Table 1. The 22 features used to compare the sparse-grid density representation with the set of ligands in multiple conformations.

Feature type	No. of such features	Reference (where appropriate)
Third-order moment invariants	11	Lo & Don (1989 ▶); Hattne & Lamzin (2008 ▶)
Chirality index	1	Hattne & Lamzin (2011 ▶)
Features based on interatomic distances	2	Crippen & Havel (1988 ▶)
Features based on interatomic connectivity	4	Burden (1989 ▶, 1997 ▶)
Central moments of the Euclidean distances of the atomic coordinates	3	Tabachnick & Fidell (1996 ▶)
No. of atoms	1