Beispiel #1
0
def test_coupling_terms():
    L = 4
    sites = []
    for i in range(L):
        s = site.Site(spin_half.leg)
        s.add_op("X_{i:d}".format(i=i), 2. * np.eye(2))
        s.add_op("Y_{i:d}".format(i=i), 3. * np.eye(2))
        sites.append(s)
    strength1 = np.arange(0., 5)[:, np.newaxis] + np.arange(
        0., 0.625, 0.125)[np.newaxis, :]
    c1 = CouplingTerms(L)
    for i, j in [(2, 3)]:
        c1.add_coupling_term(strength1[i, j], i, j, "X_{i:d}".format(i=i),
                             "Y_{j:d}".format(j=j))
    assert c1.max_range() == 3 - 2
    for i, j in [(0, 1), (0, 3), (0, 2)]:
        c1.add_coupling_term(strength1[i, j], i, j, "X_{i:d}".format(i=i),
                             "Y_{j:d}".format(j=j))
    c1_des = {0: {('X_0', 'Id'): {1: {'Y_1': 0.125},
                                  2: {'Y_2': 0.25},
                                  3: {'Y_3': 0.375}}},
              2: {('X_2', 'Id'): {3: {'Y_3': 2.375}}}} # yapf: disable
    assert c1.coupling_terms == c1_des
    c1._test_terms(sites)
    assert c1.max_range() == 3 - 0
    tl1 = c1.to_TermList()
    term_list_des = [[('X_0', 0), ('Y_1', 1)], [('X_0', 0), ('Y_2', 2)],
                     [('X_0', 0), ('Y_3', 3)], [('X_2', 2), ('Y_3', 3)]]
    assert tl1.terms == term_list_des
    assert np.all(tl1.strength == [0.125, 0.25, 0.375, 2.375])
    ot1, ct1_conv = tl1.to_OnsiteTerms_CouplingTerms(sites)
    assert ot1.onsite_terms == [{}] * L
    assert ct1_conv.coupling_terms == c1_des

    mc = MultiCouplingTerms(L)
    for i, j in [(2, 3)]:  # exact same terms as c1
        mc.add_coupling_term(strength1[i, j], i, j, "X_{i:d}".format(i=i),
                             "Y_{j:d}".format(j=j))
    assert mc.max_range() == 3 - 2
    for i, j in [(0, 1), (0, 3), (0, 2)]:  # exact same terms as c1
        mc.add_coupling_term(strength1[i, j], i, j, "X_{i:d}".format(i=i),
                             "Y_{j:d}".format(j=j))
    assert mc.coupling_terms == c1_des
    assert mc.max_range() == 3 - 0
    mc.add_multi_coupling_term(20., [0, 1, 3], ['X_0', 'Y_1', 'Y_3'],
                               ['Id', 'Id'])
    mc.add_multi_coupling_term(30., [0, 1, 3], ['X_0', 'Y_1', 'Y_3'],
                               ['S1', 'S2'])
    mc.add_multi_coupling_term(40., [1, 2, 3], ['X_1', 'Y_2', 'Y_3'],
                               ['Id', 'Id'])
    mc_des = {0: {('X_0', 'Id'): {1: {'Y_1': 0.125,
                                      ('Y_1', 'Id'): {3: {'Y_3': 20.0}}},
                                  2: {'Y_2': 0.25},
                                  3: {'Y_3': 0.375}},
                  ('X_0', 'S1'): {1: {('Y_1', 'S2'): {3: {'Y_3': 30.0}}}}},
              1: {('X_1', 'Id'): {2: {('Y_2', 'Id'): {3: {'Y_3': 40.0}}}}},
              2: {('X_2', 'Id'): {3: {'Y_3': 2.375}}}} # yapf: disable
    assert mc.coupling_terms == mc_des
    mc._test_terms(sites)
    # convert to TermList
    tl_mc = mc.to_TermList()
    term_list_des = [
        [('X_0', 0), ('Y_1', 1)],
        [('X_0', 0), ('Y_1', 1), ('Y_3', 3)],
        [('X_0', 0), ('Y_2', 2)],
        [('X_0', 0), ('Y_3', 3)],
        [('X_0', 0), ('Y_1', 1), ('Y_3', 3)],  # (!) droppend S1, S2 (!)
