def test_two_qubit_weyl_decomposition_bgate(self):
"""Verify Weyl KAK decomposition for U~B"""
for k1l, k1r, k2l, k2r in K1K2S:
k1 = np.kron(k1l.data, k1r.data)
k2 = np.kron(k2l.data, k2r.data)
a = Ud(np.pi / 4, np.pi / 8, 0)
self.check_two_qubit_weyl_decomposition(k1 @ a @ k2)
def check_two_qubit_weyl_decomposition(self,
target_unitary,
tolerance=1.e-7):
"""Check TwoQubitWeylDecomposition() works for a given operator"""
with self.subTest(unitary=target_unitary):
decomp = TwoQubitWeylDecomposition(target_unitary)
op = Operator(np.eye(4))
for u, qs in (
(decomp.K2r, [0]),
(decomp.K2l, [1]),
(Ud(decomp.a, decomp.b, decomp.c), [0, 1]),
(decomp.K1r, [0]),
(decomp.K1l, [1]),
):
op = op.compose(u, qs)
decomp_unitary = op.data
target_unitary *= la.det(target_unitary)**(-0.25)
decomp_unitary *= la.det(decomp_unitary)**(-0.25)
maxdists = [
np.max(np.abs(target_unitary + phase * decomp_unitary))
for phase in [1, 1j, -1, -1j]
]
maxdist = np.min(maxdists)
self.assertTrue(
np.abs(maxdist) < tolerance,
"Worst distance {}".format(maxdist))
def test_exact_supercontrolled_decompose_random(self, seeds):
"""Exact decomposition for random supercontrolled basis and random target"""
k1 = np.kron(random_unitary(2, seed=seeds[0]).data, random_unitary(2, seed=seeds[1]).data)
k2 = np.kron(random_unitary(2, seed=seeds[2]).data, random_unitary(2, seed=seeds[3]).data)
basis_unitary = k1 @ Ud(np.pi / 4, 0, 0) @ k2
decomposer = TwoQubitBasisDecomposer(UnitaryGate(basis_unitary))
self.check_exact_decomposition(random_unitary(4, seed=seeds[4]).data, decomposer)
def check_two_qubit_weyl_decomposition(self,
target_unitary,
tolerance=1.e-7):
"""Check TwoQubitWeylDecomposition() works for a given operator"""
with self.subTest(unitary=target_unitary):
decomp = TwoQubitWeylDecomposition(target_unitary)
q = QuantumRegister(2)
decomp_circuit = QuantumCircuit(q)
decomp_circuit.append(UnitaryGate(decomp.K2r), [q[0]])
decomp_circuit.append(UnitaryGate(decomp.K2l), [q[1]])
decomp_circuit.append(
UnitaryGate(Ud(decomp.a, decomp.b, decomp.c)), [q[0], q[1]])
decomp_circuit.append(UnitaryGate(decomp.K1r), [q[0]])
decomp_circuit.append(UnitaryGate(decomp.K1l), [q[1]])
result = execute(decomp_circuit, UnitarySimulatorPy()).result()
decomp_unitary = result.get_unitary()
target_unitary *= la.det(target_unitary)**(-0.25)
decomp_unitary *= la.det(decomp_unitary)**(-0.25)
maxdists = [
np.max(np.abs(target_unitary + phase * decomp_unitary))
for phase in [1, 1j, -1, -1j]
]
maxdist = np.min(maxdists)
self.assertTrue(
np.abs(maxdist) < tolerance,
"Worst distance {}".format(maxdist))
def test_exact_supercontrolled_decompose_random(self, seed):
"""Exact decomposition for random supercontrolled basis and random target (seed={seed})"""
# pylint: disable=invalid-name
k1 = np.kron(random_unitary(2, seed=seed).data, random_unitary(2, seed=seed + 1).data)
k2 = np.kron(random_unitary(2, seed=seed + 2).data, random_unitary(2, seed=seed + 3).data)
basis_unitary = k1 @ Ud(np.pi / 4, 0, 0) @ k2
decomposer = TwoQubitBasisDecomposer(UnitaryGate(basis_unitary))
self.check_exact_decomposition(random_unitary(4, seed=seed + 4).data, decomposer)
def test_exact_supercontrolled_decompose_random(self, nsamples=10):
"""Verify exact decomposition for random supercontrolled basis and random target"""
for _ in range(nsamples):
k1 = np.kron(random_unitary(2).data, random_unitary(2).data)
k2 = np.kron(random_unitary(2).data, random_unitary(2).data)
basis_unitary = k1 @ Ud(np.pi / 4, 0, 0) @ k2
decomposer = TwoQubitBasisDecomposer(UnitaryGate(basis_unitary))
self.check_exact_decomposition(random_unitary(4).data, decomposer)
def test_two_qubit_weyl_decomposition_aama(self, smallest=1e-18, factor=9.8, steps=11):
"""Verify Weyl KAK decomposition for U~Ud(a,a,-a)"""
for aaa in ([smallest * factor ** i for i in range(steps)] +
[np.pi / 4 - smallest * factor ** i for i in range(steps)] +
[np.pi / 8, 0.113 * np.pi, 0.1972 * np.pi]):
for k1l, k1r, k2l, k2r in K1K2S:
k1 = np.kron(k1l.data, k1r.data)
k2 = np.kron(k2l.data, k2r.data)
a = Ud(aaa, aaa, -aaa)
self.check_two_qubit_weyl_decomposition(k1 @ a @ k2)
def check_two_qubit_weyl_decomposition(self,
target_unitary,
tolerance=1.e-7):
"""Check TwoQubitWeylDecomposition() works for a given operator"""
# pylint: disable=invalid-name
decomp = TwoQubitWeylDecomposition(target_unitary)
op = np.exp(1j * decomp.global_phase) * Operator(np.eye(4))
for u, qs in (
(decomp.K2r, [0]),
(decomp.K2l, [1]),
(Ud(decomp.a, decomp.b, decomp.c), [0, 1]),
(decomp.K1r, [0]),
(decomp.K1l, [1]),
):
op = op.compose(u, qs)
decomp_unitary = op.data
maxdist = np.max(np.abs(target_unitary - decomp_unitary))
self.assertTrue(
np.abs(maxdist) < tolerance,
"Unitary {}: Worst distance {}".format(target_unitary, maxdist))
def test_exact_nonsupercontrolled_decompose(self):
"""Check that the nonsupercontrolled basis throws a warning"""
with self.assertWarns(UserWarning, msg="Supposed to warn when basis non-supercontrolled"):
TwoQubitBasisDecomposer(UnitaryGate(Ud(np.pi / 4, 0.2, 0.1)))
