8FUNCTIONS: heavyatom - CYANA function

Synopsis: heavyatom(<integer>) = <integer>

This function returns the index of the heavy atom associated with
the hydrogen or pseudoatom with index <integer>, or 0, if it is not
a hydrogen or pseudoatom.

Optionally, the <integer> atom index can be replaced by a string
consisting of the atom name and the residue number, separated by a
blank or a period, '.'.
