The MATLAB-interface is based on the integration of the C-routines by means of the MEX-functionality of MATLAB. A specificly implemented function acts as interface between the C-routines and MATLAB. By means of the MEX-function the functionality of the C-routines can directly be used inside of MATLAB similar as the inherent routines of MATLAB. This facilitates the combination of the C-routines with all the capabilities of MATLAB, including the numerical methods and visualization capabilities. In addition to the inherent visualization functions of MATLAB additional functions are available, which facilitate the generation of 3- and 4-component composition space diagrams (Gibbs triangles).