Figure 5

Boxplot plot visualization of ratios to optimal angles’ per clustering method and depth on MaxCut (a) and dense QUBOs (b), when using instance features. For Erdős-Rényi graphs, K-means yielded ratios 0.996214, 0.996368 with 3, 4 clusters and 0.998429 with 10. On dense QUBOs, we obtained respective median ratios of 0.963129, 0.971778 and 0.982964. With reference to the optimal angles’ expectation value, this corresponds on average to a less than 1–2% reduction in performances when using 10 clusters