There are 4 different subgroups and 3 main groups involved in the calculation. These are shown together with their ID (group number) and (in case of subgrous) the R and Q values in the following vectors. In order to identify the main group that a subgroup belongs to, the index vector s2m is defined. s2m_{i} yields the main group address in the main group vectors, that subgroup i belongs to. The matrix contains the frequency of subgroup i in component j. The matrices , and contain the coefficients for the temperature dependent interaction parameters.