8FUNCTIONS: stereopartner - CYANA function

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

Number of the diastereotopic partner of atom n. If atom n has
no stereopartner, the function returns 0. If the atom (and its
stereopartner) are stereospecifically assigned (see command atom
stereo), the function returns the number of the diastereotopic partner
with a negative sign.
