How to compute the Area of Feasible Solutions

The area of feasible solutions (AFS) is a low dimensional representation of the set of all possible nonnegative factorizations of a given spectral data matrix. The AFS can be used to investigate the so-called rotational ambiguity of MCR methods in chemometrics, and the AFS is an excellent starting point for feeding in additional information on the chemical reaction system in order to reduce the ambiguity up to a unique factorization. The FAC-PACK program package is a freely available and easy-to-use Matlab toolbox (with a core written in C and FORTRAN) for the numerical AFS computation for twoand three-component systems. The numerical algorithm of FAC-PACK is based on the inflation of polygons and allows a stable and fast computation of the AFS. In this contribution we explain all functionalities of the FAC-PACK software and demonstrate its application to a consecutive reaction system with three components.