8FUNCTIONS: ida - CYANA function

Synopsis: ida(<integer>,<integer>) = <integer>

This function returns the index of the m-th defining atom of the
dihedral angle with index n, where n = 1,...,nd denotes the first
argument and m = 1,...,4 the second argument.

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