Frequently-asked questions (FAQ)

Running MatConvNet

Do I need a specific version of the CUDA devkit?

Officially, MathWorks supports a specific version of the CUDA devkit with each MATLAB version (see here). However, in practice we normally use the most recent version of CUDA (and cuDNN) available from NVIDIA without problems (see here).

Can I use MatConvNet with CuDNN?

Yes, and this is the recommended way of running MatConvNet on NVIDIA GPUs. However, you need to install cuDNN and link it to MatConvNet. See the installation instructions to know how.

How do I fix the error Attempt to execute SCRIPT vl_nnconv as a function?

Before the toolbox can be used, the MEX files must be compiled. Make sure to follow the installation instructions. If you have done so and the MEX files are still not recognized, check that the directory matlab/toolbox/mex contains the missing files. If the files are there, there may be a problem with the way MEX files have been compiled.

Why files such as vl_nnconv.m do not contain any code?

Functions such as vl_nnconv, vl_nnpool, vl_nnbnorm and many others are implemented MEX files. In this case, M files such as vl_nnconv.m contain only the function documentation. The code of the function is actually found in matlab/src/vl_nnconv.cu (a CUDA/C++ source file) or similar.

Why do I get compilation error error: unrecognized command line option "-std=c++11" on a Linux machine?

This is caused by an incompatible version of GCC compiler (<4.6) with your MATLAB. You can either install a newer version of GCC (if available), or you can force MATLAB not to use the offending compiler option and replace it with the previous name of the C++11 standard argument: * In MATLAB run: mex -setup c++. * Run edit(fullfile(prefdir, 'mex_C++_glnxa64.xml')) to edit your MATLAB compiler options. * Replace all occurrences of -std=c++11 with -std=c++0x and save the file.