def test_one_qubit_wavefunction_circuit(self, device, qvm, compiler):
"""Test that the wavefunction plugin provides correct result for simple circuit.
As the results coming from the qvm are stochastic, a constraint of 2 out of 5 runs was added.
"""
shots = 100_000
dev = qml.device("forest.qvm", device=device, shots=QVM_SHOTS)
a = 0.543
b = 0.123
c = 0.987
@qml.qnode(dev)
def circuit(x, y, z):
"""Reference QNode"""
qml.BasisState(np.array([1]), wires=0)
qml.Hadamard(wires=0)
qml.Rot(x, y, z, wires=0)
return qml.expval(qml.PauliZ(0))
self.assertAlmostEqual(circuit(a, b, c), np.cos(a) * np.sin(b), delta=3 / np.sqrt(shots))
def test_state_differentiability(self, tol):
"""Test that the device state can be differentiated"""
dev = qml.device("default.qubit.autograd", wires=1)
@qml.qnode(dev, diff_method="backprop", interface="autograd")
def circuit(a):
qml.RY(a, wires=0)
return qml.expval(qml.PauliZ(0))
a = np.array(0.54, requires_grad=True)
def cost(a):
"""A function of the device quantum state, as a function
of input QNode parameters."""
circuit(a)
res = np.abs(dev.state)**2
return res[1] - res[0]
grad = qml.grad(cost)(a)
expected = np.sin(a)
assert np.allclose(grad, expected, atol=tol, rtol=0)
def test_beamsplitter(self):
"""Test the beamsplitter symplectic transform."""
self.logTestName()
theta = 0.543
phi = 0.312
S = beamsplitter(theta, phi)
# apply to a coherent state. BS|a1, a2> -> |ta1-r^*a2, ra1+ta2>
a1 = 0.23 + 0.12j
a2 = 0.23 + 0.12j
out = S @ np.array([a1.real, a2.real, a1.imag, a2.imag]) * np.sqrt(
2 * hbar)
T = np.cos(theta)
R = np.exp(1j * phi) * np.sin(theta)
a1out = T * a1 - R.conj() * a2
a2out = R * a2 + T * a1
expected = np.array([a1out.real, a2out.real, a1out.imag, a2out.imag
]) * np.sqrt(2 * hbar)
self.assertAllAlmostEqual(out, expected, delta=self.tol)
def test_matrix_parameter(self, mocker, tol):
"""Test jacobian computation when the tape includes a matrix parameter"""
spy = mocker.spy(QuantumTape, "jacobian")
U = np.array([[0, 1], [1, 0]], requires_grad=False)
a = np.array(0.1, requires_grad=True)
def cost(a, U, device):
with QuantumTape() as tape:
qml.QubitUnitary(U, wires=0)
qml.RY(a, wires=0)
expval(qml.PauliZ(0))
return tape.execute(device)
dev = qml.device("default.qubit.autograd", wires=2)
res = cost(a, U, device=dev)
assert np.allclose(res, -np.cos(a), atol=tol, rtol=0)
jac_fn = qml.jacobian(cost)
res = jac_fn(a, U, device=dev)
assert np.allclose(res, np.sin(a), atol=tol, rtol=0)
spy.assert_not_called()
def test_pauliy_expectation(self, shots, qvm, compiler):
"""Test that PauliY expectation value is correct"""
theta = 0.432
phi = 0.123
dev = plf.QVMDevice(device="2q-qvm", shots=shots)
dev.apply("RX", wires=[0], par=[theta])
dev.apply("RX", wires=[1], par=[phi])
dev.apply("CNOT", wires=[0, 1], par=[])
O = qml.PauliY
name = "PauliY"
dev._obs_queue = [O(wires=[0], do_queue=False), O(wires=[1], do_queue=False)]
dev.pre_measure()
# below are the analytic expectation values for this circuit
res = np.array([dev.expval(name, [0], []), dev.expval(name, [1], [])])
self.assertAllAlmostEqual(
res, np.array([0, -np.cos(theta) * np.sin(phi)]), delta=3 / np.sqrt(shots)
)
def test_matrix_parameter(self, tol):
"""Test that the autograd interface works correctly
with a matrix parameter"""
