Optimization of mixture components weights corresponding to integer somatic multiplicities may be accomplished in a manner similar to that described for the SNCA mixture model in eq. (6). A Dirichlet prior may be specified as a vector of pseudo-counts equivalent to prior observations of each multiplicity value. Weights are then calculated as the mode of the posterior Dirichlet calculated from the observed counts. These computations are used to calculate a mutation-score likely for each purity ploidy mode when ABSOLUTE is run with paired SCNA and somatic point mutation data.
