How can I share memory between processes in MATLAB?

Question

Is there any way to share memory between MATLAB processes on the same computer?

I am running several MATLAB processes on a multi-core computer (running Windows, if i

Answer 1

Probably not, at least not in the way where you treat the data like a regular MATLAB variable.

If on a Windows machine, you could create a COM/ActiveX wrapper to access your shared data. MATLAB allows the use of COM objects through the actxserver function. But it's questionable whether you could actually access the data "directly" through different processes. There's some kind of marshaling layer between MATLAB and COM and data gets converted, at least according to the Mathworks docs on exchanging data between MATLAB and COM. If I absolutely had to share structured data between processes, with fast access, on a Windows machine, I'd probably write something in C++ to use shared memory via Boost::interprocess and wrap access to it in an in-process COM server (DLL). I've done this before, once. As much as Boost::interprocess makes it a lot easier, it's a pain.

The Java approach (since MATLAB runs on top of Java) would be much more promising, but as far as I know, there aren't any decent Java libraries to provide access to shared memory. The closest thing is probably to use a memory-mapped file via java.nio.MappedByteBuffer, but that's really low-level. Still, if your data is in a relatively "square" form (e.g. a big 2-D or 3-D or 4-D matrix of homogeneously-sized data) this might work OK.

You could try to use HDF5 files, MATLAB has built-in HDF5 support and it's "relatively" fast. But from my experience, HDF5 doesn't seem to play very well with concurrency. (at least not when one process is writing and the others are readers. If there are multiple readers and no writers, it works just fine.)