These methods will return the value for the corresponding
descriptors. While they can always be evaluated using
eval.desc, they are common enough that separate
functions are provided.
Single numeric value representing TPSA, ALogP or XLogP
Details
It's important to note that ALogP and XLogP assumes that the molecule
has explicit hydrogens. If the molecule is read from an SD file,
explicit H's are usually present. On the other hand, if the molecule
is obtained from a SMILES, explicit hydrogens must be added.