Similarly, we grouped molecules with three or fewer rotatable bonds together. In addition, we combined molecules with five or more rotatable bonds together in Case (1) due to the small sample size in molecules with six rotatable bonds. Wilcoxon signed-rank tests for the RMSD and TFD distributions showed consistent results (see Additional File 4): the distribution of conformers generated by uniform random search is significantly different from that generated by BOA (p-value 0.01). The conformers generated by BOA with both acquisition functions, EI and LCB, are not statistically different from each other.