Fig. 6: Binary sparse coding QUBO model coefficient matrices.

Colormaps of the full QUBO symmetric matrix for a (randomly chosen and representative) sparse coding QUBO with 64 variables (left) and 128 variables (right). Each heatmap corresponds to the coefficient for each of the linear terms (on the diagonal) and for each of the quadratic terms (on the off-diagonals). The axis labels correspond to the matrix row and column indices.