def test_gate_split_gate(self, propagate_tags):
p = MPS_rand_state(5, 7, tags={'PSI0'})
q = p.copy()
G = qu.CNOT()
p = p.gate_(G,
where=[i for i in range(2, 4)],
tags='G',
contract='split-gate',
propagate_tags=propagate_tags)
TG = sorted(p['G'], key=lambda t: sorted(t.tags))
if propagate_tags is False:
assert TG[0].tags == {'G'}
assert TG[1].tags == {'G'}
elif propagate_tags == 'register':
assert TG[0].tags == {'G', 'I2'}
assert TG[1].tags == {'G', 'I3'}
elif propagate_tags == 'sites':
assert TG[0].tags == {'G', 'I2', 'I3'}
assert TG[1].tags == {'G', 'I2', 'I3'}
elif propagate_tags is True:
assert TG[0].tags == {'PSI0', 'G', 'I2', 'I3'}
assert TG[1].tags == {'PSI0', 'G', 'I2', 'I3'}
assert (p.H & p) ^ all == pytest.approx(1.0)
assert abs((q.H & p) ^ all) < 1.0
assert len(p.tensors) == 7
assert set(p.outer_inds()) == {'k{}'.format(i) for i in range(5)}
def test_compress_trim_max_bond(self, method):
p0 = MPS_rand_state(20, 20)
p = p0.copy()
p.compress(method=method)
assert max(p['I4'].shape) == 20
p.compress(max_bond=13, method=method)
assert max(p['I4'].shape) == 13
assert_allclose(p.H @ p, p0.H @ p0)
def test_gate_no_contract(self, bsz, propagate_tags, contract):
p = MPS_rand_state(5, 7)
q = p.copy()
G = qu.rand_uni(2**bsz)
p = p.gate(G,
where=[i for i in range(2, 2 + bsz)],
tags='G',
contract=contract)
TG = p['G']
if propagate_tags or contract:
assert p.site_tag(2) in TG.tags
assert p.H @ p == pytest.approx(1.0)
assert abs(q.H @ p) < 1.0
assert len(p.tensors) == 6 - int(contract) * bsz
assert set(p.outer_inds()) == {'k{}'.format(i) for i in range(5)}
def test_insert_gauge(self, dtype):
k = MPS_rand_state(10, 7, dtype=dtype, normalize=False)
kU = k.copy()
U = rand_tensor((7, 7), dtype=dtype, inds='ab').data
kU.insert_gauge(U, 4, 5)
assert k[3].almost_equals(kU[3])
assert not k[4].almost_equals(kU[4])
assert not k[5].almost_equals(kU[5])
assert k[6].almost_equals(kU[6])
assert k[4].inds == kU[4].inds
assert k[5].inds == kU[5].inds
assert_allclose(k.H @ k, kU.H @ kU)
def test_gate_no_contract(self, bsz, propagate_tags, contract):
p = MPS_rand_state(5, 7, tags={'PSI0'})
q = p.copy()
G = qu.rand_uni(2**bsz)
p = p.gate_(G,
where=[i for i in range(2, 2 + bsz)],
tags='G',
contract=contract,
propagate_tags=propagate_tags)
TG = p['G']
if propagate_tags or contract:
assert p.site_tag(2) in TG.tags
assert ('PSI0' in TG.tags) == (propagate_tags is True) or contract
assert (p.H & p) ^ all == pytest.approx(1.0)
assert abs((q.H & p) ^ all) < 1.0
assert len(p.tensors) == 6 - int(contract) * bsz
assert set(p.outer_inds()) == {f'k{i}' for i in range(5)}
def test_gate2split(self):
psi = MPS_rand_state(10, 3)
psi2 = psi.copy()
G = qu.eye(2) & qu.eye(2)
psi.gate2split(G, (2, 3), cutoff=0)
assert psi.bond_size(2, 3) == 6
assert psi.H @ psi2 == pytest.approx(1.0)
# check a unitary application
G = qu.rand_uni(2**2)
psi.gate2split(G, (7, 8))
psi.compress()
assert psi.bond_size(2, 3) == 3
assert psi.bond_size(7, 8) > 3
assert psi.H @ psi == pytest.approx(1.0)
assert abs(psi2.H @ psi) < 1.0
# check matches dense application of gate
psid = psi2.to_dense()
Gd = qu.ikron(G, [2] * 10, (7, 8))
assert psi.to_dense().H @ (Gd @ psid) == pytest.approx(1.0)