Returns sets of equivalent atoms with symmetry operations

Parameters:tolerance (float) – Tolerance to generate the full set of symmetry operations.
Returns:The returned dictionary has two possible keys:

eq_sets: A dictionary of indices mapping to sets of indices, each key maps to indices of all equivalent atoms. The keys are guaranteed to be not equivalent.

sym_ops: Twofold nested dictionary. operations[i][j] gives the symmetry operation that maps atom i unto j.

Return type:dict