        [('X_1', 1), ('Y_2', 2), ('Y_3', 3)],
        [('X_2', 2), ('Y_3', 3)]
    ]
    assert tl_mc.terms == term_list_des
    assert np.all(tl_mc.strength == [0.125, 20., 0.25, 0.375, 30., 40., 2.375])
    ot, mc_conv = tl_mc.to_OnsiteTerms_CouplingTerms(sites)
    assert ot1.onsite_terms == [{}] * L
    del (mc_des[0])[('X_0', 'S1')]  # conversion dropped the opstring names
    mc_des[0][('X_0',
               'Id')][1][('Y_1',
                          'Id')][3]['Y_3'] += 30.  # add it to other term
    assert mc_conv.coupling_terms == mc_des

    # addition
    c2 = CouplingTerms(L)
    for i, j in [(0, 1), (1, 2)]:
        c1.add_coupling_term(strength1[i, j], i, j, "X_{i:d}".format(i=i),
                             "Y_{j:d}".format(j=j))
    c1 += c2
    c1_des = {0: {('X_0', 'Id'): {1: {'Y_1': 0.25},
                                  2: {'Y_2': 0.25},
                                  3: {'Y_3': 0.375}}},
              1: {('X_1', 'Id'): {2: {'Y_2': 1.25}}},
              2: {('X_2', 'Id'): {3: {'Y_3': 2.375}}}} # yapf: disable
    assert c1.coupling_terms == c1_des
    c1._test_terms(sites)
    mc += c1
    mc_des = {0: {('X_0', 'Id'): {1: {'Y_1': 0.375,
                                      ('Y_1', 'Id'): {3: {'Y_3': 20.0}}},
                                  2: {'Y_2': 0.5},
                                  3: {'Y_3': 0.75}},
                  ('X_0', 'S1'): {1: {('Y_1', 'S2'): {3: {'Y_3': 30.0}}}}},
              1: {('X_1', 'Id'): {2: {'Y_2': 1.25,
                                      ('Y_2', 'Id'): {3: {'Y_3': 40.0}}}}},
              2: {('X_2', 'Id'): {3: {'Y_3': 4.75}}}} # yapf: disable
    assert mc.coupling_terms == mc_des
    # coupling accross mps boundary
    mc.add_multi_coupling_term(50., [1, 3, 5], ['X_1', 'Y_3', 'Y_1'],
                               ['STR', 'JW'])
    assert mc.max_range() == 5 - 1
    mc._test_terms(sites)
    # remove the last coupling again
    mc.add_multi_coupling_term(-50., [1, 3, 5], ['X_1', 'Y_3', 'Y_1'],
                               ['STR', 'JW'])
    mc.remove_zeros()
    assert mc.coupling_terms == mc_des
    assert mc.max_range() == 3 - 0
Beispiel #2
0
def test_MPO_conversion():
    L = 8
    sites = []
    for i in range(L):
        s = site.Site(spin_half.leg)
        s.add_op("X_{i:d}".format(i=i), np.diag([2., 1.]))
        s.add_op("Y_{i:d}".format(i=i), np.diag([1., 2.]))
        sites.append(s)
    terms = [
        [("X_0", 0)],
        [("X_0", 0), ("X_1", 1)],
        [("X_0", 0), ("X_3", 3)],
        [("X_4", 4), ("Y_5", 5), ("Y_7", 7)],
        [("X_4", 4), ("Y_5", 5), ("X_7", 7)],
        [("X_4", 4), ("Y_6", 6), ("Y_7", 7)],
    ]
    prefactors = [0.25, 10., 11., 101., 102., 103.]
    term_list = TermList(terms, prefactors)
    g1 = mpo.MPOGraph.from_term_list(term_list,
                                     sites,
                                     bc='finite',
                                     insert_all_id=False)
    ct_add = MultiCouplingTerms(L)
    ct_add.add_coupling_term(12., 4, 5, "X_4", "X_5")
    ct_add.add_multi_coupling_term(0.5, [4, 5, 7], ["X_4", "Y_5", "X_7"], "Id")
    ct_add.add_to_graph(g1)
    H1 = g1.build_MPO()
    grids = [
        [['Id', 'X_0', [('X_0', 0.25)]]  # site 0
         ],
        [
            ['Id', None, None],  # site 1
            [None, 'Id', [('X_1', 10.0)]],
            [None, None, 'Id']
        ],
        [
            ['Id', None, None],  # site 2
            [None, [('Id', 11.0)], None],
            [None, None, 'Id']
        ],
        [
            ['Id', None],  # site 3
            [None, 'X_3'],
            [None, 'Id']
        ],
        [
            ['X_4', None],  #site 4
            [None, 'Id']
        ],
        [
            ['Id', 'Y_5', [('X_5', 12.0)]],  # site 5
            [None, None, 'Id']
        ],
        [
            # site 6
            [None, [('Y_6', 103.0)], None],
            [[('Id', 102.5)], [('Id', 101.0)], None],
            [None, None, 'Id']
        ],
        [
            ['X_7'],  # site 7
            ['Y_7'],
            ['Id']
        ]
    ]
    H2 = mpo.MPO.from_grids(sites, grids, 'finite', [0] * 4 + [None] * 5,
                            [None] * 5 + [-1] * 4)
    for w1, w2 in zip(H1._W, H2._W):
        assert npc.norm(w1 - w2, np.inf) == 0.
    pass