U = np.array([[0, 1], [1, 0]], requires_grad=False)
a = np.array(0.1, requires_grad=True)
def cost(a, U, device):
with AutogradInterface.apply(QuantumTape()) as tape:
qml.QubitUnitary(U, wires=0)
qml.RY(a, wires=0)
expval(qml.PauliZ(0))
assert tape.trainable_params == {1}
return tape.execute(device)
dev = qml.device("default.qubit", wires=2)
res = cost(a, U, device=dev)
assert np.allclose(res, -np.cos(a), atol=tol, rtol=0)
jac_fn = qml.jacobian(cost)
res = jac_fn(a, U, device=dev)
assert np.allclose(res, np.sin(a), atol=tol, rtol=0)
def test_matrix_parameter(self, dev_name, diff_method, tol):
"""Test that the autograd interface works correctly
with a matrix parameter"""
U = np.array([[0, 1], [1, 0]], requires_grad=False)
a = np.array(0.1, requires_grad=True)
dev = qml.device(dev_name, wires=2)
@qnode(dev, diff_method=diff_method, interface="autograd")
def circuit(U, a):
qml.QubitUnitary(U, wires=0)
qml.RY(a, wires=0)
return qml.expval(qml.PauliZ(0))
res = circuit(U, a)
if diff_method == "finite-diff":
assert circuit.qtape.trainable_params == {1}
res = qml.grad(circuit)(U, a)
assert np.allclose(res, np.sin(a), atol=tol, rtol=0)
def test_parameter_shift_hessian(self, params, tol, recwarn):
"""Tests that the output of the parameter-shift transform
can be differentiated using autograd, yielding second derivatives."""
dev = qml.device("default.qubit.autograd", wires=2)
params = np.array([0.543, -0.654], requires_grad=True)
def cost_fn(x):
with qml.tape.JacobianTape() as tape1:
qml.RX(x[0], wires=[0])
qml.RY(x[1], wires=[1])
qml.CNOT(wires=[0, 1])
qml.var(qml.PauliZ(0) @ qml.PauliX(1))
with qml.tape.JacobianTape() as tape2:
qml.RX(x[0], wires=0)
qml.RY(x[0], wires=1)
qml.CNOT(wires=[0, 1])
qml.probs(wires=1)
result = execute([tape1, tape2],
dev,
gradient_fn=param_shift,
max_diff=2)
return result[0] + result[1][0, 0]
res = cost_fn(params)
x, y = params
expected = 0.5 * (3 + np.cos(x)**2 * np.cos(2 * y))
assert np.allclose(res, expected, atol=tol, rtol=0)
res = qml.grad(cost_fn)(params)
expected = np.array([
-np.cos(x) * np.cos(2 * y) * np.sin(x),
-np.cos(x)**2 * np.sin(2 * y)
])
assert np.allclose(res, expected, atol=tol, rtol=0)
res = qml.jacobian(qml.grad(cost_fn))(params)
expected = np.array([
[-np.cos(2 * x) * np.cos(2 * y),
np.sin(2 * x) * np.sin(2 * y)],
[np.sin(2 * x) * np.sin(2 * y), -2 * np.cos(x)**2 * np.cos(2 * y)],
])
assert np.allclose(res, expected, atol=tol, rtol=0)
# Check that no deprecation warnigns are emitted due to trainable
# parameters with the Autograd interface
assert len(recwarn) == 0
def test_multiple_expectation_values(self, tol, dev):
"""Tests correct output shape and evaluation for a tape
with multiple expval outputs"""
x = 0.543
y = -0.654
with qml.tape.QuantumTape() as tape:
qml.RX(x, wires=[0])
qml.RY(y, wires=[1])
qml.CNOT(wires=[0, 1])
qml.expval(qml.PauliZ(0))
qml.expval(qml.PauliX(1))
tape.trainable_params = {0, 1}
dy = np.array([1.0, 2.0])
fn = dev.vjp(tape.measurements, dy)
vjp = fn(tape)
expected = np.array([-np.sin(x), 2 * np.cos(y)])
assert np.allclose(vjp, expected, atol=tol, rtol=0)
def test_hessian_unused_parameter(self, dev_name, diff_method, mocker,
tol):
"""Test hessian calculation of a scalar valued QNode"""
if diff_method not in {"parameter-shift", "backprop"}:
pytest.skip("Test only supports parameter-shift or backprop")
dev = qml.device(dev_name, wires=1)
@qnode(dev, diff_method=diff_method, interface="autograd")
def circuit(x):
qml.RY(x[0], wires=0)
return qml.expval(qml.PauliZ(0))
x = np.array([1.0, 2.0], requires_grad=True)
res = circuit(x)
a, b = x
expected_res = np.cos(a)
assert np.allclose(res, expected_res, atol=tol, rtol=0)
grad_fn = qml.grad(circuit)
g = grad_fn(x)
expected_g = [-np.sin(a), 0]
assert np.allclose(g, expected_g, atol=tol, rtol=0)
spy = mocker.spy(JacobianTape, "hessian")
hess = qml.jacobian(grad_fn)(x)
if diff_method == "backprop":
spy.assert_not_called()
elif diff_method == "parameter-shift":
spy.assert_called_once()
expected_hess = [
[-np.cos(a), 0],
[0, 0],
]
assert np.allclose(hess, expected_hess, atol=tol, rtol=0)
def test_probability_differentiation(self, execute_kwargs, tol):
"""Tests correct output shape and evaluation for a tape
with prob outputs"""
if execute_kwargs["gradient_fn"] == "device":
pytest.skip(
"Adjoint differentiation does not yet support probabilities")
def cost(x, y, device):
with qml.tape.JacobianTape() as tape:
qml.RX(x, wires=[0])
qml.RY(y, wires=[1])
qml.CNOT(wires=[0, 1])
qml.probs(wires=[0])
qml.probs(wires=[1])
return execute([tape], device, **execute_kwargs)[0]
dev = qml.device("default.qubit", wires=2)
x = np.array(0.543, requires_grad=True)
y = np.array(-0.654, requires_grad=True)
res = cost(x, y, device=dev)
expected = np.array([
[np.cos(x / 2)**2, np.sin(x / 2)**2],
[(1 + np.cos(x) * np.cos(y)) / 2, (1 - np.cos(x) * np.cos(y)) / 2],
])
assert np.allclose(res, expected, atol=tol, rtol=0)
jac_fn = qml.jacobian(cost)
res = jac_fn(x, y, device=dev)
assert res.shape == (2, 2, 2)
expected = np.array([
[[-np.sin(x) / 2, 0], [np.sin(x) / 2, 0]],
[
[-np.sin(x) * np.cos(y) / 2, -np.cos(x) * np.sin(y) / 2],
[np.cos(y) * np.sin(x) / 2,
np.cos(x) * np.sin(y) / 2],
],
])
assert np.allclose(res, expected, atol=tol, rtol=0)
def test_probability_differentiation(self, mocker, tol):
"""Tests correct output shape and evaluation for a tape
with prob and expval outputs"""
spy = mocker.spy(QuantumTape, "jacobian")
def cost(x, y, device):
with QuantumTape() as tape:
qml.RX(x, wires=[0])
qml.RY(y, wires=[1])
qml.CNOT(wires=[0, 1])
probs(wires=[0])
probs(wires=[1])
return tape.execute(device)
dev = qml.device("default.qubit.autograd", wires=2)
x = np.array(0.543, requires_grad=True)
y = np.array(-0.654, requires_grad=True)
res = cost(x, y, device=dev)
expected = np.array([
[np.cos(x / 2)**2, np.sin(x / 2)**2],
[(1 + np.cos(x) * np.cos(y)) / 2, (1 - np.cos(x) * np.cos(y)) / 2],
])
assert np.allclose(res, expected, atol=tol, rtol=0)
jac_fn = qml.jacobian(cost)
res = jac_fn(x, y, device=dev)
assert res.shape == (2, 2, 2)
expected = np.array([
[[-np.sin(x) / 2, 0],
[-np.sin(x) * np.cos(y) / 2, -np.cos(x) * np.sin(y) / 2]],
[
[np.sin(x) / 2, 0],
[np.cos(y) * np.sin(x) / 2,
np.cos(x) * np.sin(y) / 2],
],
])
assert np.allclose(res, expected, atol=tol, rtol=0)
spy.assert_not_called()
def test_multiple_expectation_values(self, approx_order, strategy, tol):
"""Tests correct output shape and evaluation for a tape
with multiple expval outputs"""
dev = qml.device("default.qubit", wires=2)
x = 0.543
y = -0.654
with qml.tape.JacobianTape() as tape:
qml.RX(x, wires=[0])
qml.RY(y, wires=[1])
qml.CNOT(wires=[0, 1])
qml.expval(qml.PauliZ(0))
qml.expval(qml.PauliX(1))
tapes, fn = finite_diff(tape,
approx_order=approx_order,
strategy=strategy)
res = fn(dev.batch_execute(tapes))
assert res.shape == (2, 2)
expected = np.array([[-np.sin(x), 0], [0, np.cos(y)]])
assert np.allclose(res, expected, atol=tol, rtol=0)
def test_get_unitary_matrix_tensorflow_differentiable(v):
tf = pytest.importorskip("tensorflow")
def circuit(theta):
qml.RX(theta, wires=0)
qml.PauliZ(wires=0)
qml.CNOT(wires=[0, 1])
def loss(theta):
U = qml.transforms.get_unitary_matrix(circuit)(theta)
return qml.math.real(qml.math.trace(U))
x = tf.Variable(v)
with tf.GradientTape() as tape:
l = loss(x)
dl = tape.gradient(l, x)
matrix = qml.transforms.get_unitary_matrix(circuit)(x)
assert isinstance(matrix, tf.Tensor)
assert np.allclose(l, 2 * np.cos(v / 2))
assert np.allclose(dl, -np.sin(v / 2))
def test_get_unitary_matrix_torch_differentiable(v):
torch = pytest.importorskip("torch")
def circuit(theta):
qml.RX(theta, wires=0)
qml.PauliZ(wires=0)
qml.CNOT(wires=[0, 1])
def loss(theta):
U = qml.transforms.get_unitary_matrix(circuit)(theta)
return qml.math.real(qml.math.trace(U))
x = torch.tensor(v, requires_grad=True)
l = loss(x)
l.backward()
dl = x.grad
matrix = qml.transforms.get_unitary_matrix(circuit)(x)
assert isinstance(matrix, torch.Tensor)
assert np.allclose(l.detach(), 2 * np.cos(v / 2))
assert np.allclose(dl.detach(), -np.sin(v / 2))
def test_get_unitary_matrix_jax_differentiable(v):
jax = pytest.importorskip("jax")
def circuit(theta):
qml.RX(theta, wires=0)
qml.PauliZ(wires=0)
qml.CNOT(wires=[0, 1])
def loss(theta):
U = qml.transforms.get_unitary_matrix(circuit)(theta)
return qml.math.real(qml.math.trace(U))
x = jax.numpy.array(v)
l = loss(x)
dl = jax.grad(loss)(x)
matrix = qml.transforms.get_unitary_matrix(circuit)(x)
assert isinstance(matrix, jax.numpy.ndarray)
assert np.allclose(l, 2 * np.cos(v / 2))
assert np.allclose(dl, -np.sin(v / 2))
def test_multiple_rx_gradient(self, tol):
"""Tests that the gradient of multiple RX gates in a circuit
yeilds the correct result."""
dev = qml.device("default.qubit", wires=3)
params = np.array([np.pi, np.pi / 2, np.pi / 3])
with ReversibleTape() as tape:
qml.RX(params[0], wires=0)
qml.RX(params[1], wires=1)
qml.RX(params[2], wires=2)
for idx in range(3):
qml.expval(qml.PauliZ(idx))
circuit_output = tape.execute(dev)
expected_output = np.cos(params)
assert np.allclose(circuit_output, expected_output, atol=tol, rtol=0)
# circuit jacobians
circuit_jacobian = tape.jacobian(dev, method="analytic")
expected_jacobian = -np.diag(np.sin(params))
assert np.allclose(circuit_jacobian, expected_jacobian, atol=tol, rtol=0)
def test_multiple_probability_differentiation(self, dev_name, diff_method,
tol):
"""Tests correct output shape and evaluation for a tape
with multiple prob outputs"""
if diff_method == "adjoint":
pytest.skip(
"The adjoint method does not currently support returning probabilities"
)
dev = qml.device(dev_name, wires=2)
x = np.array(0.543, requires_grad=True)
y = np.array(-0.654, requires_grad=True)
@qnode(dev, diff_method=diff_method, interface="autograd")
def circuit(x, y):
qml.RX(x, wires=[0])
qml.RY(y, wires=[1])
