def test_big_gates(self):
"""Test large gates with params"""
qr = QuantumRegister(6, "q")
circuit = QuantumCircuit(qr)
circuit.append(IQP([[6, 5, 3], [5, 4, 5], [3, 5, 1]]), [0, 1, 2])
desired_vector = [
1 / math.sqrt(16) * complex(0, 1),
1 / math.sqrt(8) * complex(1, 0),
1 / math.sqrt(16) * complex(1, 1),
0,
0,
1 / math.sqrt(8) * complex(1, 2),
1 / math.sqrt(16) * complex(1, 0),
0,
]
circuit.initialize(desired_vector, [qr[3], qr[4], qr[5]])
circuit.unitary([[1, 0], [0, 1]], [qr[0]])
matrix = np.zeros((4, 4))
theta = Parameter("theta")
circuit.append(HamiltonianGate(matrix, theta), [qr[1], qr[2]])
circuit = circuit.bind_parameters({theta: 1})
circuit.isometry(np.eye(4, 4), list(range(3, 5)), [])
self.circuit_drawer(circuit, filename="big_gates.png")
def test_big_gates(self):
"""Test large gates with params"""
filename = self._get_resource_path('test_latex_big_gates.tex')
qr = QuantumRegister(6, 'q')
circuit = QuantumCircuit(qr)
circuit.append(IQP([[6, 5, 3], [5, 4, 5], [3, 5, 1]]), [0, 1, 2])
desired_vector = [
1 / math.sqrt(16) * complex(0, 1),
1 / math.sqrt(8) * complex(1, 0),
1 / math.sqrt(16) * complex(1, 1),
0,
0,
1 / math.sqrt(8) * complex(1, 2),
1 / math.sqrt(16) * complex(1, 0),
0]
circuit.initialize(desired_vector, [qr[3], qr[4], qr[5]])
circuit.unitary([[1, 0], [0, 1]], [qr[0]])
matrix = np.zeros((4, 4))
theta = Parameter('theta')
circuit.append(HamiltonianGate(matrix, theta), [qr[1], qr[2]])
circuit = circuit.bind_parameters({theta: 1})
circuit.isometry(np.eye(4, 4), list(range(3, 5)), [])
circuit_drawer(circuit, filename=filename, output='latex_source')
self.assertEqualToReference(filename)
def ad_hoc_hhl(A, t0, r):
reg_b = QuantumRegister(2)
reg_c = QuantumRegister(4)
ancil = QuantumRegister(1)
circ = QuantumCircuit(reg_b, reg_c, ancil)
circ.append(quantum_phase_estimation(2, 4, HamiltonianGate(A, t0 / 16)),
range(6))
circ.swap(reg_c[1], reg_c[3])
for i in range(4):
circ.cry(np.pi * (2**(4 - i - r)), reg_c[i], ancil[0])
circ.barrier()
circ.swap(reg_c[1], reg_c[3])
circ.append(
quantum_phase_estimation(2, 4, HamiltonianGate(A, t0 / 16)).inverse(),
range(6))
return circ
def build_varckt(self):
# Build variational circuit
circ = QuantumCircuit(self.n)
circ.h(range(self.n))
for i in range(self.p):
eC = QuantumCircuit(self.n,
name='$U(C,\\gamma_' + str(i + 1) + ')$')
eC.append(HamiltonianGate(self.C, self.gamma[i]), range(self.n))
eB = QuantumCircuit(self.n,
name='$U(B,\\beta_' + str(i + 1) + ')$')
eB.rx(2 * self.beta[i], range(self.n))
circ.append(eC.to_gate(), range(self.n))
circ.append(eB.to_gate(), range(self.n))
circ.measure_all()
return circ
def hhl_forward_ckt(n, t, m, l, A, t0, vis=False):
reg_b = QuantumRegister(n, name='b')
reg_c = QuantumRegister(t, name='c')
reg_m = QuantumRegister(m, name='m')
reg_l = QuantumRegister(l, name='l')
temp = QuantumCircuit(reg_b, name='$U$')
temp.append(HamiltonianGate(A, t0 / (2**t)), reg_b)
circ = QuantumCircuit(reg_b, reg_c, reg_m, reg_l, name='$Fwd$')
circ.append(quantum_phase_estimation(n, t, temp.to_gate(), vis=vis),
range(n + t))
circ.h(reg_m)
circ.h(reg_l)
for i in range(m):
circ.rz(t0 / (2**(m - i)), reg_m[i])
