@staticmethod
def convert_to_P1(reflections, experiments):
    """Convert the input crystals to P 1 and reindex the reflections"""
    from cctbx.sgtbx import space_group
    for iexp, exp in enumerate(experiments):
        sel = reflections['id'] == iexp
        xl = exp.crystal
        sg = xl.get_space_group()
        op = sg.info().change_of_basis_op_to_primitive_setting()
        exp.crystal = xl.change_basis(op)
        exp.crystal.set_space_group(space_group('P 1'))
        hkl_reindexed = op.apply(reflections['miller_index'].select(sel))
        reflections['miller_index'].set_selected(sel, hkl_reindexed)
    return reflections, experiments