qml.CNOT(wires=[0, 1])
return qml.probs(wires=[0]), qml.probs(wires=[1])
res = circuit(x, y)
expected = np.array([
[np.cos(x / 2)**2, np.sin(x / 2)**2],
[(1 + np.cos(x) * np.cos(y)) / 2, (1 - np.cos(x) * np.cos(y)) / 2],
])
assert np.allclose(res, expected, atol=tol, rtol=0)
res = qml.jacobian(circuit)(x, y)
expected = np.array([
[[-np.sin(x) / 2, 0],
[-np.sin(x) * np.cos(y) / 2, -np.cos(x) * np.sin(y) / 2]],
[
[np.sin(x) / 2, 0],
[np.cos(y) * np.sin(x) / 2,
np.cos(x) * np.sin(y) / 2],
],
])
assert np.allclose(res, expected, atol=tol, rtol=0)
def test_classical_processing_arguments(self, mocker, tol):
"""Test that a gradient transform acts on QNodes
correctly when the QNode arguments are classically processed"""
dev = qml.device("default.qubit", wires=2)
spy = mocker.spy(qml.transforms, "classical_jacobian")
@qml.qnode(dev)
def circuit(weights):
qml.RX(weights[0] ** 2, wires=[0])
qml.RY(weights[1], wires=[1])
qml.CNOT(wires=[0, 1])
return qml.expval(qml.PauliZ(0))
w = np.array([0.543, -0.654], requires_grad=True)
res = qml.gradients.param_shift(circuit)(w)
classical_jac = spy.spy_return(w)
assert isinstance(classical_jac, np.ndarray)
assert np.allclose(classical_jac, np.array([[2 * w[0], 0], [0, 1]]))
x, y = w
expected = [-2 * x * np.sin(x ** 2), 0]
assert np.allclose(res, expected, atol=tol, rtol=0)
def test_classical_processing(self, dev_name, diff_method, tol):
"""Test classical processing within the quantum tape"""
a = np.array(0.1, requires_grad=True)
b = np.array(0.2, requires_grad=False)
c = np.array(0.3, requires_grad=True)
dev = qml.device(dev_name, wires=1)
@qnode(dev, diff_method=diff_method, interface="autograd")
def circuit(a, b, c):
qml.RY(a * c, wires=0)
qml.RZ(b, wires=0)
qml.RX(c + c ** 2 + np.sin(a), wires=0)
return qml.expval(qml.PauliZ(0))
res = qml.jacobian(circuit)(a, b, c)
if diff_method == "finite-diff":
assert circuit.qtape.trainable_params == {0, 2}
tape_params = np.array(circuit.qtape.get_parameters())
assert np.all(tape_params == [a * c, c + c ** 2 + np.sin(a)])
assert res.shape == (2,)
def test_nonzero_shots(self, qvm, compiler):
"""Test that the wavefunction plugin provides correct result for high shot number"""
shots = 10**2
dev = qml.device('forest.wavefunction', wires=1, shots=shots)
a = 0.543
b = 0.123
c = 0.987
@qml.qnode(dev)
def circuit(x, y, z):
"""Test QNode"""
qml.BasisState(np.array([1]), wires=0)
qml.Hadamard(wires=0)
qml.Rot(x, y, z, wires=0)
return qml.expval.PauliZ(0)
runs = []
for _ in range(100):
runs.append(circuit(a, b, c))
expected_var = np.sqrt(1/shots)
self.assertAlmostEqual(np.mean(runs), np.cos(a)*np.sin(b), delta=expected_var)
def test_probability_differentiation(self, tol):
"""Tests correct output shape and evaluation for a tape
with prob outputs"""
def cost(x, y, device):
with AutogradInterface.apply(JacobianTape()) as tape:
qml.RX(x, wires=[0])
qml.RY(y, wires=[1])
qml.CNOT(wires=[0, 1])
qml.probs(wires=[0])
qml.probs(wires=[1])
return tape.execute(device)
dev = qml.device("default.qubit", wires=2)
x = np.array(0.543, requires_grad=True)
y = np.array(-0.654, requires_grad=True)
res = cost(x, y, device=dev)
expected = np.array(
[
[np.cos(x / 2) ** 2, np.sin(x / 2) ** 2],
[(1 + np.cos(x) * np.cos(y)) / 2, (1 - np.cos(x) * np.cos(y)) / 2],
]
)
