torfinnberset / mex-it

Automatically mex C/C++ functions for Matlab or Octave (with C++11 compiler)

mex-it

C++ 11 code to automatically create Matlab mex function based on generic C++ functions.

###Only a single header file "mex-it.h" is required

The methodology is based on that used in the dlib library

• supply the mex_function and let the compiler do the rest.

However, the code was completely reworked to use as many classes from std C++11 as possible and to make use of variadic templates to greatly reduce the amount of code needed.

• Currently code to callback matlab is not part of this library.

This supports basic C++ data types. Has limited support for Eigen Matrices (Matrix type of double + ColMajor), plus Eigen Vectors (see examples)

####How does the compiler know the inputs and outputs?

• Non-const references mean outputs
• Everything else are inputs

Building

• Use either Cmake or setup your own mex script
• Works on Mac OS X, Linux & Windows (mingw32/g++ or Visual Studio 2013)

Build status

• Linux : Travis
• Windows/mingw32/g++/Octave 4.0 : AppVeyor

Example

Create a c++ implementation file like this

void mex_function(const double &x, const double &y, const double &z, double& result) {
	result = (x + y)*z;
}
#include "mex-it.h"

Matlab driver for this

x = 3;
y = 4;
z = 5;
result = simple_example(x,y,z);

Then build with CMake or using mex within Matlab

For single file example, you can do this in matlab (for recent GCC/Clang)

mex CXXFLAGS="\$CXXFLAGS -std=c++11" simple_example.cpp

Requirements

Eigen needed for Eigen examples

• Assumes Eigen is in either /usr/local/include/eigen3 or /usr/include/eigen3 or eigen3, please edit FindEigen.cmake for other paths

Other examples

C++ files starting with test_ are examples that can't generate mex files but do test the interfaces in pure C++ using mex header files

• test_eig_add.cpp -> Test of adding 2 Eigen Matrices of type 'double'
• test_eig_mult.cpp -> Test of multipling 2 Eigen Matrices of type 'double'
• test_vector_add.cpp -> Test of adding std::vector
• test_mex.cpp -> Uses include of 'mex_function.h' to test the function in 'mex_function.cpp'

Mex example

• eigen_add.cpp -> For creating mex function adds 2 eigen matrices
• simple_example.cpp -> A very basic example that returns (x+y)*z for inputs x,y, and z
• vector_example.cpp -> An example that returns (x+y)*z for inputs x,y, and z
• eigen_vector_example.cpp -> An example of a vector add for Eigen (double) vectors
• eigen_example.cpp -> Same example as in test_eig_add.cpp but here can generate a mex function

Matlab/Octave Scripts to test

• test_eigen_vector_example.m -> Test of adding 2 Eigen Vectors of type 'double' - also checks if wrong type is used
• test_eigen_matrix_example.m -> Test of adding 2 Eigen Matrices of type 'double' - also checks if wrong type is used
• test_vector_example.m -> Test of adding 2 std::vector - also checks if wrong type is used
• test_types.m -> Make sure input types match expected types