The OccQP software was first described in the article "Optimization of site-occupancies in minerals using quadratic programming" by S.E. Wright, J.A. Foley, and J.M. Hughes, American Mineralogist 85 (2000), 524-531. Additional details on using OccQP are available in this PDF manual.
OccQP was designed for use within the MATLAB mathematical computing environment. The most recent major OccQP update with a graphical user interface occurred in 2006 and the resulting MATLAB p-code file was verified to work with MATLAB releases as late as 2010. That version can be downloaded by using your browser's "Save as" or "Save target as" or "Save link as" feature to select Version 0.51. Later releases of MATLAB may work better with Version 0.52, which includes a few adjustments that were needed following MATLAB updates in 2011. To use either of these P-file versions of the software, rename the downloaded file as 'occqp.p' (without the quotation marks) and place it in a folder on your MATLAB path. Within MATLAB run the program by typing occqp (in lower case) at the >> command prompt.
Editable M-file source code for a self-contained version of OccQP with a command-line interface is available. This file does not include code for the graphical user interface because that aspect of the program no longer works with current versions of MATLAB. Nevertheless, this source code can be of value to those who work with particularly complex mineral structures, use alternative platforms like Octave instead of MATLAB, need to modify/explore the code for some reason, or wish to port the methodology to another programming language. The code was extracted with minor modifications from Version 0.52 in 2019 and appears to work under MATLAB R2017A, but it has not been extensively tested against any version of MATLAB. Type 'help occqp_cmd' at the MATLAB prompt for instructions on running this version of OccQP.
OccQP is no longer supported by the authors.