Pack/Unpack Logicals
Compress large logical variables to one bit per element, instead of the usual 8.
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MATLAB (6.5 at least) stores logical variables in memory as 8 bits per element, even though only one bit is required. This means a 512x512x100 logical mask takes up 25 MB of memory. By compressing this mask the same amount of data takes only 3MB.
A limitation is that compressed logicals are stored in a struct array, and cannot be operated on in a meaningful way without unpacking them. I use this compression to store many large masks in memory, and then I unpack them when I am ready to use them.
Cite As
James Alaly (2026). Pack/Unpack Logicals (https://www.mathworks.com/matlabcentral/fileexchange/6586-pack-unpack-logicals), MATLAB Central File Exchange. Retrieved .
General Information
- Version 1.0.0.0 (2.82 KB)
MATLAB Release Compatibility
- Compatible with any release
Platform Compatibility
- Windows
- macOS
- Linux
| Version | Published | Release Notes | Action |
|---|---|---|---|
| 1.0.0.0 | Updated to store size of original logical vector/array in the packed data structure. Idea by Iram Weinstein. Also added a function isPackedLogical to test if a variable needs to be unpacked. |
