  The problem addressed here can be concisely formulated as follows: given a
stable surface orientation with a known reconstruction and given a direction in
the plane of this surface, find the atomic structure of the steps oriented
along that direction. We report a robust and generally applicable
variable-number genetic algorithm for step structure determination and
exemplify it by determining the structure of monatomic steps on
Si(114)-$2\times 1$. We show how the location of the step edge with respect to
the terrace reconstructions, the step width (number of atoms), and the
positions of the atoms in the step region can all be simultaneously determined.
