8FUNCTIONS: coord - CYANA function

Synopsis: coord(<integer>,<integer>) = <real>

Function that returns a Cartesian coordinate of an atom. The first
<integer> argument denotes the atom index, the second <integer>
argument the dimension (1, 2 or 3).

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, '.'.
