.mat','-v7.3');
Error using pack
Too many input arguments.

Any ideas?

Thanks in advance.

[Philip Borghesani]

When using 64 bit MATLAB I expect there is little benefit to calling pack. Much of the information in the link you quoted is misleading or does not apply to 64 bit MATLAB. If you have a memory related problem I suggest you post a new question with information about your real problem and look for a solution.

Answer 1

[Tushar Sinha]

Hi Abhejit,

This is a known issue in MATLAB. The 'pack' command cannot save variables that are larger than 2GB in size, and as a result, those variables are lost.

The workaround for this issue is to save the workspace using the 'save' command with the '-v7.3' option, then execute 'pack', then load the saved data. For example:

>> save('data.dat', '-v7.3')
>> pack
>> load('data.dat')

I hope this resolves the issue.

Thanks,

Tushar