Be careful with this one, the premise is sound (coming from a DL background), but I skimmed the paper and didn't see them comparing it to existing simple compounds and don't show if their compounds are actually any better.
Expensive or not, they didn't do it, so we don't know if those compounds actually work.
Am I missing something or did they also not use a held-out validation dataset to assess performance? It seems to me they ran their autoencoder, got some suggested compounds, listed anecdotal evidence about those compounds, and called it a day.
