Fig. 3

Representation of Θ coefficients for stage 4S and stage 4 tumors. The stage 4S (a) and stage 4 (b) tumors are reported in the columns, whereas the atoms are in the rows. Each sample is approximated by a linear combination of atoms weighted by the Θ coefficients. The atoms in the Θ matrix are sorted according to their use in the sample representation, i.e., the most used atoms are in the top rows. The coefficients range from 0 to 1, as indicated by the underlying color bar, and darker hues correspond to higher coefficient values