circ.append(subroutine_b(t, m, l, t0, vis=vis), range(n, n + t + m + l))
if vis:
circ.draw('mpl', reverse_bits=True, style={'fontsize': 6, 'subfontsize': 3})\
.suptitle('HHL Forward Computation', fontsize=16)
return circ.to_gate()
def get_loss(
self,
hamiltonian: OperatorBase,
ansatz: QuantumCircuit,
dt: float,
current_parameters: np.ndarray,
) -> Tuple[Callable[[np.ndarray], float], Optional[Callable[[np.ndarray], np.ndarray]]]:
"""Get a function to evaluate the infidelity between Trotter step and ansatz.
Args:
hamiltonian: The Hamiltonian under which to evolve.
ansatz: The parameterized quantum circuit which attempts to approximate the
time-evolved state.
dt: The time step.
current_parameters: The current parameters.
Returns:
A callable to evaluate the infidelity and, if gradients are supported and required,
a second callable to evaluate the gradient of the infidelity.
"""
self._validate_setup(skip={"optimizer"})
# use Trotterization to evolve the current state
trotterized = ansatz.bind_parameters(current_parameters)
if isinstance(hamiltonian, MatrixOp):
evolution_gate = HamiltonianGate(hamiltonian.primitive, time=dt)
else:
evolution_gate = PauliEvolutionGate(hamiltonian, time=dt, synthesis=self.evolution)
trotterized.append(evolution_gate, ansatz.qubits)
# define the overlap of the Trotterized state and the ansatz
x = ParameterVector("w", ansatz.num_parameters)
shifted = ansatz.assign_parameters(current_parameters + x)
overlap = StateFn(trotterized).adjoint() @ StateFn(shifted)
converted = self.expectation.convert(overlap)
def evaluate_loss(
displacement: Union[np.ndarray, List[np.ndarray]]
) -> Union[float, List[float]]:
"""Evaluate the overlap of the ansatz with the Trotterized evolution.
Args:
displacement: The parameters for the ansatz.
Returns:
The fidelity of the ansatz with parameters ``theta`` and the Trotterized evolution.
"""
if isinstance(displacement, list):
displacement = np.asarray(displacement)
value_dict = {x_i: displacement[:, i].tolist() for i, x_i in enumerate(x)}
else:
value_dict = dict(zip(x, displacement))
sampled = self._sampler.convert(converted, params=value_dict)
# in principle we could add different loss functions here, but we're currently
# not aware of a use-case for a different one than in the paper
return 1 - np.abs(sampled.eval()) ** 2
if _is_gradient_supported(ansatz) and self.use_parameter_shift:
def evaluate_gradient(displacement: np.ndarray) -> np.ndarray:
"""Evaluate the gradient with the parameter-shift rule.
This is hardcoded here since the gradient framework does not support computing
gradients for overlaps.
Args:
displacement: The parameters for the ansatz.
Returns:
The gradient.
"""
# construct lists where each element is shifted by plus (or minus) pi/2
dim = displacement.size
plus_shifts = (displacement + np.pi / 2 * np.identity(dim)).tolist()
minus_shifts = (displacement - np.pi / 2 * np.identity(dim)).tolist()
evaluated = evaluate_loss(plus_shifts + minus_shifts)
gradient = (evaluated[:dim] - evaluated[dim:]) / 2
return gradient
else:
evaluate_gradient = None
return evaluate_loss, evaluate_gradient