Compiling the Borg Matlab Wrapper (Windows)

The Borg MOEA is written in C, but thanks to Dave, a Matlab wrapper is now available. This post will describe how to compile and use it on Windows. A separate post describes the process for OSX/Linux.

Step 0: Get Files

If you have access to the Bitbucket repository, you can grab the files there. If not, you’ll need to email someone to get them (I believe public releases are planned for the near future). The files you need are as follows: Borg.dll, Borg.lib, borg.m, DTLZ2.m, nativeborg.cpp, and borg.h. (Note: the last file is in the main directory, not the Matlab subdirectory). Students in CEE 6200 will have received these files in a zip folder; be sure to get the Windows-specific version.

Step 1: Check Compiler

Matlab needs to compile Borg into a mex file to call its functions directly. To do this, it needs access to a compiler. Unfortunately, it only looks for a few specific compiler types depending on your OS. (For example, if you’re using gcc in Cygwin, Matlab knows nothing about that). A list of compiler choices for Windows/Mac/Linux is given here:

You can check if you already have any of these installed by running mex -setup at the Matlab command line. (Note: NOT in your system terminal—which will either (1) do nothing, or (2) try to “make LaTeX”, neither of which you want right now). The mex -setup command will search for compilers. If it doesn’t find any, it will let you know.

Note: these instructions assume that you are using a reasonably recent version of Matlab. We’ve tested on 2013a specifically (64-bit). If you are using an older version of Matlab, the list of accepted compilers is completely different and may cause serious headaches if your Matlab is a 32-bit version. CEE 6200 students with older Matlab versions may want to try the computer lab in Carpenter instead; thanks to Jared Smith for testing these steps on the Carpenter computers.

(If it does find a compiler, congrats, you can skip ahead to Step 3!)

Step 2: Install Compiler

Assuming Matlab couldn’t find a compiler in the previous step, you’ll want to go install one. On Windows 7/8, Matlab encourages you to grab the Windows SDK.

Step 2b: Installation Troubleshooting

Windows: If you’re installing the Windows SDK for the first time, you may run into some problems. Specifically, if you already have Visual C++ 2010 installed, scroll to the bottom of these instructions from MathWorks and read the troubleshooting section. (Note: it is very likely that you have a version of Visual C++ installed, for one reason or another). The troubleshooting steps are: (1) uninstall the existing Visual C++ 2010, (2) Reinstall the Windows SDK, but de-select the Visual C++ 2010 options, and (3) Install a patch from Microsoft. Joe and I have successfully tested these steps on Windows 7 and 8 respectively , so with any luck this will be your only troubleshooting step.

Step 3: Compile Borg

In the Matlab command window, navigate to the directory where you stored all of the Borg files from Step 0. Run the command mex nativeborg.cpp Borg.lib. If it works, you’ll see a new file called nativeborg.mex* in your directory. (The * is “w64” for 64-bit Windows). If it doesn’t work, double-check that you have all of the files copied into the same directory, and that Matlab’s working directory is set properly.

Again: these commands are being run in Matlab’s command window, not the system terminal. Right now, the pre-compiled libraries (Borg.lib and Borg.dll) will only work for Windows. We are working on a set of steps for OSX/Linux users.

Step 4: Run a test problem

The file DTLZ2.m shows an example of how an objective function should be formatted for use with the Borg Matlab wrapper. It accepts a vector of decision variables as input, and outputs a vector of objectives (and optionally, constraints). From the command line, you can optimize this function as follows:

[vars, objs] = borg(11, 2, 0, @DTLZ2, 100000, zeros(1,11), ones(1,11), 0.01*ones(1,2));

The function returns the decision variables and objectives associated with non-dominated points (the Pareto-approximate set). The first three inputs to the function are: the number of decision variables, number of objectives, and number of constraints. After that comes the handle for your objective function, the number of function evaluations to run in the optimization, the lower and upper bounds of the decision variables, and finally, the epsilon precision values for the objectives.

To see the set of nondominated solutions, try scatter plotting the columns of the objs matrix:

scatter(objs(:,1), objs(:,2));

And you should see a semicircular-looking Pareto front. Now all you need to do is swap out DTLZ2 with an objective function or model of your choice, and you’ll be ready to go!

5 thoughts on “Compiling the Borg Matlab Wrapper (Windows)

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  5. Pingback: Update on setting up the Borg Matlab Wrapper on Windows and tips for its use – Water Programming: A Collaborative Research Blog

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