The most efficient method to start a matlab code within a C-Routine

As a part of my masters thesis I am programming an external C-Subroutine for a MBS-Software in order to work as a force element like e.g.:

force=subfunction(displacement)

There is a Matlab code doing this and very time-consuming to implement it in C.

So the following options I considered to overcome this the most efficient way:

1. Using Matlab-Compiler to create a .exe and start it from C

Very nice and easy solution. However the problem is that the mbs-solver calls the function >10000 times and the compiled Matlab executable has to load the MCR (Matlab Compiler Runtime) every single time! The processing time is very short (~0.001 seconds) but the loading of MCR takes about 5 seconds (!) for each iteration step. This makes this option unfortunately useless for me.

http://www.mathworks.de/support/solutions/en/data/1-1ARNS/

"Every time you start a compiled executable, you essentially start another instance of MATLAB."

2. Using Matlab-Compiler to create a shared library etc.

I haven't tried this. As far as I researched I understood that also for these options the MCR has to be started every single step like the option 1.

3. Using the Matlab-Coder to generate a C-Code

It's not an easy option as far as I tried sometimes. The generated code should be optimized. Would it really be more efficient?

4. Starting Matlab-Executable only the first time without closing it and communicating the C-Code over any files

Just a conception: I would like to start Matlab-Exe. in the first iteration step and let write a file which contents "displacement". Then I would scan every milisecond the file from Matlab if any new value came. I would process it and write in another file and the C-Routine that scans the result file every milisecond would find the new value and keep working.

I can imagine that this works faster but surely it's bit tricky to implement until it works bugfree.

I am thankful for any reports about your experiences or ideas.

Answer 1

[Ryan Livingston]

Hopefully someone corrects me if I am wrong but option 2 should give you what you want if you are using MATLAB Compiler already. The general workflow for generating and using a shared library is described here:

http://www.mathworks.com/support/solutions/en/data/1-F9VB0V/index.html

Notice that the MCR need only be initialized once. Then your entry point function(s) can be called at will and should utilize that same MCR.

Option 3 will be able to give you fully standalone C code which runs free from the MCR. If you need such a thing then that may be desirable.