def METHOD_NAME(space_group_info,
           step = 0.6,
           d_min = 4.0):
  r = (-1.05,-0.1,0.0,1.05,0.1)
  n_sym = space_group_info.type().group().n_smx()
  if(n_sym != 8):
     for x in r:
      for y in r:
       for z in r:
         symmetry = crystal.symmetry(unit_cell = space_group_info.any_compatible_unit_cell(volume= 2000),
                                     space_group_info = space_group_info)
         #symmetry = crystal.symmetry(unit_cell=(11., 12., 13., 75., 85., 95.),
         #                            space_group_symbol="P1")
         #symmetry = crystal.symmetry(unit_cell=(11., 12., 13., 90., 90., 90.),
         #                            space_group_symbol="p212121")
         structure = xray.structure(crystal_symmetry=symmetry)
         scatterer = xray.scatterer(
                          site = (x,y,z),
                          u = 0.1,
                          occupancy = 1.0,
                          scattering_type = "O")
         structure.add_scatterer(scatterer)
         fc = structure.structure_factors(d_min = d_min,
                                          anomalous_flag=False,
                                          algorithm="fft").f_calc()
         manager = max_like_non_uniform.ordered_solvent_distribution(
                                         structure = structure,
                                         fo = fc,
                                         grid_step = step)
         f_water_dist = manager.fcalc_from_distribution()
         ### check phase compatibility with the symmetry:
         centrics = f_water_dist.select_centric()
         if(centrics.indices().size() > 0):
            ideal = centrics.phase_transfer(centrics)
            assert flex.max(flex.abs(ideal.data() - centrics.data())) < 1.e-6
         ###
         #print "max = ", flex.max( flex.abs( f_water_dist.data() ) )
         #print "min = ", flex.min( flex.abs( f_water_dist.data() ) )
         #print "ave = ", flex.mean( flex.abs( f_water_dist.data() ) )
         assert flex.max( flex.abs( f_water_dist.data() ) ) < 1.0