Even in well-behaved cases, however, the resulting heatmap is only interpretable to a degree. In the case of saccharine for example, it is less clear why the oxygen atoms are particularly anti-correlated with sweetness. Similarly for the alkane 6, it is rather the absence of any features that leads to it being classified as undefined. Nonetheless, these interpretability tools help rationalize FART's predictions and may aid in producing analogs by highlighting parts of the structure that can be altered without changing the label, see SI for an example use case.