def precompute_optimzation_Y(laplacian_matrix, n_samples, relaxation_kwds):
    """compute Lk, neighbors and subset to index map for projected == False"""
    relaxation_kwds.setdefault('presave',False)
    relaxation_kwds.setdefault('presave_name','pre_comp_current.npy')
    relaxation_kwds.setdefault('verbose',False)
    if relaxation_kwds['verbose']:
        print ('Making Lk and nbhds')
    Lk_tensor, nbk, si_map = \
        compute_Lk(laplacian_matrix, n_samples, relaxation_kwds['subset'])
    if relaxation_kwds['presave']:
        raise NotImplementedError('Not yet implemented presave')
    return { 'Lk': Lk_tensor, 'nbk': nbk, 'si_map': si_map }
compute Lk, neighbors and subset to index map for projected == False