Is a basis vector, in units of ALAT and in
cartesian coordinates. The basis could alternatively be given in units
of the translation vectors **a**, **b**, and **c** (see token X=).
Some of the programs require the most compact basis position i.e.
positions closest to the origin. These new positions are calculated
by the programs and written back into the CTRL file.

Thu Oct 12 14:48:45 MESZ 2000