assert np.allclose(res, expected, atol=tol, rtol=0)
jac_fn = qml.jacobian(cost)
res = jac_fn(x, y, device=dev)
assert res.shape == (2, 2, 2)
expected = np.array(
[
[[-np.sin(x) / 2, 0], [-np.sin(x) * np.cos(y) / 2, -np.cos(x) * np.sin(y) / 2]],
[
[np.sin(x) / 2, 0],
[np.cos(y) * np.sin(x) / 2, np.cos(x) * np.sin(y) / 2],
],
]
)
assert np.allclose(res, expected, atol=tol, rtol=0)
def test_pauliy_expectation(self, shots, qvm, compiler):
"""Test that PauliY expectation value is correct"""
theta = 0.432
phi = 0.123
dev = plf.QVMDevice(device="2q-qvm", shots=shots)
with qml.tape.QuantumTape() as tape:
qml.RX(theta, wires=[0])
qml.RX(phi, wires=[1])
qml.CNOT(wires=[0, 1])
O1 = qml.expval(qml.PauliY(wires=[0]))
O2 = qml.expval(qml.PauliY(wires=[1]))
dev.apply(tape.operations, rotations=tape.diagonalizing_gates)
dev._samples = dev.generate_samples()
res = np.array([dev.expval(O1.obs), dev.expval(O2.obs)])
# below are the analytic expectation values for this circuit
self.assertAllAlmostEqual(res,
np.array([0, -np.cos(theta) * np.sin(phi)]),
delta=3 / np.sqrt(shots))
def cost(*p):
with qml.tape.QuantumTape() as tape:
qml.RX(p[0][0], wires=0)
qml.RY(p[1], wires=0)
qml.PhaseShift(p[0][1], wires=0)
qml.RZ(p[0][2], wires=0)
params = tape.get_parameters(trainable_only=False)
tape.trainable_params = qml.math.get_trainable_indices(params)
with tape.unwrap() as unwrapped_tape:
# inside the context manager, all parameters
# will be unwrapped to NumPy arrays
params = tape.get_parameters(trainable_only=False)
assert all(isinstance(i, float) for i in params)
assert np.allclose(params, [0.1, 0.2, 0.5, 0.3])
assert tape.trainable_params == [0, 2, 3]
# outside the context, the original parameters have been restored.
params = tape.get_parameters(trainable_only=False)
assert any(isinstance(i, ArrayBox) for i in params)
return p[0][0] * p[1]**2 * anp.sin(p[0][1]) * anp.exp(-0.5 * p[0][2])
def test_torch(self, tol):
"""Test that a gradient transform remains differentiable
with PyTorch"""
torch = pytest.importorskip("torch")
dev = qml.device("default.qubit", wires=2)
@qml.gradients.param_shift
@qml.qnode(dev, interface="torch")
def circuit(x):
qml.RY(x, wires=[1])
qml.CNOT(wires=[0, 1])
return qml.var(qml.PauliX(1))
x_ = -0.654
x = torch.tensor(x_, dtype=torch.float64, requires_grad=True)
res = circuit(x)[0]
expected = -2 * np.cos(x_) * np.sin(x_)
assert np.allclose(res.detach(), expected, atol=tol, rtol=0)
res.backward()
expected = -2 * np.cos(2 * x_)
assert np.allclose(x.grad.detach(), expected, atol=tol, rtol=0)
def test_multiple_probability_differentiation(self, dev_name, diff_method, mode, tol):
"""Tests correct output shape and evaluation for a tape
with multiple prob outputs"""
if diff_method != "backprop":
pytest.skip("JAX interface does not support vector-valued QNodes")
dev = qml.device(dev_name, wires=2)
x = jnp.array(0.543)
y = jnp.array(-0.654)
@qnode(dev, diff_method=diff_method, interface="jax", mode=mode)
def circuit(x, y):
qml.RX(x, wires=[0])
qml.RY(y, wires=[1])
qml.CNOT(wires=[0, 1])
return qml.probs(wires=[0]), qml.probs(wires=[1])
res = circuit(x, y)
expected = np.array(
[
[np.cos(x / 2) ** 2, np.sin(x / 2) ** 2],
[(1 + np.cos(x) * np.cos(y)) / 2, (1 - np.cos(x) * np.cos(y)) / 2],
]
)
assert np.allclose(res, expected, atol=tol, rtol=0)
