pack (MATLAB Functions)

Consolidate workspace memory

Syntax

```
pack
pack filename
pack('filename')
```

Description

pack frees up needed space by reorganizing information so it only uses the minimum memory required. You must run pack from a directory for which you have write permission. Running pack clears all variables not in the base workspace, so persistent variables, for example, will be cleared.

pack filename accepts an optional filename for the temporary file used to hold the variables. Otherwise, it uses the file named pack.tmp. You must run pack from a directory for which you have write permission.

pack('filename') is the function form of pack.

Remarks

The pack function does not affect the amount of memory allocated to the MATLAB process. You must quit MATLAB to free up this memory.

Since MATLAB uses a heap method of memory management, extended MATLAB sessions may cause memory to become fragmented. When memory is fragmented, there may be plenty of free space, but not enough contiguous memory to store a new large variable.

If you get the Out of memory message from MATLAB, the pack function may find you some free memory without forcing you to delete variables.

The pack function frees space by:

Saving all variables in the base workspace to disk in a temporary file called pack.tmp
Clearing all variables and functions from memory
Reloading the base workspace variables back from pack.tmp
Deleting the temporary file pack.tmp

If you use pack and there is still not enough free memory to proceed, you must clear some variables. If you run out of memory often, you can allocate larger matrices earlier in the MATLAB session and use these system-specific tips:

UNIX: Ask your system manager to increase your swap space.
Windows: Increase virtual memory using the Windows Control Panel.

To maintain persistent variables when you run pack, use mlock in the function.

Examples

Change the current directory to one that is writable, run pack, and return to the previous directory.

```
cwd = pwd;
cd(tempdir);
pack
cd(cwd)
```

See Also

clear

otherwise pagedlg