Figure . A demonstration of how the SingleGraph module generates SMIRKS. The user provides a molecule object, in this case ethanol, and specifies which atoms should be tagged (pink). The number of "layers" determines how many non-indexed atoms should be included. With = 1, the atoms one bond away (yellow) are included. To include all atoms in a molecule, adding the blue ones in this example, can be set to } . ′ The SMIRKS, shown in the table at the right, can include all decorators (complex) or just the atomic numbers (compressed). layers=0