In theory, 32-bit applications can address up to 4GB of virtual memory.
However, a number of things affect the actual memory accessibility:
1. The Operating System reserves memory for itself, reducing the amount of memory its applications can use.
2. Other applications running at the same time can eat up memory as well.
3. MATLAB reserves memory for itself. Even when there is no code running and there are no variables in the workspace, MATLAB is still using memory.
4. The memory available to MATLAB may be fragmented when starting additional tools or toolboxes, or loading MATLAB functions into memory. This limits the size of the largest contiguous block of memory. Since MATLAB matrices need to be stored in contiguous blocks, Out of Memory errors can occur while trying to create a matrix larger than the size of the largest contiguous block, even if that memory exists in several fragmented blocks.
There are tools for memory management for Macs:
The TOP command allows you to view the RPRVT (amount of memory in use) and VSIZE(amount of virtual memory paged so far) for the applications with top CPU usage:
top
To access more memory you can run MATLAB from xterm with –nojvm option:
matlab –nojvm
which does not load Java Virtual Machine and thus saves memory MATLAB uses for itself otherwise.
For more on Memory Management, please refer to the following Tech Notes:
