Mex Multithreading

Example of (Windows) multi-threading in a MEX file

Description

Nowadays, Matlab is multi-threaded but most MEX files are still single threaded. This is an simple example of c-code for MEX file multi-threading.

The mex function "y = square(x)" is written in c-code and starts 2 worker threads. The first worker thread will square all values on the even input indexes x[0] x[2] .. x[n], and the second worker thread all odd indexes x[1] x[3] .. x[n]. Also demonstrates thread safety by using Mutex to lock percentage variable.

example,
mex square.c -v;
y = square([1 2 3 4 5 6 7 8 9])

note:
The function uses <windows.h> (function sleep ) and <process.h> ( function _beginthreadex ) which are included with visual studio and some other compilers.

This example is tested with Windows Vista 64 and Visual Studio 2008 compiler, and with (default) LCC compiler and Vista 32.

• MATLAB release: MATLAB 7.6 (R2008a)
• Other requirements: Windows OS

[Nick Clark]

Nice submission. Cute example and easy to understand. Check out Intel TBB for more scalability, especialy now it is available free of charge. Thanks again :D

[A B]

Excellent introduction to multithreading inside a mex function.

[Jveer]

can this capability be compiled into a standalone application using the matlab compiler?

[Ad Client]

Very well commented . There is a typo in square.c line 144 col 41 - should be double "%" to actually print out.
Tested on WinXP64bit Pro - works.