Figure 2. Application to gene expression microarray data from blood disorders.

Columns indicate components, rows classes of blood cells. Blue cells indicate significant enrichment of cell type-specific markers (as detected by gene set enrichment testing; ) in the component generated by rNMF with 90% sparsity (a) and conventional NMF (b). The components have been ordered by strength (defined as norm of ) with denoting the strongest component. As discussed in detail in Results, strong components generated by rNMF capture cell type-related gene expression features more clearly than conventional NMF.