The matrix of multinomial logit coefficients of the TPM are kept in the Matrix class. The primary function of this class is to calculate transition probabilities for a grid cell using the logit coefficients and the LCL corresponding to that grid cell. Once the transition probabilities have been calculated, a random integer is generated by the R250 class object (Section 4.1.6). This determines which value the new grid cell should be assigned. The method for calculating transition probabilities to determine transitions is discussed at length in Section 3.2.