res = jax.jacobian(circuit, argnums=[0, 1])(x, y)
expected = np.array(
[
[[-np.sin(x) / 2, 0], [-np.sin(x) * np.cos(y) / 2, -np.cos(x) * np.sin(y) / 2]],
[
[np.sin(x) / 2, 0],
[np.cos(y) * np.sin(x) / 2, np.cos(x) * np.sin(y) / 2],
],
]
)
assert np.allclose(res, expected.T, atol=tol, rtol=0)
def test_pauliy_expectation(self, shots):
"""Test that PauliY expectation value is correct"""
theta = 0.432
phi = 0.123
dev = plf.QVMDevice(device='2q-pyqvm', shots=shots)
dev.apply('RX', wires=[0], par=[theta])
dev.apply('RX', wires=[1], par=[phi])
dev.apply('CNOT', wires=[0, 1], par=[])
O = qml.expval.PauliY
name = 'PauliY'
dev._expval_queue = [
O(wires=[0], do_queue=False),
O(wires=[1], do_queue=False)
]
dev.pre_expval()
# below are the analytic expectation values for this circuit
res = np.array([dev.expval(name, [0], []), dev.expval(name, [1], [])])
self.assertAllAlmostEqual(res,
np.array([0, -np.cos(theta) * np.sin(phi)]),
delta=3 / np.sqrt(shots))
def test_parametrized_transform_qnode(self, mocker):
"""Test that a parametrized transform can be applied
to a QNode"""
a = 0.1
b = 0.4
x = 0.543
dev = qml.device("default.qubit", wires=2)
@qml.qnode(dev)
def circuit(x):
qml.Hadamard(wires=0)
qml.RX(x, wires=0)
return qml.expval(qml.PauliX(0))
transform_fn = self.my_transform(circuit, a, b)
spy = mocker.spy(self.my_transform, "construct")
res = transform_fn(x)
spy.assert_called()
tapes, fn = spy.spy_return
assert len(tapes[0].operations) == 2
assert tapes[0].operations[0].name == "Hadamard"
assert tapes[0].operations[1].name == "RY"
assert tapes[0].operations[1].parameters == [a * np.abs(x)]
assert len(tapes[1].operations) == 2
assert tapes[1].operations[0].name == "Hadamard"
assert tapes[1].operations[1].name == "RZ"
assert tapes[1].operations[1].parameters == [b * np.sin(x)]
expected = fn(dev.batch_execute(tapes))
assert res == expected
def test_parametrized_transform_tape_decorator(self):
"""Test that a parametrized transform can be applied
to a tape"""
a = 0.1
b = 0.4
x = 0.543
with qml.tape.QuantumTape() as tape:
qml.Hadamard(wires=0)
qml.RX(x, wires=0)
qml.expval(qml.PauliX(0))
tapes, fn = self.my_transform(a, b)(tape)
assert len(tapes[0].operations) == 2
assert tapes[0].operations[0].name == "Hadamard"
assert tapes[0].operations[1].name == "RY"
assert tapes[0].operations[1].parameters == [a * np.abs(x)]
assert len(tapes[1].operations) == 2
assert tapes[1].operations[0].name == "Hadamard"
assert tapes[1].operations[1].name == "RZ"
assert tapes[1].operations[1].parameters == [b * np.sin(x)]
def test_pauliy_expectation(self, shots):
"""Test that PauliY expectation value is correct"""
theta = 0.432
phi = 0.123
dev = plf.QVMDevice(device="2q-pyqvm", shots=shots)
O1 = qml.expval(qml.PauliY(wires=[0]))
O2 = qml.expval(qml.PauliY(wires=[1]))
circuit_graph = CircuitGraph(
[qml.RX(theta, wires=[0]), qml.RX(phi, wires=[1]), qml.CNOT(wires=[0, 1])] + [O1, O2],
{},
)
dev.apply(circuit_graph.operations, rotations=circuit_graph.diagonalizing_gates)
dev._samples = dev.generate_samples()
res = np.array([dev.expval(O1), dev.expval(O2)])
# below are the analytic expectation values for this circuit
self.assertAllAlmostEqual(
res, np.array([0, -np.cos(theta) * np.sin(phi)]), delta=3 / np.sqrt(shots)
)
