def coord_to_index_(coord, map_obj):
    """
    Converts atomic residue coordinates into map indices
    :param coord: coordinate in angstrom
    :param map_obj: map object
    :return: float indices
    """
    return coord[2] / map_obj.voxel_size[2] - map_obj.origin[2] / map_obj.voxel_size[2] - map_obj.n_start[2], \
           coord[1] / map_obj.voxel_size[1] - map_obj.origin[1] / map_obj.voxel_size[1] - map_obj.n_start[1], \
           coord[0] / map_obj.voxel_size[0] - map_obj.origin[0] / map_obj.voxel_size[0] - map_obj.n_start[0]